Endoscope and method for producing an endoscope, and latching element

Abstract

An endoscope having an elongate shaft and a system tube, which extends inside the shaft and in which an image carrier is arranged, the system tube is held in an axial direction of the shaft by means of at least one resilient latching element, and a method for producing such an endoscope and to a latching element for such an endoscope.

Claims

1. An endoscope comprising: an elongate shaft; and a system tube that extends inside the shaft and in which an image carrier is arranged; wherein the system tube is held in an axial direction of the shaft by at least one resilient latching element.

2. The endoscope according to claim 1, wherein the resilient latching element forms an abutment for a spring element, and the spring element loads the system tube in a distal direction of the elongate shaft against a limit stop.

3. The endoscope according to claim 2, wherein the limit stop is formed in a distal end area of the shaft.

4. The endoscope according to claim 3, wherein the limit stop is formed by a cover glass, secured in the distal end area of the shaft; and the system tube bears against the cover glass via an objective arranged between the cover glass and the image carrier.

5. The endoscope according to claim 1, further comprising: an endoscope head arranged at a proximal end of the shaft, wherein the system tube extends into the endoscope head, and the at least one resilient latching element is received in the endoscope head and connects a proximal end area of the system tube and a housing of the endoscope head.

6. The endoscope according to claim 5, wherein at the least one resilient latching element is latched in at least one latching recess formed on an inner face of an inner sleeve of the endoscope head.

7. The endoscope according to claim 1 wherein the system tube is held releasably.

8. The endoscope according to claim 1, wherein at least one resilient latching element is designed as a latching sleeve with at least one resilient latching hook arranged on the outside.

9. The endoscope according to claim 1, wherein the at least one resilient latching element is designed as a resilient clamping ring.

10. The endoscope according to claim 1, wherein at least on resilient latching element has at least one latching lugs for securing against rotation.

11. The endoscope according to claim 1, wherein at least one resilient latching element has at least one peripheral sealing element and at least one recess for receiving a desiccant.

12. A method for producing an endoscope comprising the following steps of: making available an endoscope housing including an outer tube of an elongate shaft and an endoscope head connected to a proximal end of the shaft, which endoscope head has an inner sleeve having at least one latching recess on an inner face thereof; making available a system precursor including a system tube with an image carrier received therein, and a coupling element fixedly connected to a proximal end of the system tube; pushing a compression spring and a resilient latching element onto the coupling element from a proximal direction; screwing an eyepiece mount onto a proximal end of the coupling element; pushing the system precursor into the endoscope housing in a distal direction as far as a limit stop; and moving the latching element in the distal direction on the coupling element until the latching element latches into the at least one latching recess.

13. The method according to claim 12, wherein the endoscope housing further includes an inner tube which is arranged in the outer tube and which is fixedly connected to the inner sleeve of the endoscope head, wherein upon insertion of the system precursor into the endoscope housing, the system tube is pushed into the inner tube and the limit stop is formed in the distal end area of the inner tube.

14. The method according to claim 12, wherein an eyepiece is inserted into the eyepiece mount and is adjusted after the eyepiece mount has been screwed on and before the system precursor is pushed into the endoscope housing.

15. (canceled)

16. The method according to claim 13, wherein an eyepiece is inserted into the eyepiece mount and is adjusted after the eyepiece mount has been screwed on and before the system precursor is pushed into the endoscope housing.

17. An endoscope comprising: a shaft; a system tube that extends inside the shaft; an image carrier arranged inside the system tube; a latching element that secures the system tube in an axial direction of the shaft; a limit stop formed by a cover glass secured in a distal end area of the shaft; a spring element that abuts the latching element and loads the system tube in a distal direction of the shaft against the limit stop; an endoscope head arranged at a proximal end of the shaft; the system tube extends into the endoscope head and the latching element connects the system tube to the endoscope head.

18. The endoscope of claim 17, wherein the image carrier inside the system tube bears against the cover glass of the limit stop via an objective arranged between the system tube and the cover glass.

19. The endoscope of claim 18, wherein the endoscope head has a housing and an inner sleeve, and a recess is formed on an inner face of the inner sleeve; and the latching element releasably latches to the recess, thereby releasably connecting a proximal end area of the system tube with the housing of the endoscope head.

Description

[0036] Further aspects of the invention will become clear from the following description of two preferred illustrative embodiments and from the attached drawing, in which:

[0037] FIG. 1 shows a first illustrative embodiment of an endoscope according to the invention in a partially sectioned side view;

[0038] FIG. 2 shows a part of the internal structure of the endoscope head of the endoscope according to FIG. 1 in a longitudinal section;

[0039] FIG. 3 shows a part of the internal structure of the endoscope head of the endoscope according to FIG. 1 in a sectioned side view;

[0040] FIG. 4 shows the distal end of the shaft of the endoscope according to FIG. 1 in a partially sectioned side view;

[0041] FIG. 5 shows the latching sleeve of the endoscope according to FIG. 1 in an oblique view;

[0042] FIG. 6 shows a second illustrative embodiment of an endoscope according to the invention in a view corresponding to FIG. 1;

[0043] FIG. 7 shows a part of the internal structure of the endoscope head of the endoscope according to FIG. 6 in a longitudinal section;

[0044] FIG. 8 shows a part of the internal structure of the endoscope head of the endoscope according to FIG. 6 in an oblique view;

[0045] FIG. 9 shows the clamping ring of the endoscope according to FIG. 6 in an oblique view.

[0046] FIG. 1 shows an endoscope according to a first embodiment of the invention in a partially sectioned side view. The endoscope 1 comprises an elongate shaft 2 and an endoscope head 3 arranged at the proximal end of the shaft 2. The distal end area 4 of the endoscope shaft 2 is shown in section in FIG. 1. The endoscope head 3, which is likewise shown partially sectioned in FIG. 1, is connected to an outer tube 6 of the shaft via a cone 5. The endoscope head 3 has a housing 7, at the proximal end of which an eyepiece cup 8 is fitted. The housing 7 of the endoscope head 3 also carries a light attachment piece 9. In the parts of the endoscope shown in section in FIG. 1, further components are indicated which are shown enlarged in FIGS. 2 to 5 and which are described in more detail below.

[0047] FIG. 2 shows a part of the internal structure of the endoscope head 3 of the endoscope 1 in longitudinal section. In the illustrative embodiments of the invention described here, the image carrier is configured as a system of rod lenses arranged one after another, of which the proximal portion of the proximal rod lens 10 can be seen in FIG. 2. The rod lens 10, tapered in its central portion, is received in a system tube 11 which also receives the rod lenses which are arranged further in the distal direction and which are not shown in FIG. 2. The system tube 11 is connected by welding to an approximately sleeve-shaped coupling element 12 attached to the proximal end of the system tube 11. In its proximal end area, the outer sleeve-shaped part of the coupling element 12 has an inner thread 13 into which an approximately sleeve-shaped eyepiece mount 14 with an outer thread 15 is screwed. An eyepiece sleeve 16, which comprises optical elements (not shown in FIG. 2) of the eyepiece, is held adjustably in the eyepiece mount 14. An optics spring 17 configured as a helical compression spring bears on the distal side of the eyepiece mount 14 and is supported distally on an annular collar 18 of a rod lens mount 19. The proximal end of the proximal rod lens 10 of the image carrier is held in the rod lens mount 19. By way of a spacer (not shown in FIG. 2), which bears on a shoulder 20 of the rod lens mount, the rod lens 10 is loaded in the distal direction by the optics spring 17; the distal side of the eyepiece mount 14 here serves as an abutment for the optics spring 17. Since the further rod lenses following the rod lens 10 in the distal direction bear on the rod lens 10 and on each other via spacers, the entire rod lens system is thus pretensioned in the distal direction against a distal limit stop of the rod lens system and is thereby fixed in the axial direction. In the radial direction, i.e. in the transverse direction of the endoscope 1, the rod lens 10 and the further rod lenses and components can be fixed by narrow tolerances.

[0048] As is also shown in FIG. 2, an inner sleeve 21, which is fixedly connected to the housing 7, is arranged in the housing 7 of the endoscope head 3. In its proximal end portion, the inner sleeve 21 has, on the inside, a distally narrowing conical taper 22, in the distal direction from which a circumferential latching groove 23 is arranged, which is configured as an indentation in the inner face of the inner sleeve 21. A latching element, which is configured as a latching sleeve 24 in the illustrative embodiment shown, is pushed onto the outside of the coupling element 12. The latching sleeve is closed annularly in its proximal end area and has, in its distal end area, resiliently held latching hooks 25, which engage in the latching grove 23. As is also shown in FIG. 2, the distal side of the latching sleeve 24 forms an abutment for a compression spring 26 which is configured as a helical spring and which is supported distally on an annular collar 27 of the coupling element 12. Since the latching sleeve 24 is held in the groove 23 against displacement in the proximal direction, the coupling element 12, and thus the system tube 11, is pressed in the distal direction by the compression spring 26 against a limit stop (described further below) for the system tube 11 and is thereby fixed in the axial direction. The forces required for fixing the components and acting on the rod lens system or the system tube 11 can be adjusted through the design of the optics spring 17 and of the compression spring 26.

[0049] FIG. 3 shows the internal structure of the endoscope head 3 in a sectioned side view, in which the housing 7 of the endoscope head 3, composed of several components, is depicted only partially. As is shown in FIG. 3, the inner sleeve 21 is fixedly connected to the housing 7. The inner sleeve 21 is in turn fixedly connected, for example soldered, to an inner tube 28 in which the system tube 11 is guided. In FIG. 3, moreover, two of three adjusting bores 29 can be seen into which adjusting screws can be inserted in order to adjust the eyepiece sleeve 16 relative to the rod lens 10 or relative to the optical axis 30. The rod lens 10 and the eyepiece sleeve 16 are not shown in FIG. 3.

[0050] FIG. 4 shows the distal end area 4 of the shaft 2 of the endoscope 1 according to FIG. 1 in an enlarged view and in section. As can be seen from FIG. 4, the inner tube 28 extends inside the outer tube 6. Illumination light guides (not shown) are arranged in the interspace 31 between the outer tube 6 and the inner tube 28. Serving as a distal closure of the lumen surrounded by the inner tube 28, a cover glass 32 is soldered into the inner tube 28. For the sake of clarity, the interspace 33, filled with solder, is shown wider in FIG. 4. The cover glass 32 is followed in the proximal direction by the objective 34 and the rod lenses of the image carrier (not shown in FIG. 4). The objective 34 comprises a first objective lens 35 and an objective lens unit 36, which comprises further lens elements not shown in detail in FIG. 4. The cover glass 32, the objective lens 35 and said further lens elements can be separated from one another by spacers (not shown in FIG. 4). The objective lens unit 36 is inserted fixedly by adhesive bonding into an objective sleeve 37, which is fixedly connected to the distal end of the system tube 11, the latter not necessarily extending into the end area 4 shown in FIG. 4.

[0051] As has been described in connection with FIG. 2, the rod lens system is loaded by the optics spring 17 against a distal limit stop of the rod lens system. This limit stop, against which the rod lens system is axially fixed inside the system tube 11, is formed by the objective lens unit 36 fixedly connected to the distal end of the system tube 11. The system tube 11 is loaded by the compression spring 26 in the distal direction against a limit stop for the system tube 11, which limit stop is provided by the cover glass 32 fixedly held in the inner tube 28 or by the first objective lens 35 bearing on the cover glass 32, optionally via spacers. This limit stop for the system tube 11 is reached when the objective lens unit 36 bears, optionally via a spacer, on the first objective lens 35. In this way, the system tube 11 and the optical system received therein are fixed in the axial direction inside the endoscope 1.

[0052] FIG. 5 shows the latching sleeve 24 in an enlarged and oblique view, as seen from the distal direction. As can be seen from FIG. 5, the distal end of the latching sleeve 24 is divided by slits 38 into a plurality of resilient latching segments 39. At their distal end, the latching segments 39 carry the outwardly directed latching hooks 25. At the proximal end, the latching sleeve 24 is formed as a closed ring.

[0053] In the production of the endoscope 1 designed as described above, the endoscope housing, which comprises the outer tube 6, the housing 7 of the endoscope head 3, the inner sleeve 21 and the inner tube 28, is pre-assembled and made ready. The pre-assembled endoscope housing likewise comprises the light attachment piece 9 and the illumination light guides routed through the latter as far as the distal end area 4 of the endoscope 1, and, if appropriate, further components. Moreover, in the pre-assembled endoscope housing, the cover glass 32 is soldered into the inner tube 28 at the distal end thereof. Moreover, likewise as a pre-assembled group, the system precursor is made available, which comprises the system tube 11, the rod lenses and spacers received in the latter, the coupling element 12 welded to the system tube 11, and, if appropriate, further components. The system precursor also comprises the objective lens unit 36, which is adhesively bonded into the objective sleeve 37, wherein the objective sleeve 37 is fixedly connected to the distal end of the system tube 11. Moreover, an eyepiece assembly is made available which comprises the eyepiece mount 14, the rod lens mount 19 inserted into the latter and crimped at the proximal end, and the optics spring 17 arranged on the outside of the rod lens mount 19.

[0054] To assemble the endoscope 1, first the compression spring 26 and then the latching sleeve 24 are pushed onto the coupling element 12 from the proximal direction. The eyepiece mount 14 is then screwed with its outer thread 15 into the inner thread 13 of the coupling element, wherein the coupling element 12 is pulled against the disk 43 of the eyepiece mount 14. The proximal rod lens 10 is in this way placed under the pretensioning force exerted by the optics spring 17 via the rod lens mount 19, as a result of which the rod lens system is pressed against the objective lens unit 36 and thus fixed. After the eyepiece sleeve 14 has been screwed into the coupling element 12, the latching sleeve 24 bears on the disk 43 of the eyepiece mount 14 and is also secured by the latter against being lost. The eyepiece sleeve 16, with the eyepiece lenses received in it, is inserted into the eyepiece mount 14 and, by means of adjusting screws guided through the adjusting bores, is adjusted relative to the optical axis 30 of the rod lens system. The assembly made up of the system precursor with the compression spring 26 and the latching sleeve 24 and of the eyepiece group represents the optics unit of the endoscope 1, which comprises almost the entire optical system of the endoscope 1.

[0055] The optics unit is now pushed from the proximal direction into the pre-assembled endoscope housing, wherein the system tube 11 is pushed into the inner tube 28. The latching hooks 25 are pressed inward over the taper 22 of the inner sleeve 21 but do not yet latch in the latching groove 23. After the objective lens unit 26 connected to the inner tube 21 has reached the limit stop formed by the cover glass 32 and the first objective lens 35, the latching sleeve 24 is displaced farther in the proximal direction until the latching hooks 25 latch in the latching groove 23. The compression spring 26 is thus compressed, which thereby generates the force necessary for axially fixing the optics unit. The optics unit is in this way secured against axial displacement. Since the system tube 11 is guided inside the inner tube 28 with narrow tolerances, the optics unit as a whole is sufficiently fastened inside the endoscope 1; an adjustment or an additional locking is not needed. In addition, the optics unit can be fixed against a rotation about the longitudinal axis of the endoscope 1; however, this too can be omitted. Moreover, further work steps, such as the introduction of desiccant, can be carried out. Finally, the endoscope head 3 is tightly closed off by attachment of the eyepiece cup 8 and of the eyepiece cover glass.

[0056] To remove the system precursor, the endoscope head 3 can be opened and the eyepiece mount 14 can be unscrewed from the coupling element 12. The latching segments 39 of the latching sleeve 24 are pressed together via a tool pushed into the taper 22, until the latching hooks 25 disengage from the latching groove 23. The latching sleeve 24 can then be pulled off in the proximal direction, and the system precursor can be pulled out of the endoscope housing.

[0057] FIG. 6 shows, in a view corresponding to FIG. 1, an endoscope 1′ according to a second illustrative embodiment of the invention. As is shown in the longitudinal section through the endoscope head 3 in FIG. 7, the latching sleeve 24 is here replaced by an elastically deformable clamping ring 40 configured as a non-continuous ring, which clamping ring 40 is latched in the latching groove 23 and, in a manner corresponding that described above, serves as a proximal abutment of the compression spring 26 and fixes the optics unit in the endoscope housing. FIG. 7 moreover shows an example of an eyepiece lens 44 inserted into the eyepiece sleeve 16. As can be seen in FIG. 8, in an oblique view from the proximal direction, the latching groove 23 in this embodiment does not go all the way round, and instead the inner sleeve 21′ has two circumferential interruptions through which there emerge a widened part 41 and two eyelets 42 of the clamping ring 40, which are arranged on both sides of the interruption of the clamping ring 40. The clamping ring 40 with the widened part 41 and the eyelets 42 is shown in an oblique view in FIG. 9. In other respects, the endoscope 1′ according to the second illustrative embodiment of the invention is constructed like the above-described endoscope 1.

[0058] To produce the endoscope 1′, the procedure followed is the one described in the first illustrative embodiment of the invention, with the endoscope housing, the system precursor and the eyepiece unit being made available correspondingly. The compression spring 26 and the clamping ring 40 are then pushed onto the coupling element 12. The eyepiece mount 14 is then screwed into the coupling element 12, after which the eyepiece sleeve 16 can be inserted and the eyepiece can be adjusted. The optics unit pre-assembled in this way can now be pushed into the endoscope housing until the objective lens unit 36, as described above, reaches the limit stop defined by the cover glass 32. The clamping ring 40, which is not yet latched in the latching groove 23 but instead bears on the disk 43 of the eyepiece mount 14, is then moved in the distal direction to permit latching. In doing this, the clamping ring 40 is pressed together over the taper 22 and finally latches in the latching groove 32 by means of elastic recovery. In a manner corresponding to that described for the first illustrative embodiment of the latching sleeve 24, the clamping ring 40 forms the distal abutment for the compression spring 26 which subjects the coupling element 12 and therefore the system tube 11 to the force necessary for axial fixing. In the transverse direction, the system tube 11 is held inside the inner tube 28 by narrow tolerances.

[0059] For disassembly, the eyepiece mount 14 can be unscrewed from the coupling element 12. The clamping ring 40 can then be contracted by pressing the eyelets 42 together by means of a tool, made to disengage from the latching groove 32 and pulled off in the proximal direction. The system precursor can thereafter be removed, by the system tube 11 being pulled out of the inner shaft 28.

[0060] For the sake of clarity, not all the reference signs are shown in all of the figures. Reference signs not explained in connection with one figure have the same meaning as in the other figures.

LIST OF REFERENCE SIGNS

[0061] 1, 1′ endoscope [0062] 2 shaft [0063] 3 endoscope head [0064] 4 distal end area [0065] 5 cone [0066] 6 outer tube [0067] 7 housing [0068] 8 eyepiece cup [0069] 9 light attachment piece [0070] 10 rod lens [0071] 11 system tube [0072] 12 coupling element [0073] 13 inner thread [0074] 14 eyepiece mount [0075] 15 outer thread [0076] 16 eyepiece sleeve [0077] 17 optics spring [0078] 18 annular collar [0079] 19 rod lens mount [0080] 20 shoulder [0081] 21, 21′ inner sleeve [0082] 22 taper [0083] 23 latching groove [0084] 24 latching sleeve [0085] 25 latching hook [0086] 26 compression spring [0087] 27 annular collar [0088] 28 inner tube [0089] 29 adjusting bore [0090] 30 optical axis [0091] 31 interspace [0092] 32 cover glass [0093] 33 interspace [0094] 34 objective [0095] 35 objective lens [0096] 36 objective lens unit [0097] 37 objective sleeve [0098] 38 slit [0099] 39 latching segment [0100] 40 clamping ring [0101] 41 widened part [0102] 42 eyelet [0103] 43 disk [0104] 44 eyepiece lens