Abstract
A surgical instrument handpiece for a surgical instrument, a corresponding surgical instrument, a corresponding medical product set having the surgical instrument handpiece in combination with at least one accessory, a corresponding rinsing device, and a corresponding cleaning method for the internal flushing of the surgical instrument handpiece. The surgical instrument handpiece includes a handle section for proximal handling by an operator and a shaft section that extends from the handle section in a distal longitudinal direction. A tool is arranged or arrangeable by a user in a distal outlet opening of the shaft section at the distal end opposite the handle section. The shaft section has at least one narrowed distal tip section with a reduced cross-sectional area in the region of the distal outlet opening.
Claims
1.-16. (canceled)
17. A surgical instrument handpiece for a surgical instrument, the surgical instrument handpiece comprising: a handle section for proximal handling by an operator; and a shaft section which extends from the handle section in a distal longitudinal direction, wherein a tool is arranged or arrangeable by a user in a distal outlet opening of the shaft section at a distal end opposite the handle section, wherein the shaft section has at least one narrowed distal tip section with a reduced cross-sectional area in a region of the distal outlet opening; and wherein the shaft section comprises an inner roller bearing arrangement for a rotatable mounting of the tool, wherein the inner roller bearing arrangement comprises at least one distal roller bearing and at least one proximal roller bearing, and wherein the at least one distal roller bearing and the at least one proximal roller bearing are arranged in a spaced apart manner by a bearing cage continuously formed between them.
18. The surgical instrument handpiece according to claim 17, wherein a first diameter of the at least one narrowed distal tip section is at least one of: smaller in comparison with a second diameter of a non-narrowed region of the shaft section by a diameter relation factor of a maximum of 95 percent; and between 3.5 and 5.3 millimeters.
19. The surgical instrument handpiece according to claim 17, wherein a first length of the at least one narrowed distal tip section is at least one of: at least 5 percent of a length proportion in relation to an entire second length of the shaft section; and between 5 and 40 millimeters.
20. The surgical instrument handpiece according to claim 17, wherein a transition region designed as a shoulder from the at least one narrowed distal tip section to the non-narrowed region of the shaft section is one or more of being formed in a rounded shape, in a gradually tapering off shape, and in a chamfered shape.
21. The surgical instrument handpiece according to claim 17, wherein the surgical instrument handpiece is adapted to be inserted into a rinsing device in such a manner that, during an internal flushing of the instrument handpiece with a cleaning fluid in a flow direction from proximal to distal, a rinsing pressure present at the distal outlet opening is at least one of: larger than 10 mbar; and is maintained at at least 20 percent of a proximally applied input pressure of the cleaning fluid.
22. The surgical instrument handpiece according to claim 17, wherein the surgical instrument handpiece is adapted to be inserted into a rinsing device in such a manner that, during an internal flushing of the instrument handpiece with a cleaning fluid in a flow direction from proximal to distal, a rinsing pressure present at the distal outlet opening is larger than 600 mbar.
23. The surgical instrument handpiece according to claim 17, wherein the bearing cage is completely closed or is permeable to a fluid in a small area-related hole volume fraction of less than 40 percent.
24. The surgical instrument handpiece according to claim 17, wherein one or both of the at least one distal roller bearing and the at least one proximal roller bearing comprise one or both of non-spherical rolling elements and ceramic rolling elements.
25. The surgical instrument handpiece according to claim 17, further comprising a ring gap having a bearing cage ring gap cross-sectional area, the ring gap being arranged in the at least one narrowed distal tip section, the ring gap being formed at an outer lateral surface of the bearing cage between an inner surface section diameter of an inner surface section as a ring gap outer diameter and a bearing cage outer diameter as a ring gap inner diameter, the bearing cage ring gap cross-sectional area being at least one of: less than or equal to 3.5 mm.sup.2, and less than or equal to a proximal shaft section ring gap cross-sectional area of the shaft section.
26. A surgical instrument handpiece for a surgical instrument, the surgical instrument handpiece comprising: a handle section for proximal handling by an operator; and a shaft section which extends from the handle section in a distal longitudinal direction, wherein a tool is arranged or arrangeable by a user in a distal outlet opening of the shaft section at a distal end opposite the handle section, wherein the shaft section has at least one narrowed distal tip section with a reduced cross-sectional area in a region of the distal outlet opening; and wherein the surgical instrument handpiece is adapted to be inserted into a rinsing device in such a manner that, during an internal flushing of the instrument handpiece with a cleaning fluid in a flow direction from proximal to distal, a rinsing pressure present at the distal outlet opening is at least one of: larger than 10 mbar; and is maintained at at least 20 percent of a proximally applied input pressure of the cleaning fluid.
27. The surgical instrument handpiece according to claim 26, wherein a first diameter of the at least one narrowed distal tip section is at least one of: smaller in comparison with a second diameter of a non-narrowed region of the shaft section by a diameter relation factor of a maximum of 95 percent; and between 3.5 and 5.3 millimeters.
28. The surgical instrument handpiece according to claim 26, wherein a first length of the at least one narrowed distal tip section is at least one of: at least 5 percent of a length proportion in relation to an entire second length of the shaft section of; and between 5 and 40 millimeters.
29. The surgical instrument handpiece according to claim 26, wherein a transition region designed as a shoulder from the at least one narrowed distal tip section to the non-narrowed region of the shaft section is at least one of: formed in a rounded shape; formed in a gradually tapering off shape; and formed in a chamfered shape.
30. The surgical instrument handpiece according to claim 26, wherein the shaft section comprises an inner roller bearing arrangement for a rotatable mounting of the tool, wherein the roller bearing arrangement comprises at least one distal roller bearing and at least one proximal roller bearing, and wherein the at least one distal roller bearing and the at least one proximal roller bearing are arranged in a spaced apart manner by a bearing cage continuously formed between them.
31. The surgical instrument handpiece according to claim 30, wherein the surgical instrument handpiece is adapted to be inserted into a rinsing device in such a manner that, during an internal flushing of the instrument handpiece with a cleaning fluid in a flow direction from proximal to distal, the rinsing pressure present at the distal outlet opening is larger than 600 mbar.
32. The surgical instrument handpiece according to claim 30, wherein the bearing cage is completely closed or is permeable to a fluid in a small area-related hole volume fraction of less than 40 percent.
33. The surgical instrument handpiece according to claim 30, wherein one or both of the at least one distal roller bearing and the at least one proximal roller bearing comprise one or both of non-spherical rolling elements and ceramic rolling elements.
34. The surgical instrument handpiece according to claim 30, further comprising a ring gap having a bearing cage ring gap cross-sectional area, the ring gap being arranged in the at least one narrowed distal tip section, the ring gap being formed at an outer lateral surface of the bearing cage between an inner surface section diameter of an inner surface section as a ring gap outer diameter and a bearing cage outer diameter as a ring gap inner diameter, the bearing cage ring gap cross-sectional area being at least one of: less than or equal to 3.5 mm.sup.2, and less than or equal to a proximal shaft section ring gap cross-sectional area of the shaft section.
35. A rinsing device configured for an internal flushing of an instrument handpiece according to claim 17.
Description
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0142] FIG. 1 is a slightly perspective lateral view of an instrument handpiece (without tool) in an embodiment according to the prior art;
[0143] FIG. 2 is a lateral view of the instrument handpiece (without tool) in the embodiment according to the prior art;
[0144] FIG. 3a is a distal detailed part of a lateral sectional view of the instrument handpiece (without tool) in the embodiment according to the prior art, in particular illustrating the inner roller bearing arrangement for a tool;
[0145] FIG. 3b is, corresponding to the distal detailed part of FIG. 3a, a schematic representation of hydrodynamic flow lines, in particular illustrating the inner through-flow with a cleaning fluid;
[0146] FIG. 4 is a slightly perspective lateral view of the instrument handpiece (without tool) according to the disclosure in a preferred embodiment;
[0147] FIG. 5 is a lateral view of the instrument handpiece (without tool) according to the disclosure in the preferred embodiment;
[0148] FIG. 6a is a distal detailed part of a lateral sectional view of the instrument handpiece (without tool) according to the disclosure in the preferred embodiment, in particular illustrating the inner roller bearing arrangement for a tool;
[0149] FIG. 6b is, corresponding to the distal detailed part of FIG. 6a, a schematic representation of hydrodynamic flow lines, in particular illustrating the inner through-flow through the instrument handpiece (without tool) according to the disclosure with a cleaning fluid corresponding to the preferred embodiment;
[0150] FIG. 7 is a slightly perspective lateral view of a preferred bearing cage in the form of an excerpt representation as a separate component for the inside of the instrument handpiece according to the disclosure corresponding to the preferred embodiment;
[0151] FIG. 8a is a first sectional view of the instrument handpiece (without tool), showing a region of a tool receptacle in a shaft section, wherein said region is proximal to a proximal roller bearing, in the embodiment according to the prior art;
[0152] FIG. 8b is a second sectional view of the instrument handpiece (without tool), wherein said second sectional view is distal to the first sectional view of FIG. 8a and shows the proximal roller bearing in the shaft section, in the embodiment according to the prior art;
[0153] FIG. 9 is a sectional view of the instrument handpiece according to the disclosure, showing a region in the transition to a handle section, wherein said region is proximal to the shaft section;
[0154] FIG. 10a is a first sectional view of the instrument handpiece (without tool) according to the disclosure, showing the region of the tool receptacle in the shaft section, wherein said region is proximal to the proximal roller bearing, according to the preferred embodiment; and
[0155] FIG. 10b is a second sectional view of the instrument handpiece (without tool) according to the disclosure, wherein said second sectional view is distal to the first sectional view of FIG. 10a and shows a central region of the bearing cage according to FIG. 7 in the narrowed distal tip section, according to the preferred embodiment.
DETAILED DESCRIPTION
[0156] In the following, an embodiment of the present disclosure will be described on the basis of the corresponding FIGS. 4 to 6b, FIG. 7, as well as FIGS. 9 and 10, and in this respect it will be contrasted with an embodiment according to the prior art corresponding to FIGS. 1 to 3b as well as FIGS. 8a and 8b. Therefrom further details, features and advantages of the disclosure become apparent.
[0157] Insofar as the instrument handpiece according to the disclosure corresponding to the preferred embodiment according to FIGS. 4 to 6b as well as FIGS. 10a and 10b is identical to the embodiment according to the prior art corresponding to the analogous FIGS. 1 to 3b as well as according to the analogous FIGS. 8a and 8b, or insofar as a distinguishing characteristic according to the disclosure is not discussed, reference will be made to the introductory description and to the designations with regard to the prior art in order to avoid repetitions.
[0158] FIG. 1 and FIG. 2 show a slightly perspective lateral view and a lateral view of an instrument handpiece (without tool) in an embodiment according to the prior art. A surgical instrument handpiece 1 for a surgical instrument comprises an integrally formed handle section 7 which can be handled by an operator (not shown) proximally/in a manner facing away from the patient, as well as a shaft section 8 which extends from the handle section in a distal longitudinal direction/in a longitudinal direction facing the patient. Thereby, a tool (not shown), as for instance a diamond milling cutter or a spiral drill, is arrangeable by a user at the distal end opposite the handle section 7 in a cylinder bore 40 as a distal outlet opening of the shaft section 8. Thereby, the tool (not shown) typically comprises a tool head, like a drill head, a cutter head, a grinding head or a burnishing head, and a tool shaft for the insertion into the cylinder bore 40.
[0159] Furthermore, at the end proximally (facing away from the patient) the instrument handpiece 1 comprises a connection 5 by means of which it can be connected to a torque transmission train, a drive unit, an energy supply unit or the like, as known from the prior art.
[0160] Between the cylinder bore 40 at the distal end adapted for the reception of the tool and the connection 5 there is formed a handle section 7 with a surface profiling 12 (knobs, grooves, etc.) which is adjoined by a cylindrical shaft section 8 in the direction towards distal. The surface profiling 12 consists of radial and axial recesses between which protrusions are formed. Usually, the instrument handpiece 1 will be grasped by the operator at the handle section 7 and will be handled at the handle section 7 during the use thereof.
[0161] The cylindrical shaft section 8 is formed with a constant second diameter D2 (see FIG. 2).
[0162] Furthermore, FIG. 3a and FIG. 3b each show the same distal detailed part of a lateral sectional view of the instrument handpiece (without tool) according to the prior art: on the one hand (FIG. 3a) without any through-flow in the sense of a normal workshop drawing, on the other hand in the fashion of a hydrodynamic schematic representation in a state with a fluid flowing therethrough (FIG. 3b). For reasons of clarity, in FIG. 3b only the flow lines S are provided with a reference numeral, which is why in the sense of the following description reference is made to the designation of the components with reference numerals in the corresponding FIG. 3a.
[0163] Said representations of FIG. 3a and FIG. 3b show in particular the inner entire roller bearing arrangement. Said inner roller bearing arrangement is provided for rotatably arranging a rotatably drivable tool (not illustrated) in the inside of the instrument handpiece 1, in particular of the shaft section 8. In this respect, the views of FIG. 3a and FIG. 3b are discontinued, as is to be suggested by the dot-dashed line (at the right edge of the illustration). The entire roller bearing arrangement comprises a distal ball bearing pair 20, formed of two distal roller bearings (on the left side of the illustration), and a proximal roller bearing pair 22 formed of two proximal roller bearings 22 (on the right side of the illustration). Thereby, all four individual ball bearings, namely the respective ones of the distal ball bearing pair 20 and of the proximal ball bearing pair 22, are all of the same construction. To this end, each individual ball bearing comprises a plurality of balls 30 as spherical rolling elements which roll between a respective inner ring 26 and a respective outer ring 24 or which roll off thereon, whereby said rings are spaced apart from each other. The respective outer ring 24 is fitted in a distal cylindrical inner surface section 33 of the shaft section 8.
[0164] Furthermore, in said sectional view of FIG. 3a and FIG. 3b there are visible an inner tool receptacle 19 for holding or anchoring the tool shaft (not shown) as well as a guide bushing 32 at the proximal end of the shaft section 8. The tool (not shown) which is inserted through the cylinder bore 40 at the distal tool end is preferably exchangeably held or coupled in the tool receptacle 19 and the guide bushing 32 of the instrument handpiece 1 and can be rotatably driven via the proximal connection 5 (see FIGS. 1 and 2).
[0165] The hydrodynamic schematic representation of FIG. 3b illustrates a state of the instrument handpiece 1 where a flow is flowing therethrough, by means of linearly drawn flow lines S. Such a state with a flow flowing therethrough occurs when the instrument handpiece 1 is inserted into a (not shown) rinsing device, like a cleaning and disinfection unit. The longitudinal flow lines S represent an internal flushing of the instrument handpiece 1 with a cleaning fluid, preferably with a hydrophilic or lipophilic cleaning solution, in the flow direction from proximal to distal. In this respect the flow lines S exit from the distal outlet opening 40 (on the left side of the illustration).
[0166] As regards the through-flow through the entire roller bearing arrangement in the direction from the proximal ball bearing pair 22 (on the right side of the illustration) up to the distal ball bearing pair 20 (on the left side of the illustration), said through-flow becomes clearly recognizable by means of the course of the flow lines S of FIG. 3b: First of all, a forced through-flow which is caused by the constructional design in the proximal direction—and, consequently, a hydrodynamically effective cleaning—of the proximal ball bearing pair 22 takes place by flowing around the corresponding balls 30. When exiting the proximal ball bearing pair 22, downstream/towards distal the flow will, however, look for a flow path substantially towards the center axis of the shaft section (in accordance with the path of least flow resistance). Finally, the most part of the cleaning fluid flows through the comparatively large cylindrical opening or bore of the paired inner rings 26, 26 of the distal ball bearing pair 20 and then exists via the distal outlet opening 40 out of the inside of the shaft section 8. In this respect there is hardly any flow through the distal ball bearing pair 20 (on the left side of the illustration) according to the prior art and, thus, the distal ball bearing pair 20 will also not be adequately cleaned (by the fluid).
[0167] The above described course of the through-flow or the flow conditions from proximal to distal through the instrument handpiece 1 in the embodiment according to the prior art will be further illustrated in detail by means of FIGS. 8a and 8b. FIG. 8a, for instance, shows a first sectional view of the conventional instrument handpiece 1 (without tool) which refers to a cross-section through the cylindrical shaft section 8 with a constant second diameter D2 (see also FIG. 2). Here, the first sectional view of FIG. 8a lies within a region of the tool receptacle 19 (see also FIG. 3a) which is arranged more proximal than the proximal roller bearing 22 (FIG. 22). Furthermore, FIG. 8b shows a second sectional view of the conventional instrument handpiece (without tool) which is sectioned distally or in the flow direction further downstream when compared to the first sectional view of FIG. 8a. Thereby, the second sectional view of FIG. 8b sections the proximal roller bearing 22 in the shaft section 8 with the second diameter 8.
[0168] Thereby, in the first and second sectional view (for the prior art: in FIGS. 8a and 8b) reference is particularly made to the hydrodynamic schematical view (for the prior art: in FIG. 3b) which illustrates the state of the instrument handpiece 1 when a fluid is flowing therethrough by means of the linearly drawn flow lines S (or an exemplary selection of the two flow lines from actually a plurality).
[0169] Thereby, the flow lines S step out of a sheet plane which is related to the representation of the sectional view(s) (for the prior art: in FIGS. 8a and 8b); that is to say (ideally) punctiformly in the direction of the viewer. Like, so to speak, an arrow head of an accordingly corresponding flow vector of a flow rate which passes through the sheet plane, a respective flow line S (represented by example/in a selection) is represented.
[0170] Thus, the respective flow line S which is punctiform in the sectional view indicates a cross-sectional area through which a flow is flowing or which is open, respectively, or a (corresponding) flow cross-sectional area. In other words, a point indicated by means of the flow line S in one of the sectional views respectively implies a (flow) cross-sectional area (which is recognizable between contour lines or body edges, or which is an individual one) which is available respectively to a flow path of the through-flow. Consequently, for or during the flushing with the cleaning fluid by means of the (not illustrated) rinsing device, preferably by means of the cleaning and disinfection unit, the (respective flow) cross-sectional area is in a fluid communication with an input connection of the instrument handpiece 1.
[0171] From the first sectional view of FIG. 8a it can be inferred that a cylindrical ring gap cross-sectional area A-R is formed between an outer cylindrical ring gap outer diameter d-R1 and an inner ring gap inner diameter d-R2 for the through-flow (with a punctiformly exiting flow line S). Hence, the ring gap cross-sectional area A-R is calculated as a (respective flow) cross-sectional area on the basis of the subtraction of the two circular areas with the ring gap outer diameter d-R1 or, respectively, with the ring gap inner diameter d-R2. The ring gap cross-sectional area A-R as is shown in FIG. 8a may for instance amount to 2.4 mm.sup.2.
[0172] The second sectional view of FIG. 8b shows the flow situation downstream/distally. Here, in the proximal roller bearing 22 the through-flow flows through two flow spaces or respective (flow) cross-sectional areas which are separated by the inner ring 26. Thereby, these taken together result in an entire roller bearing flow cross-section (for instance 8.5 mm.sup.2), as will be explained in the following: The proximal roller bearing 22 is represented with seven balls 30 as the rolling elements which roll in a rolling off manner between the inner ring 26 with the inner ring diameter d-26 and the outer ring 24 fitted in the shaft section 8 and having the outer ring diameter d-26. A part of the through-flow flows (with a punctiformly exiting flow line S) centrally through a cylindrical bore inner space of the inner ring 26 with a bore cross-sectional area A-B (for instance 4.5 mm.sup.2) according to a bore diameter d-B (for instance 2.4 mm).
[0173] In addition, the other part of the through-flow flows through a roller bearing inner space of the proximal roller bearing 22 with a (free) roller bearing cross-sectional area A-22 (for instance 4.0 mm.sup.2), wherein said roller bearing inner space is formed between the inner ring 26 and the outer ring 24 and is free from the (seven) balls 30, with two punctiformly exiting flow lines S.
[0174] According to the hydrodynamic law of the path according to the least flow resistance and/or according to the flow condition known as wall adhesion condition, in particular in the case of a pipe flow, and/or according to the through-flow through a bed (“Pre-Darcy”), there results hydrodynamically a distribution of the flow rate (in the longitudinal direction of the instrument handpiece 1) with a maximum within the bore cross-sectional area A-B. In contrast thereto, only a small portion of the other part of the through-flow or a portion relatively small thereof when compared to the one part will pass through the roller bearing cross-sectional area A-22.
[0175] In other words, the structure of the conventional instrument handpiece 1 causes in a disadvantageous manner that, when there is a through-flow with a cleaning fluid flowing therethrough, especially the roller bearing (or the here representatively hydrodynamically discussed proximal roller bearing 22) will only experience a low or weak or slow through-flow. In the prior art that circumstance is considered to be particularly disadvantageous in that the flow cross-section is not only not tapered from proximal (the ring gap cross-sectional area A-R, for instance 2.4 mm.sup.2), but even considerably enlarges towards distal (entire roller bearing flow cross-section for instance 8.5 mm.sup.2). As a consequence, the risk exists that a mechanical cleaning effect by means of the cleaning fluid will not ensue in an adequate manner. In particular, the mechanical cleaning effect is determined according to the kinetic energy of the cleaning fluid as a hydrodynamic parameter into which, in turn, the flow rate squared is incorporated.
[0176] The above explained disadvantage of the reduced through-flow in the roller bearing as a result thereof and the, thus, reduced cleaning effect is all the greater in terms of the technical aim of hygienics, in particular in terms of a completely reliable sterilization, inasmuch as exactly the large surfaces of the roller bearings offer particularly much surface area for the adhesion of contaminations like germs, biofilms and the like.
[0177] Thus, on the basis of the first and second sectional view for the conventional instrument handpiece in the FIGS. 8a and 8b the disadvantage of the prior art as described already above with the aid of FIG. 3b becomes especially evident, namely as regards the inadequate (fluid) cleaning effect of the through-flow visualized by means of the flow lines S.
[0178] According to the present disclosure, these disadvantages are remedied. FIGS. 4 to 7 show different views according to an embodiment of an instrument handpiece 1 according to the disclosure. For instance, FIG. 4 and FIG. 5 show [in analogy to FIG. 1 and FIG. 2 for the prior art] a slightly perspective lateral view and a lateral view of the instrument handpiece (without tool) according to the disclosure in a preferred embodiment.
[0179] Unlike in the prior art, the shaft section 8 comprises a narrowed distal tip section 10 in the region of the distal outlet opening 40 (on the left side in FIGS. 4 to 6b). The distal tip section 10 is narrowed/reduced from a second diameter D2 of the shaft section 8 down to a smaller first diameter D1 (see FIG. 5). In other words, the preferred embodiment as shown in FIGS. 4 to 7 of an instrument handpiece according to the disclosure differs from the conventional instrument handpiece according to the prior art as shown in FIGS. 1 to 3b in that the longitudinal shaft section 8 with a second diameter D2 in its distal region of the cylinder bore 40 as a distal outlet opening has a narrowed distal tip section 10.
[0180] As is indicated in FIG. 4 by means of curly brackets, the first length L1 of the distal tip section 10 occupies a distal partial section of the (entire) second length L2 of the (entire) shaft section 8. Between the distal tip section 10 with the first diameter D1 and the shaft section 8 with the second diameter D2 there is circumferentially formed a shoulder or a beveled step as a transition region 11 (see FIG. 5) in a gradually tapering off or chamfered manner.
[0181] Furthermore, FIG. 6a and FIG. 6b show [by analogy to FIG. 3a and FIG. 3b for the prior art] respectively the same distal detailed part of a lateral sectional view of the instrument handpiece (without tool) according to the disclosure in the preferred embodiment: on the one hand (FIG. 6a) without any through-flow in the sense of a workshop drawing; on the other hand in a state with a fluid flowing therethrough (FIG. 6b). For reasons of clarity, in FIG. 6b only the flow lines S as well as the outlet cross-sectional area A for the flow are provided with a reference numeral, which is why in the sense of the following description reference is made to the designation of the components with reference numerals in the corresponding FIG. 6a.
[0182] Said representations of FIG. 6a and FIG. 6b show in particular the inner entire roller bearing arrangement. Said inner roller bearing arrangement is provided for rotatably arranging a rotatably drivable tool (not illustrated) in the inside of the instrument handpiece 1, in particular in the distal tip section 10 of the shaft section 8. The views of FIG. 6a and FIG. 6b (as already the views of FIG. 3a and FIG. 3b) are discontinued, as is suggested by the dot-dashed line (at the right edge of the illustration). The entire roller bearing arrangement comprises a distal needle bearing (or cylindrical roller bearing) 20 (on the left side in the illustration) and a proximal needle bearing (or cylindrical roller bearing) 22 of the same construction (on the right side of the illustration). To this end, the distal needle bearing 20 and the proximal needle bearing 22 each comprise a plurality of preferably ceramic needles 30 as elongated or longitudinal unspherical rolling elements, distributed in uniform angular segments on a respective periphery of a circle. The respective needles 30 are set or arranged in a plurality of corresponding longitudinal grooves 35 in the bearing cage 50 in a manner rotatably movable around their longitudinal central axis. The distal needle bearing 20 and the proximal needle bearing 22 are arranged in a manner spaced apart from each other in the longitudinal direction of the shaft section 8 by means of a cylindrical bearing cage 50 being inserted in the cylindrical inner bore of the distal shaft section 10. In this respect, the respective needles 30 of the distal needle bearing 20 and of the proximal needle bearing 22 roll on a or roll off internally on a cylindrical inner surface section 33 of the distal tip section 10 or of the shaft section 8. Comparable to the prior art, at the proximal end of the shaft section 8 an inner tool receptacle 19 for holding or anchoring the tool shaft (not shown) as well as a guide bushing 32 are recognizable.
[0183] FIG. 6b shows, as already FIG. 3b for the prior art, a schematic representation of hydrodynamic flow lines S. Thus, as far as no differences to the prior art are affected, in order to avoid repetitions reference is made to the explanations regarding FIG. 3b. In contrast to FIG. 3b, FIG. 6b illustrates a state with a fluid through-flow according to the disclosure during an inner through-flow with a cleaning fluid through the instrument handpiece (without tool) according to the disclosure corresponding to the preferred embodiment. Such a state with a fluid through-flow according to the disclosure may in a preferable manner be effected or implemented by the fact that the instrument handpiece 1 according to the disclosure is inserted into a (not shown) rinsing device according to the disclosure, as for instance into a cleaning and disinfection unit. The longitudinal flow lines S represent an internal flushing of the instrument handpiece 1 with a cleaning fluid, preferably with a hydrophilic or lipophilic cleaning solution, in the flow direction from proximal to distal (from the right side to the left side in the illustration). In this respect, the flow lines S exit from the distal outlet opening 40 (on the left side of the illustration) of the narrowed distal tip section 10 with a correspondingly reduced outlet cross-sectional area A of the flow.
[0184] By means of the course of the flow lines S of FIG. 6b the through-flow according to the disclosure also through the distal needle bearing 20 as a distal roller bearing is clearly recognizable. Almost along the entire length of the shaft section 8, in particular on the first length L1 of the distal tip section, the flow lines run along the inner surface section 33 of the distal tip section 10 or of the shaft section 8. In particular, only after passing also through the distal needle bearing 20 or only shortly before the flow exit from the distal outlet opening 40 with a reduced outlet cross-sectional area A the flow takes a flow path downstream substantially towards the center axis of the shaft section. Thus, according to the disclosure a hydrodynamically effective (fluid) cleaning also of the distal needle bearing 20 as a distal roller bearing takes place.
[0185] This is because, due to the narrowed distal tip section 10 according to the disclosure, for the improvement of the cleaning effect the flow velocity according to the reduced outlet cross-sectional area A and the pressure in the distal tip section 10 of the instrument handpiece 1 are increased. This is caused by the change in diameter of the distal tip section 10 from the outer diameter of 5.6 mm as an exemplary second diameter D2 to the outer diameter of 4.4 mm as an exemplary first diameter D1 in the region of the first 20 mm as an exemplary first length L1.
[0186] Moreover, the special constructional design of the bearing cage 50 as a continuous pipe provides for a lesser soiling during use and at the same time for an optimized cleaning by the targeted guidance of the cleaning fluid. A small portion of the cleaning fluid still gets through the tool opening 40 as a distal outlet opening of the instrument handpiece 1 and here also provides for an optimal cleaning, as no obstructing parts block the flow of the cleaning fluid. FIGS. 6a and 6b illustrate the constructive details with regard to the installation or the mounting of the bearing cage 50 which can be seen in greater detail as an individual component in FIG. 7.
[0187] The technical effect on the course of the flow lines S due to the constructional design as well as due to the arrangement of the particularly preferred embodiment with a bearing cage 50 is in particular again comprehensible by means of FIG. 6b. It can be recognized that the bearing cage 50 even causes a forced through-flow through the distal needle bearing 20, that is to say said needle bearing 20 will be passed in any case and, thus, cleaned (by the fluid). In particular by the installation of such a bearing cage 50, in addition a large degree of independence from a proximally applied input pressure of the cleaning fluid is achieved in a preferable manner, which further promotes the stability of a cleaning method according to the disclosure.
[0188] FIG. 7 shows in the form of an enlarged excerpt representation by reference to FIG. 6a and FIG. 6b, a slightly perspective lateral view of a bearing cage 50, in a manner as it may preferably be provided as a separate component of a roller bearing arrangement for the tool in the inside of the instrument handpiece 1 according to the disclosure. From said representation of FIG. 7 it can be clearly inferred that the bearing cage 50 in the form of a cylindrical pipe arranges a distal roller bearing 20 (on the left side of the illustration) and a proximal roller bearing 22 (on the right side of the illustration) in a spaced apart manner. Thereby, the distal roller bearing 20 and the proximal roller bearing 22 are implemented by means of respectively five needles 30 as unspherical rolling elements uniformly distributed at the circumference of the bearing cage 50. The needles 30 in turn are arranged in corresponding longitudinal grooves 35 of the bearing cage 50 in a manner being rotatable/rolling-off around their longitudinal axis. Furthermore, at the proximal end of the bearing cage 50 there can be recognized a plurality of spherical guide elements 60 as well as a slipping-off surface 61.
[0189] FIG. 9 shows a sectional view of the instrument handpiece 1 according to the disclosure, which depicts a region in the transition 12 to the handle section 7 (according to FIG. 4), wherein said region is proximal to the shaft section 8. It can be derived that a (cylindrical) ring gap cross-sectional area A-R (for instance approximately 3.6 mm.sup.2) which belongs to the cross-section of FIG. 9 is formed between a corresponding outer cylindrical ring gap outer diameter d-R1 (for instance approximately 3.2 mm) and a corresponding inner ring gap inner diameter d-R2 (for instance approximately 2.4 mm) for the through-flow (with a punctiformly exiting flow line S).
[0190] Furthermore, FIG. 10a and FIG. 10b show [by analogy to FIG. 8a and FIG. 8b for the prior art] a first and a second lateral view of the instrument handpiece 1 (without tool) according to the disclosure in the preferred embodiment according to FIGS. 4 to 7: First of all FIG. 10a shows a first sectional view in a region of the tool receptacle 19 in the shaft section 8 with the second diameter D2, wherein said region is proximal to the proximal roller bearing 22 (according to FIG. 6a).
[0191] And furthermore FIG. 10b shows a second sectional view of a central region of the bearing cage 50 (according to FIGS. 6a and 7) in the narrowed distal tip section 10 according to the disclosure with the first diameter D1, wherein said second sectional view is distal to the first sectional view of FIG. 10a.
[0192] By analogy to the above discussion for the prior art (on the basis of FIGS. 8a and 8b referring thereto), in the first and second sectional view of FIGS. 10a and 10b reference is made in particular to the hydrodynamic schematic representation in FIG. 6b which illustrates the state of the instrument handpiece 1 when a flow is flowing therethrough by means of the linearly drawn flow lines S (or an exemplary selection of the two flow lines actually from a plurality).
[0193] From FIG. 10a it can be inferred that a (cylindrical) ring gap cross-sectional area A-R (for instance approximately 3.6 mm.sup.2) belonging to the cross-section of the shaft section 8 in FIG. 10a is formed between a corresponding outer cylindrical ring gap outer diameter d-R1 (for instance approximately 4.5 mm) and a corresponding inner ring gap inner diameter d-R2 (for instance approximately 4.0 mm), for the through-flow (with a punctiformly exiting flow line S).
[0194] Accordingly, it may be particularly preferred that the ring gap cross-sectional area A-R belonging to the cross-section of the shaft section 8 in FIG. 10a approximately corresponds to the (cylindrical) ring gap cross-sectional area A-R belonging to the cross-section of FIG. 9 (area relation to each other of 90% to 110%, further preferred of 98% to 102%, in particular approximately 100%). This results in an advantageous uniformity of the course of the rinsing pressure or of the flow rate or of the kinetic energy in the instrument handpiece 1 from proximal to distal.
[0195] From FIG. 10b which concerns a distal cross-section according to the disclosure there can be inferred under reference to FIG. 6a and FIG. 6b that the narrowed distal tip section 10 with the first diameter D1 comprises the cylindrical (in the longitudinal direction of the instrument handpiece 1) continuous bearing cage 50 in a manner being internally spaced apart. For the through-flow (with a punctiformly exiting flow line S) there is formed a corresponding ring gap around the bearing cage 50. On the other hand, at least the proximal end, preferably also the distal end, of the bearing cage 50 is/are closed so that the central cylinder volume of the bearing cage 50 cannot be/will not be exposed to a through-flow.
[0196] Behind the cross-section of the distal tip section 10 as shown in FIG. 10b through a (in longitudinal direction) central region of the bearing cage 50 in the direction of view there can be recognized the five needles 30 as unspherical rolling elements (see FIG. 7) and being uniformly distributed at the circumference of the bearing cage 50.
[0197] Thereby, the corresponding ring gap within the inner surface section 33 is formed at an outer lateral surface of the continuously formed bearing cage 50 between an inner surface section diameter d-33 (for instance approximately 3.8 mm) as a ring gap outer diameter and a bearing cage outer diameter d-50 (for instance approximately 3.3 mm) as a ring gap inner diameter. Here, the ring gap arranged around the bearing cage 50 has a bearing cage ring gap cross-sectional area A-50 (for instance approximately 2.8 mm.sup.2).
[0198] Preferably, the bearing cage ring gap cross-sectional area A-50 may be less than or equal to 3.5 mm.sup.2, further preferred less than or equal to approximately 3 mm.sup.2 and particularly preferred less than or equal to 2.8 mm.sup.2. Alternatively or cumulatively, the bearing cage ring gap cross-sectional area A-50 may be less than or equal to a flow cross-sectional area through which a free through-flow is possible in a region of the instrument handpiece 1 being proximal thereto, as is for instance shown in FIGS. 10a and/or 9. Further preferred, the bearing cage ring gap cross-sectional area A-50 may be less than or equal to a proximal shaft section ring gap cross-sectional area A-R (see FIG. 9).
[0199] In particular, according to the disclosure the rinsing pressure being applied or present at the distal outlet opening (with the reference numeral 40, see FIGS. 4 to 6a) or in the bearing cage ring gap cross-sectional area A-50 in the flow direction from proximal to distal can be positively increased. As a result thereof, the instrument handpiece according to the disclosure offers a remedy for a situation being technically problematic in the prior art which can occur in form of a possibly too low respective rinsing pressure in particular in a situation with a high hospital occupancy rate. As an example, the entire proximal input pressure of the cleaning fluid, which input pressure is supplied in a cleaning and disinfection unit (not shown) (for instance of the type “MIELE G 7825” construction 80) as a rinsing device from an external source to a number of several connected instrument handpieces to be cleaned, may amount to a maximum of approximately 1600 mbar in the sense of a proximal absolute pressure. In the sense of a pressure difference/an excess pressure/a pressure delta with respect to the atmospheric ambient pressure of for instance approximately 950 mbar, this results in a maximum (proximal) rinsing pressure for an individual connected instrument handpiece 1 of approximately 650 mbar. When there are several instrument handpieces present or connected, then said maximum (proximal) rinsing pressure is, however, subdivided into said several handpieces and is, thus, reduced to a respective rinsing pressure. The exemplary cleaning and disinfection unit provides a maximum of 22 connections (‘Luer-lock: type Miele”, connection inner diameter 3 mm; thus a flow cross-section: A=approximately 7 mm.sup.2). In the case of 11 connected instrument handpieces, i.e. the half, a reduction of the respective (proximal) rinsing pressure to approximately 500 mbar could be noticed proximally. In the case of 22 (of 22) connected instrument handpieces there could be observed that the respective (proximal) rinsing pressure was proximally reduced or decreased even further to approximately 315 mbar. Thus, the respective (proximal) rinsing pressure is available at the entrance of the instrument handpiece (proximal handle section flow cross-section of for instance Ø1.7 mm, A=2.27 mm.sup.2).
[0200] The (proximal) rinsing pressure applied proximally of the exemplary cleaning and disinfection unit is reduced by further taking into account various flow resistances, like the pipe friction along the inner through-flow of the instrument handpiece, from proximal to distal furthermore to a distally present (distal) rinsing pressure.
[0201] The present disclosure guarantees that also in case of a low respective rinsing pressure a reliable and adequate fluid cleaning will take place. The narrowed distal tip section 10 effects that also still in the distal region an effective rinsing pressure is present. In particular the particularly preferred embodiment with the continuously formed bearing cage 50 enables a powerful forced through-flow in the surrounding bearing cage ring gap cross-sectional area A-50. Hence, despite flow pressure losses there takes place an effective fluid cleaning even downstream/distal of the non-narrowed shaft section 8, namely in the distal tip section 10. Said fluid cleaning guarantees a quasi undiminished mechanical cleaning performance in the distal roller bearing 20 and in the proximal roller bearing 22. Insofar even the proximal roller bearing 22 receives the entire rinsing flow of the cleaning fluid.
