Source: https://patents.google.com/patent/US20140148836A1/en
Timestamp: 2018-12-12 00:48:52
Document Index: 523768732

Matched Legal Cases: ['Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61', 'Application No. 61']

US20140148836A1 - Mems debrider drive train - Google Patents
Mems debrider drive train Download PDF
US20140148836A1
US20140148836A1 US13843462 US201313843462A US2014148836A1 US 20140148836 A1 US20140148836 A1 US 20140148836A1 US 13843462 US13843462 US 13843462 US 201313843462 A US201313843462 A US 201313843462A US 2014148836 A1 US2014148836 A1 US 2014148836A1
US13843462
A medical device such as for removing tissue from a subject is provided with a distal housing configured with a tissue cutter assembly, an elongate member coupled to the distal housing and having an outer tube and an inner drive tube with a crown gear located on a distal end thereof, first and second rotatable members each rotatably mounted to the tissue cutter assembly, a first drive gear train coupled between the crown gear and the first rotatable member, and a second drive gear train coupled between the crown gear and the second rotatable member. The first and second drive gear trains are configured to drive the first and second rotatable members, respectively, in opposite directions. Concave and convex gear tooth profiles are also disclosed for improved performance of the first and second drive gear trains.
This application claims priority to U.S. Provisional Application No. 61/731,440 filed on Nov. 29, 2012.
This application is related to the following U.S. applications: application Ser. No. 13/007,578 filed Jan. 14, 2011; application Ser. No. 12/490,295 filed Jun. 23, 2009; Provisional Application No. 61/075,006 filed Jun. 23, 2008; Provisional Application No. 61/164,864 filed Mar. 30, 2009; Provisional Application No. 61/164,883 filed Mar. 30, 2009; application Ser. No. 12/490,301 filed Jun. 23, 2009; Provisional Application No. 61/075,006 filed Jun. 23, 2008; Provisional Application No. 61/164,883 filed Mar. 30, 2009; Provisional Application No. 61/408,558 filed Oct. 29, 2010; Provisional Application No. 61/710,608 filed Oct. 5, 2012; application Ser. No. 13/289,994 filed Nov. 11, 2011; application Ser. No. 13/659,734 filed Oct. 24, 2012; application Ser. No. 13/388,653 filed Apr. 16, 2012; application Ser. No. 12/491,220 filed on Jun. 24, 2009; application Ser. No. 13/535,197 filed Jun. 27, 2012; Application No. 61/731,434 filed Nov. 29, 2012 and application Ser. No. 13/714,285 filed on Dec. 13, 2012.
According to some aspects of the disclosure, a medical device for removing tissue from a subject is provided. One exemplary device includes a distal housing, an elongate member, first and second rotatable members, and first and second drive gear trains. The elongate member is coupled to the distal housing and is configured to introduce the distal housing to a target tissue site of the subject. The elongate member has an outer tube and an inner drive tube rotatably mounted within the outer tube. The inner drive tube has a crown gear located on a distal end thereof. The first rotatable member and the second rotatable member is each rotatably mounted to the tissue cutter assembly. The first and the second rotatable members each comprise a plurality of disc shaped blades. Each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member. Each of the plurality of blades of the first and the second rotatable members is directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces, and such that the first and the second rotatable members are configured to rotate and direct tissue into an interior portion of the distal housing. The first drive gear train is coupled between the crown gear and the first rotatable member. The first drive gear train comprises at least one spur gear. The second drive gear train is coupled between the crown gear and the second rotatable member. The second drive gear train comprises at least one spur gear. The first and the second drive gear trains are configured to drive the first and the second rotatable members, respectively, in opposite directions.
In some of the above embodiments, the first and the second drive gear trains each comprise two separate spur gears. The two separate spur gears of the first drive gear train may be arranged in a symmetrical fashion relative to the two separate spur gears of the second drive gear train.
In some embodiments, the tissue cutter assembly is fabricated separately from the distal housing and subsequently assembled therewith. The tissue cutter assembly may be formed at least in part by an additive process, and the distal housing may be formed at least in part by a subtractive process.
In some embodiments, the elongate member includes an annular void formed between the inner drive tube and the outer tube. In these embodiments, the device is configured to have irrigation fluid flow distally through the annular void, through the tissue cutter assembly, and then carry cut tissue pieces proximally though the inner drive tube.
According to other aspects of the disclosure, a medical device for removing tissue from a subject is provided with a distal housing, an elongate member, first and second rotatable members, and a first drive gear train. In these embodiments, the distal housing is configured with a tissue cutter assembly. The elongate member is coupled to the distal housing and is configured to introduce the distal housing to a target tissue site of the subject. The elongate member has an outer tube and an inner drive tube rotatably mounted within the outer tube. The inner drive tube has a crown gear located on a distal end thereof and comprises a plurality of gear teeth. The inner drive tube has an outer diameter no greater than 12 mm and no smaller than 0.5 mm. The first rotatable member and the second rotatable member are each rotatably mounted to the tissue cutter assembly. The first and the second rotatable members each include a plurality of disc shaped blades. Each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member. Each of the plurality of blades of the first and the second rotatable members is directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces, and such that the first and the second rotatable members are configured to rotate in opposite directions to direct tissue into an interior portion of the distal housing. The first drive gear train is coupled between the crown gear and the first rotatable member. The first drive gear train includes a first spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear. The first spur gear is configured to rotate about an axis that is not parallel to an axis of rotation of the crown gear. The crown gear teeth have a convex profile and the first spur gear teeth have a concave profile.
In some of the above embodiments, the crown gear teeth have a mid-point base thickness that is greater than a base thickness of the first spur gear teeth. In some embodiments, the ratio of the first spur gear teeth mid-point base thickness to the crown gear teeth mid-point base thickness is in the range of 0.6 to 0.9. In some embodiments, the ratio is about 0.76.
In some embodiments, the first drive gear train includes a second spur gear coupled between the first spur gear and the first rotatable member. In these embodiments, the second spur gear has teeth with a convex profile. The second spur gear teeth may have a mid-point base thickness that is greater than a mid-point base thickness of the first spur gear teeth. In some embodiments, the ratio of the first spur gear teeth mid-point base thickness to the second spur gear teeth mid-point base thickness is in the range of 0.4 to 0.95. In some embodiments the ratio is about 0.85. In some embodiments, a tangent to a mid-point base thickness of the teeth of the second spur gear slopes towards a tip of the teeth of the second spur gear. Alternatively, a tangent to a mid-point base thickness of the teeth of the second spur gear may slope away from a tip of the teeth of the second spur gear to create a bulging tip section of the teeth of the second spur gear to reduce backlash between the teeth of second spur gear and the teeth of the first spur gear. The ratio of the first spur gear teeth mid-point base thickness to the second spur gear teeth mid-point base thickness may be in the range of 0.6 to 0.9. In some embodiments, the ratio is about 0.77.
In some embodiments, the crown gear teeth have opposing side surfaces that taper towards a center point of the inner drive tube. Both the first and the second rotatable members may be driven by the first drive gear train. Alternatively, the device may include a second drive gear train coupled between the crown gear and the second rotatable member. In such embodiments, the second drive gear train includes a second spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear. The second spur gear is configured to rotate about an axis that is not parallel to an axis of rotation of the crown gear. The second spur gear teeth have a concave profile.
According to aspects of the disclosure, a medical device for removing tissue from a subject is provided with a distal housing, an elongate member, first and second rotatable members, and first and second drive gear trains. In these embodiments, the distal housing is configured with a tissue cutter assembly. The elongate member is coupled to the distal housing and is configured to introduce the distal housing to a target tissue site of the subject. The elongate member has an outer tube and an inner drive tube rotatably mounted within the outer tube. The inner drive tube has a crown gear located on a distal end thereof and includes a plurality of gear teeth. The crown gear teeth have opposing side surfaces that taper towards a center point of the inner drive tube. The inner drive tube has an outer diameter no greater than 12 mm and no smaller than 0.5 mm. The first rotatable member and the second rotatable member are each rotatably mounted to the tissue cutter assembly. The first and the second rotatable members each include a plurality of disc shaped blades. Each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member. Each of the plurality of blades of the first and the second rotatable members is directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces, and such that the first and the second rotatable members are configured to rotate in opposite directions to direct tissue into an interior portion of the distal housing. The first drive gear train is coupled between the crown gear and the first rotatable member. The first drive gear train includes a first spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a second spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the first spur gear. The first and the second spur gears are configured to rotate about axes that are perpendicular to an axis of rotation of the crown gear. The crown gear teeth and the second spur gear teeth have a convex profile and the first spur gear teeth have a concave profile. The crown gear teeth and the second spur gear teeth have a mid-point base thickness that is greater than a base thickness of the first spur gear teeth. The second drive gear train is coupled between the crown gear and the second rotatable member. The second drive gear train includes a third spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a fourth spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the third spur gear. The third and the fourth spur gears are configured to rotate about axes that are perpendicular to the axis of rotation of the crown gear. The fourth spur gear teeth have a convex profile and the third spur gear teeth have a concave profile. The crown gear teeth and the fourth spur gear teeth have a mid-point base thickness that is greater than a base thickness of the third spur gear teeth.
In some embodiments, a tangent to a mid-point base thickness of the teeth of the second spur gear slopes away from a tip of the teeth of the second spur gear to create a bulging tip section of the teeth of the second spur gear to reduce backlash between the teeth of second spur gear and the teeth of the first spur gear. In these embodiments, a tangent to a mid-point base thickness of the teeth of the fourth spur gear slopes away from a tip of the teeth of the fourth spur gear to create a bulging tip section of the teeth of the fourth spur gear to reduce backlash between the teeth of fourth spur gear and the teeth of the third spur gear.
FIG. 8 is a perspective view showing another exemplary embodiment of a cutter head assembly.
FIG. 9 is a perspective view showing the inner components of the cutter head assembly of FIG. 8 with solid lines and the outer components with phantom lines.
FIG. 10 is a similar view to FIG. 9 showing the cutter head assembly in a cross-sectional view taken along the longitudinal centerline of the device.
FIG. 11 is an exploded perspective view showing the components of the cutter head assembly of FIG. 8.
FIG. 12 is an enlarged perspective view showing the lug housing of the cutter head assembly of FIG. 8.
FIG. 13 is a perspective view showing the first and second drive gear trains of the cutter head assembly of FIG. 8.
FIG. 14 is a perspective view showing fluid flow paths of the cutter head assembly of FIG. 8.
FIG. 15A is a plan view showing gear teeth profiles of a pair of conventional involute gear teeth.
FIG. 15B is a plan view showing gear teeth profiles of a pair of concave and convex gear teeth.
FIG. 16A is radially inward plan view showing portions of two intermeshing gears having conventional involute gear teeth.
FIG. 16B is radially inward plan view showing portions of two intermeshing gears having concave and convex gear teeth.
FIG. 17 is a perspective view showing a first drive gear train having three gears with concave and convex gear teeth.
FIG. 18A is a perspective view showing a crown gear located on the distal end of an inner drive tube.
FIG. 18B is an end view showing the crown gear of FIG. 18A.
FIG. 19 is a perspective view showing a single gear drive train load path formed between two crown gears, each formed on an end of a drive tube.
FIG. 20 is a perspective view showing a dual load path gear drive train using spur gears, each coupled between two crown gears.
FIG. 21A is a side plan view showing a gear tooth having a concave profile.
FIG. 21B is a side plan view showing a gear tooth having a convex profile and configured to mate with the gear tooth of FIG. 21A.
FIG. 21C is a side plan view showing the gear tooth of FIG. 21A.
FIG. 21D is a side plan view showing the gear tooth of FIG. 21B.
FIG. 22A is a side plan view showing the gear tooth of FIG. 21A.
FIG. 22B is a side plan view showing a gear tooth having a convex profile and configured to mate with the gear tooth of FIG. 22A.
FIG. 22C is a side plan view showing the gear tooth of FIG. 22A.
FIG. 22D is a side plan view showing the gear tooth of FIG. 22B.
FIG. 23A is a side plan view showing the gear tooth of FIG. 21A.
FIG. 23B is a side plan view showing a gear tooth having a convex profile and configured to mate with the gear tooth of FIG. 23A.
FIG. 23C is a side plan view showing the gear tooth of FIG. 23A.
FIG. 23D is a side plan view showing the gear tooth of FIG. 23B.
FIG. 24 is an enlarged plan view showing the gear tooth of FIG. 21A.
FIG. 25 is an enlarged plan view showing the gear tooth of FIG. 21B.
FIG. 26 is an enlarged plan view showing the gear tooth of FIG. 22B.
FIG. 27 is an enlarged plan view showing the gear tooth of FIG. 23B.
In some embodiments, it is desired to define a shearing thickness as the gap between elements as they move past one another. Such gaps may be defined by layer thickness increments or multiples of such increments or by the intralayer spacing of elements as they move past one another. In some embodiments, shearing thickness of blades passing blades or blades moving past interdigitated fingers, or the like may be optimally set in the range of 2-100 microns or some other amount depending on the viscosity or other parameters of the materials being encountered and what the interaction is to be (e.g. tearing, shredding, transporting, or the like). For example for shredding or tearing tissue, the gap may be in the range of 2-10 microns, or in some embodiments in the range of 4-6 microns.
Referring to FIGS. 8-14, another exemplary embodiment of a cutter head assembly 810 is shown. As seen in FIG. 8, device 810 is similar in design to previously described cutter head assembly 5332 shown in FIGS. 6A-6C. Similar to device 5332, device 810 includes a lug 812 provided with a transverse slot 814 (best seen in FIG. 12) at its distal end for receiving a rotor housing assembly 816. Rotor housing assembly 816 includes a first rotatable member 818 and a second rotatable member 820. The proximal end of lug 812 is configured to mate with the distal end of a bearing housing 822, or directly with the distal end of an outer support tube (not shown). Inner drive tube 824 is slidably received within the outer support tube and bearing housing 822, if provided, to drive cutter head assembly 810.
FIG. 9 is a perspective view showing the inner components of cutter head assembly 810 with solid lines and the outer components with phantom lines. FIG. 10 is a similar view to FIG. 9 but shows device 810 in a cross-sectional view taken along the longitudinal centerline of device 810. FIG. 11 is an exploded perspective view of device 810. As will now be described in reference to FIGS. 9-11, device 810 includes two separate gear drive trains. The first gear drive train is configured to drive first rotatable member 818 and the second gear drive train is configured to drive second rotatable member 820.
In this exemplary embodiment, the first gear drive train includes a large spur gear 826 and a small spur gear 828 to drive the first rotatable member 818. In a mirror image of the first gear drive train, the second gear drive train includes a large spur gear 830 and a small spur gear 832 to drive the second rotatable member 820. Large spur gear 826 is rotatably mounted within an annular recess 834 on top of lug 812, as best seen in FIG. 12. A portion of large spur gear 826 extends proximally into the interior of lug 812 to mesh with a crown gear 836 located on the distal end of inner drive tube 824, as best seen in FIG. 9. As with previous embodiments, large spur gear 826 rotates about an axis that is perpendicular to the axis of crown gear 836. Small spur gear 828 is rotatably mounted within recess 838 on top of lug 812, as best seen in FIG. 12. Small spur gear 828 is configured to mesh with and be driven by large spur gear 826. Large spur gear 830 and small spur gear 832 of the second gear drive train are received in similar recesses in the bottom of lug 812 (not shown), and operate in a manner identical to that of large spur gear 826 and small spur gear 828 of the first gear drive train.
In this exemplary embodiment, small spur gear 828 is provided with a triangular recess through its center of rotation. First rotatable member 818 is similarly provided with a triangular recess through its center of rotation. Gear pin 840 as a triangular cross-section configured to be slidably received through the triangular recesses of small spur gear 828 and first rotatable member 818. With this arrangement, small spur gear 828 rotatably drives first rotatable member 818 through gear pin 840. A bearing spacer 842, also having with a triangular recess through its center of rotation, may be provided for supporting gear pin 840. A bearing spacer recess 844 may be provided in lug 812 at the bottom of recess 838, as best seen in FIG. 12, for slidably receiving bearing spacer 842 and allowing it to rotate with respect to lug 812. This allows bearing spacer 842 to reside between the bottom of small spur gear 828 and the top of rotor housing assembly 816. A pin aligner cap 846 may also be provided for supporting gear pin 840. Pin aligner cap 846 includes a central recess configured to slidably receive a reduced diameter lower end of gear pin 840, and an outer bushing surface configured to radially support the lower end of gear pin 840 as pin aligner cap 846 spins within circular recess 848 (best seen in FIG. 12) in lug 812.
In a symmetrical fashion to the first gear drive train, large spur gear 830 and small spur gear 832 of the second gear drive train are rotatably mounted within the bottom of lug 812. A second gear pin 840, bearing spacer 842 and pin aligner cap 846 are provided to secure small spur gear 832 within similar recesses in lug 812 and to allow it to drive second rotatable member 820. Top cover 850 is provided to retain large spur gear 826 and the enlarged head of gear pin 840 of the first gear drive train, and the enlarged head of pin aligner cap 846 of the second gear drive train. In a similar fashion, bottom cover 852 is provided to retain large spur gear 830 and the enlarged head of gear pin 840 of the second gear drive train, and the enlarged head of pin aligner cap 846 of the first gear drive train. Top cover 850 and bottom cover 852 may be configured to be slightly different as shown, or may be configured to be identical so that the entire cutter head assembly 810 is symmetrical about its central axis. Top cover 850 and bottom cover 852 may be press fit, glued or welded in place, or fastened to lug 812 in another suitable manner.
A thrust bearing 854 may be slid over at the distal end of inner drive tube 824 and welded in place to axially constrain crown gear 836 of inner drive tube 824 relative to bearing housing 822 and lug 812. Thrust bearing 854 may include forward and/or rearward thrust surfaces that bear against mating surfaces within the central bore of bearing housing 822. Irrigation channels 856 (best seen in FIG. 11) may be provided on the inner and outer surfaces of thrust bearing 854 to allow a fluid to pass distally therethrough for lubricating and cooling the moving parts of device 810, and for flushing cut tissue pieces from the target tissue. Similar irrigation channels 858 (best seen in FIG. 12) may be provided axially along the central bore of lug 812.
Referring to FIG. 13, operation of the first and second gear drive trains will be described. For clarity, only the basic components of the two gear drive trains and a single cutting blade from each of the two rotatable members is shown in FIG. 13. Crown gear 836 on the distal end of inner drive tube 824 may be rotated in the counterclockwise direction (as viewed when looking in the proximal direction), as shown by the arrows around inner drive tube 824. This rotates large spur gear 826 of the first gear drive train in the counterclockwise direction (as viewed from above), and rotates large spur gear 830 of the second gear drive train in the opposite, clockwise direction, as shown by the arrows around those two gears. Large spur gear 826 of the first gear drive train in turn drives small spur gear 826, gear pin 840 and the cutting blade of first rotatable member 818 in the clockwise direction, as shown by the arrows around those components. Similarly, large spur gear 830 of the second gear drive train in turn drives small spur gear 832, gear pin 840 and the cutting blade of the second rotatable member 820 in the opposite, counterclockwise direction, as shown by the arrows around those components. This arrangement drives the tissue cutting blades of the first rotatable member 818 and the second rotatable member 820 in opposite directions so that tissue may be sheared therebetween. In this embodiment, each of the two gear drive trains having two spur gears allows the drive trains to reach between crown gear 836 and its associated rotatable member 818 or 820. In other embodiments (not shown), a single spur gear or more than two spur gears per drive train may be used to couple crown gear 836 to the rotatable members 818 and 820. In some embodiments, one of the drive trains may be configured with a different number or size of gears than the other drive train.
Referring to FIG. 14, fluid flow through cutter head assembly 810 will be described. As with previously described embodiments, a fluid reservoir located at the proximal end of the instrument (not shown) provides fluid to the distal end of the instrument through an annular void located between inner drive tube 824 and the outer support tube and bearing housing 822 (not shown in FIG. 14). This fluid flow is depicted by arrow 860. Fluid then flows inwardly over the planar surfaces of large spur gears 826 and 830, as shown by arrows 862, and also flows around the central bores and outer teeth of those gears as shown. Fluid also flows around the central bores and outer teeth of small spur gears 828 and 832 as shown. As depicted by arrows 864, fluid also flows out of the side of rotor housing assembly 816, and flushes tissue debris from the target tissue site. This fluid returns back into the rotor housing assembly 816 through its center with the tissue debris, and up through the central bore of the inner drive tube 824, as shown by arrows 866.
The above-described arrangement provides a dual load path between inner drive tube 824 and each of the rotatable members 818 and 820. This allows critical load points, such as gear teeth and bearing surfaces, to receive half or less of the loads they might otherwise need to carry. With the very small feature sizes, high-speeds and high tissue cutting loads involved with the inventive tissue cutting devices disclosed herein, such load reduction can make the difference between a medical instrument that can reliably operate for hours and one that quickly fails. This is particularly true in instruments that need to reverse direction quickly and experience high impact loading.
Referring now to FIGS. 15-27, further details of the previously described dual gear drive trains will be described. Some of these features may be utilized in single gear drive train arrangements and in other applications, as will also be described. Referring first to FIG. 15A, a conventional pair 910 of inter-engaging involute gear teeth 912 is shown. These involute gear teeth may be located on crown gear 836, large spur gears 826, 830, and/or on small spur gears 828, 832. The Applicants of this application have discovered however, that by modifying these gear teeth profiles, more durable gears can be created for these particular applications. In particular, Applicants have discovered that by creating an inter-meshing gear pair having one set of teeth with convex profiles, and another set of teeth with concave profiles, micro-gear trains can be created having improved operating characteristics such as higher load capabilities, higher ranges of operating speeds, reduced backlash and/or less gear wear.
FIG. 15B shows an example of an improved intermeshing gear pair 914 having one concave tooth 916 and one convex tooth 918. As can be seen by comparing FIGS. 15A and 15B, gear pair 914 can provide a greater area of contact between the intermeshing gear teeth, and can keep gear loads from being focused on the tips of the gear teeth. In some embodiments of a dual load path cutter head assembly 810 as shown in FIG. 814, the crown gear 836 and the small spur gears 828 and 832 may be provided with convex gear teeth 918, while large spur gears 826 and 830 are provided with concave gear teeth 916. In other embodiments, crown gear 836 and the small spur gears 828 and 832 may be provided with concave gear teeth 916, while large spur gears 826 and 830 are provided with convex gear teeth 918.
FIG. 16A shows a sequence of non-optimized rotating gears. In each of the steps 1-4, large spur gear 826 is shown above, intermeshing with crown gear 836 below. In this sequence, the gears are not properly matched. In step 1, the exiting tooth on the right of large spur gear 826 can be seen crashing into the corresponding tooth of crown gear 836.
FIG. 16B shows a sequence of optimized rotating gears. Is the steps 1-4, large spur gear 826 is shown above, intermeshing with crown gear 836 below. In this sequence, the gears are properly matched according to aspects of this disclosure. In step 1, the exiting gear tooth on the right does not crash and the middle gear tooth can be seen coming into full contact with the corresponding tooth of large spur gear 826. Note that the teeth of crown gear 836 have a convex profile while the teeth of the large spur gear 826 have a concave profile.
FIG. 17 shows a single gear drive train having a crown gear 836, large spur gear 826 and small spur gear 828. As shown, the teeth of crown gear 836 have a convex profile, the mating teeth of large spur gear 826 have a concave profile, and the teeth of the small spur gear 828 have a concave profile.
FIGS. 18A and 18B are a perspective view and an end view, respectively, showing crown gear 836 on the distal end of inner drive tube 824. As shown by the radial lines extending from the opposite surfaces of one of the gear teeth in each figure, the teeth of crown gear 836 are tapered such that each portion of a tooth surface is aligned with a point on the central axis of rotation 920 of inner drive tube 824. This inwardly tapered tooth profile assists in allowing the exiting teeth of large spur gear 826 to transition away from the teeth of crown gear 836 without crashing. These teeth may be formed with a laser cutter that cuts on center from two-dimensional data as tube 824 rotates about its central axis 920.
FIG. 19 shows a single gear drive train load path formed between two crown gears 836, each formed on an end of a drive tube 824. FIG. 20 shows a dual load path gear drive train using spur gears 826, each coupled between crown gears 836. Each of these arrangements allows for driving an end effector of a medical device having a sharp bend or articulation point in its shaft. This provides a significant improvement over the prior art in which only large sweeps of an instrument's shaft have been provided through the use of a gradually bent outer tube and a flexible inner tube. These new arrangements allow for instrument constructs that enable a surgeon to reach points “kicked” off to the side at the end of a straight access passage.
FIGS. 21-27 show additional details of the previously described gear tooth profiles. Referring first to FIG. 21, views A and C show a gear tooth 922 having a concave profile, and views B and D show a mating gear tooth 924 having a convex profile. In some embodiments, large spur gears 826 and 830 are provided with concave teeth 922, and crown gear 836 is provided with convex gear teeth 924 for driving concave teeth 922. Concave teeth 922 can be partially defined by a tooth height h1 between the tips of the gear teeth and the root circle. At a height halfway between the root circle and the tips of the teeth (0.5 h1), a base thickness or width “a” of concave tooth 922 can be defined, as shown. Similarly, convex teeth 924 can be partially defined by a tooth height h2 between the tips of the gear teeth and the root circle. At a height halfway between the root circle and the tips of the teeth (0.5 h2), a base thickness or width “b” of convex tooth 924 can be defined, as shown. In some embodiments, the ratio a/b between the base thickness of concave tooth 922 and the base thickness of convex tooth 924 is 0.76. In some embodiments, the ratio a/b is in a range of 0.6 to 0.9. Views C and D of FIG. 21 show that for both concave tooth 922 and convex tooth 924, a tangent to the tooth surface at the base thickness slopes upward and towards the tip of the tooth. Concave gear tooth profile 922 shown in views A and C of FIG. 21 can be considered concave because it has a convex to concave inflection point located between the tip of the tooth and the base thickness (i.e. on the upper half of the gear tooth).
Referring now to FIG. 22, views A and C again show gear tooth 922 with its concave profile, and views B and D show a mating gear tooth 926 having a convex profile that is different than the convex profile of gear tooth 924 shown in FIGS. 21B and 21D. In some embodiments, large spur gears 826 and 830 are provided with concave teeth 922, and small spur gears 828 and 832 are provided with convex gear teeth 926, which are driven by concave teeth 922. Convex teeth 926 can be partially defined by a tooth height h2 between the tips of the gear teeth and the root circle. At a height halfway between the root circle and the tips of the teeth (0.5 h2), a base thickness or width “b” of convex tooth 926 can be defined, as shown. In some embodiments, the ratio a/b between the base thickness of concave tooth 922 and the base thickness of convex tooth 926 is 0.85. In some embodiments, the ratio a/b is in a range of 0.4 to 0.95. Views C and D of FIG. 22 show that for both concave tooth 922 and convex tooth 926, a tangent to the tooth surface at the base thickness slopes upward and towards the tip of the tooth. It can be noted that the tangent line shown in FIG. 22D for tooth 926 has a steeper angle than the tangent line shown in FIG. 21D for tooth 924.
Referring now to FIG. 23, views A and C again show gear tooth 922 with its concave profile, and views B and D show a mating gear tooth 928 having a convex profile that is different than the convex profile of gear tooth 924 shown in FIGS. 21B and 21D and gear tooth 926 shown in FIGS. 22B and 22D. In some embodiments, large spur gears 826 and 830 are provided with concave teeth 922, and small spur gears 828 and 832 are provided with convex gear teeth 928, which are driven by concave teeth 922. Convex teeth 928 can be partially defined by a tooth height h2 between the tips of the gear teeth and the root circle. At a height halfway between the root circle and the tips of the teeth (0.5 h2), a base thickness or width “b” of convex tooth 928 can be defined, as shown. In some embodiments, the ratio a/b between the base thickness of concave tooth 922 and the base thickness of convex tooth 928 is 0.77. In some embodiments, the ratio a/b is in a range of 0.6 to 0.9. The View C of FIG. 23 shows that for concave tooth 922, a tangent to the tooth surface at the base thickness slopes upward and towards the tip of the tooth, but view D of FIG. 23 shows that for convex tooth 928, a tangent to the tooth surface at the base thickness slopes upward and away from the tip of the tooth. The more bulbous top portion of gear tooth 928 provides for increased anti-backlash between gear teeth 928 and 922. Convex gear tooth profile 928 shown in views B and D of FIG. 23 cannot be considered concave because it does not have a convex to concave inflection point located between the tip of the tooth and the base thickness (i.e. on the upper half of the gear tooth). On the contrary, such an inflection point only occurs between the base thickness and the root of the tooth (i.e. on the lower half of the gear tooth).
FIG. 24 is an enlarged view of concave gear tooth 922 of FIG. 21A. FIG. 25 is an enlarged view of convex gear 924 of FIG. 21B. FIG. 26 is an enlarged view of convex gear 926 of FIG. 22B. FIG. 27 is an enlarged view of convex gear 928 of FIG. 23B.
As described above, in some embodiments the gear train comprises a first convex gear driving a first concave gear, which in turn drives a second convex gear. In other embodiments, the second convex gear in such a gear train can drive a second concave gear, or the second convex gear can be omitted leaving just the first convex gear driving the first concave gear. Similarly, in some embodiments the gear train comprises a first concave gear driving a first convex gear, which in turn drives a second concave gear. In other embodiments, the second concave gear in such a gear train can drive a second convex gear, or the second concave gear can be omitted leaving just the first concave gear driving the first convex gear.
an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject, the elongate member having an outer tube, an inner drive tube rotatably mounted within the outer tube, the inner drive tube having a crown gear located on a distal end thereof;
a first rotatable member and a second rotatable member each rotatably mounted to the tissue cutter assembly, the first and the second rotatable members each comprising a plurality of disc shaped blades, wherein each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member, each of the plurality of blades of the first and the second rotatable members being directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces and such that the first and the second rotatable members are configured to rotate and direct tissue into an interior portion of the distal housing;
a first drive gear train coupled between the crown gear and the first rotatable member, the first drive gear train comprising at least one spur gear; and
a second drive gear train coupled between the crown gear and the second rotatable member, the second drive gear train comprising at least one spur gear,
wherein the first and the second drive gear trains are configured to drive the first and the second rotatable members, respectively, in opposite directions.
2. The medical device of claim 1, wherein the first and the second drive gear trains each comprise two separate spur gears.
3. The medical device of claim 2, wherein the two separate spur gears of the first drive gear train are arranged in a symmetrical fashion relative to the two separate spur gears of the second drive gear train.
4. The medical device of claim 1, wherein the tissue cutter assembly is fabricated separately from the distal housing and subsequently assembled therewith.
5. The medical device of claim 4, wherein the tissue cutter assembly is formed at least in part by an additive process, and wherein the distal housing is formed at least in part by a subtractive process.
6. The medical device of claim 1, wherein the elongate member comprises an annular void formed between the inner drive tube and the outer tube, and wherein the device is configured to have irrigation fluid flow distally through the annular void, through the tissue cutter assembly, and then carry cut tissue pieces proximally though the inner drive tube.
7. A medical device for removing tissue from a subject, comprising:
an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject, the elongate member having an outer tube, an inner drive tube rotatably mounted within the outer tube, the inner drive tube having a crown gear located on a distal end thereof and comprising a plurality of gear teeth, the inner drive tube having an outer diameter no greater than 12 mm and no smaller than 0.5 mm;
a first rotatable member and a second rotatable member each rotatably mounted to the tissue cutter assembly, the first and the second rotatable members each comprising a plurality of disc shaped blades, wherein each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member, each of the plurality of blades of the first and the second rotatable members being directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces and such that the first and the second rotatable members are configured to rotate in opposite directions to direct tissue into an interior portion of the distal housing; and
a first drive gear train coupled between the crown gear and the first rotatable member, the first drive gear train comprising a first spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear, the first spur gear being configured to rotate about an axis that is not parallel to an axis of rotation of the crown gear,
wherein the crown gear teeth have a convex profile and the first spur gear teeth have a concave profile.
8. The medical device of claim 7, wherein the crown gear teeth have a mid-point base thickness that is greater than a base thickness of the first spur gear teeth.
9. The medical device of claim 8, wherein the ratio of the first spur gear teeth mid-point base thickness to the crown gear teeth mid-point base thickness is in the range of 0.6 to 0.9.
10. The medical device of claim 9, wherein the ratio is about 0.76.
11. The medical device of claim 7, wherein the first drive gear train comprises a second spur gear coupled between the first spur gear and the first rotatable member, the second spur gear having teeth with a convex profile.
12. The medical device of claim 11, wherein the second spur gear teeth have a mid-point base thickness that is greater than a mid-point base thickness of the first spur gear teeth.
13. The medical device of claim 12, wherein the ratio of the first spur gear teeth mid-point base thickness to the second spur gear teeth mid-point base thickness is in the range of 0.4 to 0.95.
14. The medical device of claim 13, wherein the ratio is about 0.85.
15. The medical device of claim 12, wherein a tangent to a mid-point base thickness of the teeth of the second spur gear slopes towards a tip of the teeth of the second spur gear.
16. The medical device of claim 12, wherein a tangent to a mid-point base thickness of the teeth of the second spur gear slopes away from a tip of the teeth of the second spur gear to create a bulging tip section of the teeth of the second spur gear to reduce backlash between the teeth of second spur gear and the teeth of the first spur gear.
17. The medical device of claim 16, wherein the ratio of the first spur gear teeth mid-point base thickness to the second spur gear teeth mid-point base thickness is in the range of 0.6 to 0.9.
18. The medical device of claim 17, wherein the ratio is about 0.77.
19. The medical device of claim 7, wherein the crown gear teeth have opposing side surfaces that taper towards a center point of the inner drive tube.
20. The medical device of claim 7, wherein both the first and the second rotatable members are driven by the first drive gear train.
21. The medical device of claim 7, further comprising a second drive gear train coupled between the crown gear and the second rotatable member, the second drive gear train comprising a second spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear, the second spur gear being configured to rotate about an axis that is not parallel to an axis of rotation of the crown gear, wherein the second spur gear teeth have a concave profile.
22. A medical device for removing tissue from a subject, comprising:
an elongate member coupled to the distal housing and configured to introduce the distal housing to a target tissue site of the subject, the elongate member having an outer tube, an inner drive tube rotatably mounted within the outer tube, the inner drive tube having a crown gear located on a distal end thereof and comprising a plurality of gear teeth, wherein the crown gear teeth have opposing side surfaces that taper towards a center point of the inner drive tube, the inner drive tube having an outer diameter no greater than 12 mm and no smaller than 0.5 mm;
a first rotatable member and a second rotatable member each rotatably mounted to the tissue cutter assembly, the first and the second rotatable members each comprising a plurality of disc shaped blades, wherein each of the plurality of blades of the first rotatable member lies in a plane parallel to and axially offset from a plane of another of the blades of the first rotatable member, each of the plurality of blades of the first and the second rotatable members being directly adjacent to at least one parallel surface and positioned to partially overlap the adjacent parallel surface such that tissue may be sheared between the adjacent, overlapping blades and parallel surfaces and such that the first and the second rotatable members are configured to rotate in opposite directions to direct tissue into an interior portion of the distal housing;
a first drive gear train coupled between the crown gear and the first rotatable member, the first drive gear train comprising a first spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a second spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the first spur gear, the first and the second spur gears being configured to rotate about axes that are perpendicular to an axis of rotation of the crown gear, wherein the crown gear teeth and the second spur gear teeth have a convex profile and the first spur gear teeth have a concave profile, wherein the crown gear teeth and the second spur gear teeth have a mid-point base thickness that is greater than a base thickness of the first spur gear teeth; and
a second drive gear train coupled between the crown gear and the second rotatable member, the second drive gear train comprising a third spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the crown gear and a fourth spur gear having a plurality of gear teeth arranged to mesh with the gear teeth of the third spur gear, the third and the fourth spur gears being configured to rotate about axes that are perpendicular to the axis of rotation of the crown gear, wherein the fourth spur gear teeth have a convex profile and the third spur gear teeth have a concave profile, wherein the crown gear teeth and the fourth spur gear teeth have a mid-point base thickness that is greater than a base thickness of the third spur gear teeth.
23. The medical device of claim 22, wherein a tangent to a mid-point base thickness of the teeth of the second spur gear slopes away from a tip of the teeth of the second spur gear to create a bulging tip section of the teeth of the second spur gear to reduce backlash between the teeth of second spur gear and the teeth of the first spur gear, and wherein a tangent to a mid-point base thickness of the teeth of the fourth spur gear slopes away from a tip of the teeth of the fourth spur gear to create a bulging tip section of the teeth of the fourth spur gear to reduce backlash between the teeth of fourth spur gear and the teeth of the third spur gear.
US13843462 2012-11-29 2013-03-15 Mems debrider drive train Abandoned US20140148836A1 (en)
US201261731440 true 2012-11-29 2012-11-29
US13843462 US20140148836A1 (en) 2012-11-29 2013-03-15 Mems debrider drive train
EP20130858635 EP2925241A4 (en) 2012-11-29 2013-11-26 Mems debrider drive train
PCT/US2013/071874 WO2014085389A1 (en) 2012-11-29 2013-11-26 Mems debrider drive train
US15943598 US20180289385A1 (en) 2008-06-23 2018-04-02 Surgical Micro-Shears and Methods of Fabrication and Use
US20140148836A1 true true US20140148836A1 (en) 2014-05-29
ID=50773902
US13843462 Abandoned US20140148836A1 (en) 2012-11-29 2013-03-15 Mems debrider drive train
US (1) US20140148836A1 (en)
EP (1) EP2925241A4 (en)
WO (1) WO2014085389A1 (en)
JP3108710B2 (en) * 1997-12-26 2000-11-13 株式会社メタルアート Manufacturing method of the transmission gear
WO2014085389A1 (en) 2014-06-05 application
EP2925241A1 (en) 2015-10-07 application
EP2925241A4 (en) 2016-07-06 application
WO1998027876A1 (en) 1998-07-02 Surgical instrument
US20130018376A1 (en) 2013-01-17 Devices and Methods For the Preparation of Intervertebral Discs
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SCHMITZ, GREGORY P.;LEGUIDLEGUID, RONALD;WU, MING-TING;AND OTHERS;REEL/FRAME:033133/0390