FORCE SENSING DEVICE, MEDICAL ENDODEVICE AND PROCESS OF USING SUCH ENDODEVICE

Abstract

A force sensing device is disclosed that includes a housing tip, a plurality of sensors stationarily spaced from each other, and a spring element connecting the housing tip to the sensors such that moving the housing tip and the sensor relative to each other causes a resilient deformation of the spring element. The spring element is configured to arrange the housing tip in a zero position relative to the sensors by a spring force of the spring element. The force sensing device is also equipped with a spring tensioning structure configured to adapt the spring force of the spring element.

Claims

1.-34. (canceled)

35. A force sensing device comprising: a housing tip that is essentially dome shaped; a plurality of sensors stationarily spaced from each other; a spring element connecting the housing tip to the plurality of sensors such that moving the housing tip and the plurality of sensors relative to each other causes a resilient deformation of the spring element; and a spring tensioning structure, wherein the spring element is configured to arrange the housing tip in a zero position relative to the plurality of sensors by a spring force of the spring element, and wherein the spring tensioning structure is configured to adapt the spring force of the spring element.

36. The force sensing device of claim 35, wherein the plurality of sensors comprises three sensors.

37. The force sensing device of claim 35, wherein the plurality of sensors are unidirectional sensors.

38. The force sensing device of claim 35, further comprising a plurality of sensor actuators, wherein the plurality of sensors are a plurality of force sensors, each sensor actuator of the plurality of sensor actuators is associated with a respective force sensor of the plurality of force sensors, the plurality of sensor actuators are coupled to the housing tip such that moving the housing tip out of the zero position, relative to the plurality of force sensors, causes at least one sensor actuator of the plurality of sensor actuators to act on its respective force sensor, and the plurality of sensor actuators are stationarily mounted to the housing tip and/or each of the plurality of sensor actuators is adjustable in its extension towards its respective force sensor.

39. The force sensing device of claim 35, further comprising a sensor support plate on which the plurality of sensors are mounted, wherein the sensor support plate preferably is a printed circuit board.

40. The force sensing device of claim 39, wherein the sensor support plate is essentially ring-shaped and the plurality of sensors are regularly distributed about a central hole of the ring-shaped sensor support plate.

41. The force sensing device of claim 35, wherein the spring tensioning structure comprises a screw member and a screw socket such that by screwing the screw member into or out of the screw socket the spring force of the spring element is adapted.

42. The force sensing device of claim 35, wherein the spring element comprises a helical spring being connected to the plurality of sensors at one of its longitudinal ends and connected to the housing tip at the other one of its longitudinal ends.

43. The force sensing device of claim 42, wherein the spring tensioning structure comprises a screw member and a screw socket such that by screwing the screw member into or out of the screw socket the spring force of the spring element is adapted and wherein the screw member extends along the helical spring.

44. The force sensing device of claim 35, further comprising a safety structure limiting a maximum movement of the housing tip and the plurality of sensors relative to each other.

45. The force sensing device of claim 35, further comprising a guiding structure predefining possible movements of the housing tip and the plurality of sensors relative to each other, wherein the guiding structure is configured to prevent rotational movements of the housing tip and the plurality of sensors about a longitudinal axis of the force sensing device relative to each other.

46. The force sensing device of claim 45, wherein the guiding structure is configured to limit lateral shifting of the housing tip and the plurality of sensors relative to each other, and/or to limit the movements of the housing tip and the plurality of sensors relative to each other to five degrees of freedom.

47. The force sensing device of claim 44, further comprising a guiding structure predefining possible movements of the housing tip and the plurality of sensors relative to each other, wherein the guiding structure is configured to prevent rotational movements of the housing tip and the plurality of sensors about a longitudinal axis of the force sensing device relative to each other, and wherein the safety structure and the guiding structure are embodied by at least one projection stationary to one of the housing tip or the plurality of sensors and at least one corresponding recess stationary to the other one of the housing tip and the plurality of sensors, the at last one recess receiving the at least one projection.

48. The force sensing device of claim 35, wherein the force sensing device includes a distal end and a proximal end, wherein the plurality of sensors are configured to sense along an axis extending between the distal and proximal ends of the force sensing device.

49. A medical endodevice comprising: an elongated liaising structure with a distal end; a force sensing device according to claim 35; and a camera located at a tip of the medical endodevice, wherein the force sensing device is mounted to the distal end of the elongated liaising structure such that the housing tip forms the tip of the medical endodevice.

50. The medical endodevice of claim 49, wherein the elongated liaising structure comprises an articulated portion, wherein the articulated portion of the elongated liaising structure comprises a plurality of bodies and angle sensors, each body being tiltably connected to another one of the plurality of bodies and each angle sensor being configured to determine an angle between two connected bodies, wherein each body is connected to another one of the plurality of bodies to be tiltable exclusively about one single axis.

51. The medical endodevice of claim 49, wherein the elongated liaising structure comprises a force/torque sensor unit being proximally spaced from the distal end.

52. The medical endodevice of claim 50, wherein the elongated liaising structure comprises a force/torque sensor unit being proximally spaced from the distal end, wherein the articulated portion of the elongated liaising structure has a distal end side and a proximal end side, the force sensing device is located distally of the articulated portion and the force/torque sensor unit is located proximally of the articulated portion.

53. The medical endodevice of claim 52, wherein the force/torque sensor unit of the elongated liaising structure comprises three unidirectional shaft force sensors stationarily spaced from each other; three shaft sensor actuators, each shaft sensor actuator being associated with one of the three unidirectional shaft force sensors; and a shaft spring element connecting the articulated portion of the elongated liaising structure to the three unidirectional shaft force sensors such that moving the articulated portion and the unidirectional shaft force sensors relative to each other causes a resilient deformation of the shaft spring element, wherein the shaft spring element is configured to arrange the articulated portion in a zero position relative to the unidirectional shaft force sensors by a spring force, and the shaft sensor actuators are coupled to the articulated portion such that moving the articulated portion out of the zero position, relative to the unidirectional shaft force sensors, causes at least one of the shaft sensor actuators to act on the associated unidirectional shaft force sensor.

54. A process of detecting a type of tissue, comprising: obtaining a medical endodevice according to claim 49; positioning the tip of the medical endodevice at a target tissue; moving the tip of the medical endodevice along the target tissue; obtaining sensor data generated by the plurality of sensors of the force sensing device of the medical endodevice; and determining a stiffness of the target tissue by evaluating the obtained sensor data of the plurality of sensors of the force sensing device.

55. The process of claim 54, further comprising: obtaining sensor data generated by a force/torque sensor unit of the endodevice; determining interactions along the endodevice by evaluating the sensor data of the force/torque sensor unit; and calculating disturbances acting on the endodevice by comparing the sensor data of the force/torque sensor unit with the sensor data of the plurality of sensors of the force sensing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] The force sensing device according to the invention, the medical endodevice according to the invention and the process according to the invention are described in more detail herein below by way of exemplary embodiments and with reference to the attached drawings, in which:

[0061] FIG. 1 shows a perspective exploded view of a first embodiment of a force sensing device according to the invention;

[0062] FIG. 2 shows a first side view of the force sensing device of FIG. 1;

[0063] FIG. 3 shows a second side view of the force sensing device of FIG. 1;

[0064] FIG. 4 shows a cross sectional view along the line A-A of the force sensing device of FIG. 2;

[0065] FIG. 5 shows a cross sectional view along the line B-B of the force sensing device of FIG. 3;

[0066] FIG. 6 shows a perspective exploded view of a second embodiment of a force sensing device according to the invention;

[0067] FIG. 7 shows a side view of the force sensing device of FIG. 6;

[0068] FIG. 8 shows a cross sectional view along the line A-A of the force sensing device of FIG. 7;

[0069] FIG. 9 shows a perspective exploded view of a third embodiment of a force sensing device according to the invention;

[0070] FIG. 10 shows a side view of the force sensing device of FIG. 9; and

[0071] FIG. 11 shows a cross sectional view along the line A-A of the force sensing device of FIG. 10.

DESCRIPTION OF EMBODIMENTS

[0072] In the following description certain terms are used for reasons of convenience and are not intended to limit the invention. The terms “right”, “left”, “up”, “down”, “under” and “above” refer to directions in the figures. The terminology comprises the explicitly mentioned terms as well as their derivations and terms with a similar meaning. Also, spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper”, “proximal”, “distal”, and the like, may be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. These spatially relative terms are intended to encompass different positions and orientations of the devices in use or operation in addition to the position and orientation shown in the figures. For example, if a device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be “above” or “over” the other elements or features. Thus, the exemplary term “below” can encompass both positions and orientations of above and below. The devices may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly. Likewise, descriptions of movement along and around various axes includes various special device positions and orientations.

[0073] To avoid repetition in the figures and the descriptions of the various aspects and illustrative embodiments, it should be understood that many features are common to many aspects and embodiments. Omission of an aspect from a description or figure does not imply that the aspect is missing from embodiments that incorporate that aspect. Instead, the aspect may have been omitted for clarity and to avoid prolix description. In this context, the following applies to the rest of this description: If, in order to clarify the drawings, a figure contains reference signs which are not explained in the directly associated part of the description, then it is referred to previous or following description sections. Further, for reason of lucidity, if in a drawing not all features of a part are provided with reference signs it is referred to other drawings showing the same part. Like numbers in two or more figures represent the same or similar elements.

[0074] FIG. 1 shows an exploded view of a first embodiment of a force sensing device 1 according to the invention to be implemented in a first embodiment of a medical endodevice according to the invention. The force sensing device 1 comprises a multi part housing 2 with a tip 21, an intermediate ring 22, a base 23 and two mounting screws 24. The tip 21 is essentially dome shaped and has a hemisphere portion 211 equipped with a central tensioner receptacle 213 having an opening, three actuator receptacles 212 having openings, and a camera opening 214. At its bottom end, the tip 21 has four downwardly extending axial projections 215 which are regularly distributed about a circumference of the bottom end.

[0075] The intermediate ring 22 has an internal geometry forming a socket bar receptacle 222 and two lateral screw through holes 223. Further, at its top end it is equipped with four regularly distributed axial recesses 221 which are upwardly open. The recesses 221 are shaped and positioned in correspondence with the projections 215 of the tip 21. The base 23 has two lateral screw sockets 232 at its top end for receiving the mounting screws 24 and a threaded connector 231 at its bottom end for being mounted to a liaising structure of the medical endodevice such that the force sensing device 1 establishes the tip of the endodevice.

[0076] The force sensing device 1 further comprises a sensor assembly 3, a vertically extending helical spring 4 of a spring element, a spring tensioning structure 5 and three actuator screws 6 as sensor actuators. The sensor assembly 3 comprises a printed circuit board (PCB) ring 32 with a central bore as support plate. On its top surface, the PCB ring 32 is equipped with three unidirectional force sensors 31 which are distributed in 120° angels towards each other on the PCB ring 32. Further, the PCB ring 32 has two lateral opposing through holes 321.

[0077] The spring tensioning structure 5 has a vertically extending tensioning screw 51, a socket bar 52 with a central screw socket 521 and a helical counter spring 53. The counter spring 53 is downwardly tapering, wherein its bottom end is dimensioned to lie on the socket bar 52 beneath the screw socket 521.

[0078] In FIGS. 2 and 3 the force sensing device 1 is sidewise shown in an assembled state, wherein in FIG. 2 it is turned by 90° about its vertical central axis compared to FIG. 3. As can be seen, the housing 2 surrounds and covers all other components of the force sensing device 1. The projections 215 of the tip 21 are positioned inside the recesses 221 of the intermediate ring 22. Thereby, the top end of the intermediate ring 22 and the bottom end of the tip 21 contact free inter-engage in a teeth like fashion. The openings of the actuator receptacles 212 and of the camera opening 214 are provided in the hemisphere 211 of the tip 21.

[0079] FIG. 4 shows a cross section of the force sensing device 1. Thereby, it can be seen that the PCB ring 32, the intermediate ring 22 and the base 23 are rigidly connected to each other by the mounting screws 24, which extend top down through the through holes 321 of the PCB ring 32 and of the intermediate ring 22, and are screwed into the screw sockets 232 of the base 23. Like this, the sensor assembly 3 is stationary to the intermediate ring 22 and the base 23.

[0080] The tip 21 of the housing 2 is mounted to the base 23 via the tensioning screw 51 extending through the helical spring 4 and being screwed into the screw socket 521 of the socket bar 52. The socket bar 52 is pressed to the base 52 by the counter spring 53 and the helical spring 4, which act on the counter bar 52 at its lower end and to the PCB ring 32 at its top end. The helical spring 4 extends centrally through the PCB ring 32 and through the counter spring 53. On its top side the helical spring 4 abuts from below at the tensioner receptacle 213 and at its bottom end at the top surface of the screw socket 521 of the socket bar 52. Thus, the more the tensioning screw 51 is screwed into the screw socket 521 the more the helical spring 4 is tensioned.

[0081] Since the tip 21 is connected to the base 23 via the helical spring 4, it can be moved to a certain extent in relation to the base 23 and, thus, the intermediate ring 22 and the PCB ring 32. Thereby, the projections 215 and recesses 221 limit the movement such that they define a maximum movability of the tip 21. Thus, the projections 215 and recesses 221 form safety and guiding structures of the force sensing device 1. Furthermore, the extent of tensioning the helical spring 4 by the tensioning screw 51 defines a resistance of the tip 21 with respect to movements. Like this, force sensibility of the force sensing device 1 can be defined.

[0082] In FIG. 5 another cross section of the force sensing device is shown. There, it can particularly be seen that each of the actuator screws 6 is associated top down to one of the force sensors 31. The force sensors 31 have an upwardly extending button which is adjacent to the lower end of the associated actuator screw 6. A length of the actuator screws 6 or their dimensions towards the force sensors 31 can be adjusted by screwing the actuator screws 6 more or less into the actuator receptacles 212. Thus, the actuator screws 6 can be adapted in accordance with the tensioning of the helical spring 4. In particular, their dimension can be adapted such that they are adjacent to the force sensors 31 without activating them when the helical spring 4 holds the tip 21 in an upright zero position. When the tip 21 is tilted or otherwise moved, for example by a tissue abutting the outer surface of the tip 21, the force sensor(s) 31 in the direction where the tip 21 is tilted are activated by pressing the button(s) more and more into the force sensor(s) 31.

[0083] The force sensing device 1 can be provided as the tip of the medical endodevice. This, in turn, can be used in a process of differentiating tissue types and detect contact forces (shear and normal forces). For this, the tip 21 of the medical endodevice is introduced into a body cavity and positioned at a target tissue or surface. Then, it is moved along the target tissue such that sensor data generated by the force sensors 31 of the force sensing device 1 of the medical endodevice are generated. By evaluating this sensor data the stiffness of the target tissue is determined (normal and shear components can be determined).

[0084] FIG. 6 shows an exploded view of a second embodiment of a force sensing device 10 according to the invention to be implemented in a second embodiment of a medical endodevice according to the invention. The force sensing device 10 comprises a multi part housing 20 with a tip 210, and a base 230. The tip 210 is essentially dome-shaped and has a hemisphere portion 2110 equipped with a central tensioner receptacle 2130 having an opening and a camera opening 2140. At its bottom end, the tip 210 has five downwardly extending axial projections 2150 which are regularly distributed about a circumference of the bottom end.

[0085] The base 230 is essentially cylindrical and has an internal geometry forming three inclined sensor abutting surfaces 2320. Further, at its top end it is equipped with five regularly distributed axial recesses 2310 which are upwardly open. The recesses 2310 are shaped and positioned in correspondence with the projections 2150 of the tip 210.

[0086] The force sensing device 10 further comprises a sensor assembly 30, a conical elastic body 40 of a spring element and a spring tensioning structure 50 having an axial vertical spring tensioning screw 510. The sensor assembly 30 comprises a flexible PCB 320 with a central bore portion 3210 and three inclined sensor carrier lamellas 3220 regularly extending from the central pore portion 3210 such that they are distributed in 120° angels towards each other. On their bottom surfaces, each of the sensor carrier lamellas 3220 is equipped with one unidirectional force sensor 310. The central bore portion 3210 is equipped with a central bore which is dimensioned to receive the spring tensioning screw 510 with clearance.

[0087] In addition to the spring tensioning screw 510, the spring tensioning structure 50 comprises a socket bar 520 with a central screw socket 5210, a helical counter spring 530 and a spring fixing ring 220. The counter spring 530 has a bottom end dimensioned to lie on the socket bar 520 beneath the screw socket 5210. The spring tensioning structure 50 predefines an upright zero position of the force sensing device 10.

[0088] In FIG. 7 the force sensing device 10 is shown in an assembled state from a side in its upright zero position. As can be seen, the housing 20 surrounds and covers all other components of the force sensing device 10. The projections 2150 of the tip 210 are positioned inside the recesses 2310 of the base 230. Thereby, the top end of the base 230 and the bottom end of the tip 210 contact free inter-engage in a teeth like fashion. The camera opening 2140 is provided in the hemisphere 2110 of the tip 210.

[0089] FIG. 8 shows a cross section of the force sensing device 10 along the line A-A depicted in FIG. 7. Thereby, it can be seen that the sensor abutting surfaces 2320 are inclined. More specifically, the for an angle of about 45° relative to an axis of the force sensing device 10 or to the spring tensioning screw 510. Depending on the specific application and the sensitivity aimed to be achieved in a particular direction this angle can be adapted. Correspondingly, the sensor carrier lamellas 3220 of the PCB 320 and the lower surface of the elastic body 40 are also inclined in the same manner. The force sensors 310 are downwardly oriented towards the sensor abutting surfaces 2320.

[0090] The tip 210 of the housing 20 is mounted to the base 230 via the tensioning screw 510 extending through the elastic body 40 and being screwed into the screw socket 5210 of the socket bar 520. The socket bar 520 is clamped in between the counter spring 530 and the fixing ring 220. The elastic body 40 is in connection with the sensor assembly 30 at its lower end and with the tip 210 at its top end. Thus, the more the tensioning screw 510 is screwed into the screw socket 5210, the more the elastic body 40 and the counter spring 530 are compressed and thereby tensioned. Hereby, the tip 210 is setup in a free floating way supported by pretensioned spring elements, i.e. the elastic body 40 and the counter spring 530, to receive forces in positive and negative directions for any of the force sensing directions.

[0091] Since the tip 210 is connected to the base 230 in quasi free floating manner via the elastic body 40, it can be moved to a certain extent in relation to the base 230. Thereby, the projections 2150 and recesses 2310 limit the movement such that they define a maximum movability of the tip 210. Thus, the projections 2150 and recesses 2310 form safety and guiding structures of the force sensing device 10. Furthermore, the extent of tensioning the elastic body 40 by the tensioning screw 510 defines a resistance of the tip 210 with respect to movements such as tilting, pulling, pushing or the like. Like this, force sensibility of the force sensing device 10 can be variably defined. Due to the flexibility of the PCB 320 a movement or tilting of the tip relative base 230 results in a smoothened pressure applied to the force sensors 310.

[0092] The force sensing device 10 can be provided as the tip of the medical endodevice. This, in turn, can be used in a process of differentiating tissue types and detect contact forces (shear and normal forces) as described above.

[0093] FIG. 9, FIG. 10 and FIG. 11 show an exploded view, a side view and a cross-sectional view of a third embodiment of a force sensing device 19 according to the invention to be implemented in a third embodiment of a medical endodevice according to the invention. The force sensing device 19 is similar to the second embodiment shown in FIGS. 6, 7 and 8. Where not described to be different in the following, the third embodiment of the force sensing device 19 is essentially identical to the second embodiment of the force sensing device 10 and it is referred to the respective description of FIGS. 6, 7 and 8 above.

[0094] Similar as the second force sensing device 10, the third force sensing device 19 comprises a multi part housing 29 with a tip 219 having a hemisphere portion 2119, a tensioner receptacle 2139 and a camera opening 2149, a base 239 having three inclined sensor abutting surfaces 2320 and five axial recesses 2310, and five downwardly extending axial projections 2159. The force sensing device 19 further comprises a sensor assembly 39 having three force sensors 319 and a flexible PCB 329 with a central bore portion 3219 and three inclined sensor carrier lamellas 3229, and a spring tensioning structure 59 having an axial vertical spring tensioning screw 519, a socket bar 529 with a central screw socket 5219, a helical counter spring 539 and a spring fixing ring 229.

[0095] Different from the second force sensing device 10, the third force sensing device 19 comprises a two part elastic element 49. More specifically, the elastic element 49 comprises a conical elastic body 419 and a helical tip spring 429. The tip spring 429 works together with the counter spring 539, to allow easier adaptation of the initial force range of the force sensing device 19 and its sensitivity. The tip spring 429 is positioned between the hemisphere portion 2119 of the tip 219 and the base 239. More specifically, it is arranged to force the tip 219 and the base 239 into a zero position predefined by the spring tensioning structure 59. The tip spring 429 is aligned to the elastic body 419, such that after a force is released, the tip spring 429 assists the force converting structure to get back to the initial or zero position faster. In particular, it can assist the elastic body 419 to efficiently get back its original shape or form once the force is released from the tip 219. While the force range of the three force sensors 319 stays the same or is given, the addition of the tip spring 429 allows adapting the force range of the force sensing device as a whole independent of the force range of the three force sensors 319. So, while the range of deformation of the elastic body 419 remains the same for any desired force range of the force sensing device 19, the tip spring 429 will ensure the transfer of additional forces directly to the base 239, providing a different force range for the force sensing device 10.

[0096] This description and the accompanying drawings that illustrate aspects and embodiments of the present invention should not be taken as limiting-the claims defining the protected invention. In other words, while the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Various mechanical, compositional, structural, electrical, and operational changes may be made without departing from the spirit and scope of this description and the claims. In some instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the invention. Thus, it will be understood that changes and modifications may be made by those of ordinary skill within the scope and spirit of the following claims. In particular, the present invention covers further embodiments with any combination of features from different embodiments described above and below.

[0097] The disclosure also covers all further features shown in the Figs. individually although they may not have been described in the afore or following description. Also, single alternatives of the embodiments described in the figures and the description and single alternatives of features thereof can be disclaimed from the subject matter of the invention or from disclosed subject matter. The disclosure comprises subject matter consisting of the features defined in the claims or the exemplary embodiments as well as subject matter comprising said features.

[0098] Furthermore, in the claims the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single unit or step may fulfil the functions of several features recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The terms “essentially”, “about”, “approximately” and the like in connection with an attribute or a value particularly also define exactly the attribute or exactly the value, respectively. The term “about” in the context of a given numerate value or range refers to a value or range that is, e.g., within 20%, within 10%, within 5%, or within 2% of the given value or range. Components described as coupled or connected may be electrically or mechanically directly coupled, or they may be indirectly coupled via one or more intermediate components. Any reference signs in the claims should not be construed as limiting the scope.