Abstract:
Disclosed is a coupling structure of surgical instrument. The coupling structure for a surgical instrument comprises a housing and a plurality of disc shaped driving wheels disposed in the housing, wherein the driving wheels are stacked along a driving axis that passes through the driving wheels, and are supplied with driving power from a plurality of actuators that are disposed to correspond respectively to the plurality of driving wheels, and provides a light compact surgical robot by disposing driving wheels in a piling arrangement, which also allows an used instrument to be automatically replaced with a new one.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is the National Phase of PCT/KR2008/005874 filed on Oct. 7, 2008, which claims priority under 35 U.S.C. 119(a) to Patent Application No. 10-2008-0013970 filed in the Republic of Korea on Feb. 15, 2008, all of which are hereby expressly incorporated by reference into the present application. 
     
    
     BACKGROUND 
       [0002]    The present invention relates to a coupling structure of a surgical instrument. 
         [0003]    Surgery refers to a medical specialty that uses operative manual and instrumental techniques on the tissues of a patient to treat a pathological condition. Surgical robots have been proposed as an alternative for performing an excision surgery, which needs cutting tissues to treat or remove the organ within the body, to reduce blood loss, pain and improve precision. 
         [0004]    The surgical robot consists of a master robot generating and transmitting signals according to a manipulation of a surgeon and a slave robot applying the manipulation directly to the patient according to the signals from the master robot. The master robot may be integrated with the slave robot or may be separated from the slave robot. 
         [0005]    The slave robot comprises robotic arms for surgical manipulation, and at a fore end of the robot arm is formed an instrument. The existing instrument  54  comprises, as shown in  FIG. 1 , a housing  108 , a shaft  102  extending from the housing  108 , and a pincer shaped manipulation part  112  formed at an end of the shaft  102  and inserted into a surgical site. An interface part  110  is formed at a bottom side of the housing  108 . 
         [0006]    As shown in  FIG. 2 , a plurality of wheel shape driving elements  118  are combined at the bottom side of the existing instrument  54 . The driving elements  118  are wound with wires connected with the manipulation part  112 , so that tension on the wires generated by the revolution of the driving elements  118  causes the manipulation part  112  to operate. 
         [0007]    In order to mount the instrument  54  on the robotic arm, an adaptor  128 , as shown in  FIG. 3 , is combined with the fore-end of the robotic arm. The adaptor  128  is formed with a guide wing and actuators. The interface part  110  of the housing  108  is coupled with the adaptor  128  through the guide wing and the actuator has a shape corresponding with the driving element to provide revolution power to the driving element. 
         [0008]    As described above, the existing instrument  54  has a coupling structure in which the instrument  54  is combined with the robotic arm through the adaptor  128 , and performs surgery by operating the manipulation part  112  by revolving the driving element  118  through the actuator formed in the adaptor  128 . 
         [0009]    However, in such a coupling structure, there is a limit to reducing the size of the housing because the driving elements should be disposed on the bottom surface of the housing. As seen in  FIG. 2 , when two arrays of the driving elements are disposed, the bottom plane should be twice as wide as the diameter of the driving elements. 
         [0010]    This limit in reducing the size of the instrument becomes an obstacle to miniaturizing the surgical robot and also to applying a technology for automatically replacing the disposable instrument. 
       SUMMARY 
       [0011]    The present invention aims to provide a coupling structure of a surgical instrument that can miniaturize a surgical robot by minimizing the size of the surgical instrument, and that can serve as a technology for enabling automatic replacement of the disposable instrument. 
         [0012]    According to one aspect of the present invention, a coupling structure for a surgical instrument is provided, the coupling structure comprising a housing and a plurality of disc shaped driving wheels disposed in the housing, wherein the driving wheels are stacked along a driving axis that passes through the driving wheels, and are supplied with driving power from a plurality of actuators that are disposed to correspond respectively to the plurality of driving wheels. 
         [0013]    The coupling structure may further comprise a plurality of wires that are respectively wound around the driving wheels and deliver driving power to a manipulation part formed on a fore-end of the surgical instrument. 
         [0014]    The driving axis may be perpendicular to a surface the driving wheel. 
         [0015]    The driving axis may pass through a center of the driving wheel. 
         [0016]    A thickness of the housing may amount approximately to a sum of thickness of the plurality of driving wheels. 
         [0017]    The plurality of actuators may be stacked along an axis, and each actuator may comprise a wheel that is engaged with a corresponding driving wheel by a rolling contact. 
         [0018]    A circumferential surface of the driving wheel may comprise rubber material on which a plurality of protrusions are formed. 
         [0019]    A surface of the driving wheel may be exposed to a outer surface of the housing, and each actuator may comprise a wheel contacting a corresponding disc of the driving wheel. 
         [0020]    A surface of the driving wheel facing the actuator may comprise rubber material on which a plurality of protrusions are formed. 
         [0021]    A gear may be formed on the surface of the driving wheel facing the actuator, and the actuator may comprise a driving gear that forms a gear combination with the driving wheel. 
         [0022]    The coupling structure may further comprise a plurality of sub wheels that are disposed in the housing to correspond respectively to the plurality of driving wheels and respectively form a pulley combination with the driving wheels, wherein each actuator comprises a slider that applies a tension to the pulley by a slide movement. 
         [0023]    A gear may be formed on a circumferential surface of the driving wheel and each actuator may comprise a driving gear forming a gear combination with the driving wheel. 
         [0024]    The coupling structure may further comprise a plurality of sub wheels that are exposed on a side of the housing to correspond respectively to the plurality of driving wheels, and form a gear combination or a pulley combination with the driving wheels, wherein each actuator comprises a driver applying torque to corresponding sub wheel. 
         [0025]    On an exposed area of the sub wheel may be formed a groove, and on an end of the driver may be formed a protrusion having a shape corresponding to the groove. 
         [0026]    Additional aspects, features, and advantages will be elucidated from the following drawings, claims, and specification. 
         [0027]    This invention provides a light compact surgical robot by disposing driving wheels in a piling arrangement, which also allows an used instrument to be automatically replaced with a new one. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]      FIGS. 1 through 3  illustrate a surgical instrument according to prior art. 
           [0029]      FIG. 4  is a perspective view illustrating a coupling structure of a surgical instrument according to an embodiment of the present invention. 
           [0030]      FIG. 5  is a side view of a coupling structure of a surgical instrument according to an embodiment of the present invention. 
           [0031]      FIG. 6  is a side view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. 
           [0032]      FIG. 7  is a side view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. 
           [0033]      FIG. 8  is a perspective view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. 
           [0034]      FIG. 9  is a perspective view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0035]    Although a few embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents. Also, specific descriptions on related prior art will be omitted in order to concentrate on the gist of the present invention. 
         [0036]    The terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. 
         [0037]    The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto and is limited only by the claims. Where an indefinite or definite article is used when referring to a singular noun e.g. “a” or “an”, “the”, this includes a plural of that noun unless something else is specifically stated. 
         [0038]    It is to be noted that the term “comprising”, used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. 
         [0039]    Hereinafter, same reference numerals refer to the same or similar parts throughout the drawings and repetitive descriptions about the same element are omitted. 
         [0040]      FIG. 4  illustrates in a perspective view a coupling structure of a surgical instrument according to an embodiment of the present invention. In  FIG. 4  are shown an instrument  1 , a housing  10 , a driving wheel  20 , a driving axis  22 , a wire  24 , a manipulation part  26 , and an actuator  40 . 
         [0041]    A feature of this embodiment is that a width of the housing  10  of the instrument  1  can be minimized by stacking the driving wheels  20  of the instrument  1  along an axis direction. 
         [0042]    The instrument  1  comprises the housing  10 , a shaft extending from the housing  10 , and the manipulation part  26  combined with an end of the shaft. In the housing  10 , the driving wheels  20  are disposed not in a planar arrangement but in a stacked arrangement. 
         [0043]    A width of the housing  10  can be narrowed by stacking the disc shaped driving wheels  20  in the direction of an axis penetrating the driving wheels  20 , instead of disposing the driving wheels  20  in a planar arrangement. For example, the prior instrument in  FIG. 2  should be at least twice as wide as the diameter of the driving wheel However, when the driving wheels  20  are stacked as shown in  FIG. 4 , the thickness of the housing  10  corresponds to the height of the stack of the driving wheels  20 , and the width of the housing  10  can be narrowed to correspond to the diameter of the driving wheels  20 . 
         [0044]    As described above, the present invention can contribute to reducing the size and weight of a surgical robot by reducing the size of the housing  10  of the surgical instrument  1 . In particular, a plurality of instruments  1  can be supplied sequentially in a cartridge type, thereby facilitating the introduction of an automatic replacement system for used instruments  1 . 
         [0045]    The disc type driving wheel  20  of the instrument  1  revolves around the driving axis  22 , which perpendicularly penetrates a center of the discs. Accordingly, the driving wheels  20  may be stacked in a direction of the driving axis  22 . The width of the housing  10  can be minimized when stacking the driving wheels  20  in the direction of the axis  20 , and the thickness of the housing  10  can be minimized when the driving axis  22  is perpendicular to the driving wheels  20 . 
         [0046]    However, the axis  22  does not necessarily have to be perpendicular to the wheels  20 , and the wheels  20  may be disposed, for example, in a zigzag arrangement. 
         [0047]    The instrument  1  in which the driving wheels  20  are repeatedly arrayed as shown in  FIG. 4  is disposed in a predetermined position of the robot arm. Similar to an existing instrument, the housing  10  of the present embodiment may have an interface part on its bottom side, and a guide wing may be formed on a corresponding position of the robot arm that allows the interface part to be fixed. Details on the interface part and the guide wing will not be described. 
         [0048]    When disposed in the predetermined position of the robot arm, the instrument  1  is provided with driving power from the robot arm. Each wheel  20  is wound with the wire  24 , which is connected through the shaft with the manipulation part  26 . Accordingly, the driving wheels  20  revolve due to the driving power from the robot arm, generating tension on the wire  24 , which causes units of the manipulation part  26  to operate. 
         [0049]    Hereinafter, a unit in the robot arm delivering driving power to the instrument  1  will be referred to as an actuator. The actuator  40  may comprise a wheel, a slider, a gear, and the like as a means for delivering driving power to each driving wheel  20 . The actuator  40  will be described in detail with reference to  FIGS. 5 through 7 . 
         [0050]      FIG. 5  is a side view showing a coupling structure of a surgical instrument according to an embodiment of the present invention. In  FIG. 5  are illustrated an instrument  1 , a housing  10 , a driving wheel  20 , a wire  24 , and an actuator  40 . 
         [0051]    A feature of this embodiment is that the actuator  40  comprises a plurality of wheels, each wheel being engaged with a corresponding driving wheel  20  by rolling contact. The wheels contact the driving wheels  20  such that when the wheel in the actuator  40  rotates, the engaged driving wheel  20  also rotates in synchronization therewith. 
         [0052]    In this way, driving power can be provided through the actuator  40 , and the accuracy of the manipulation can be adjusted by altering the ratio of the radius of the driving wheel  20  to the radius of the wheel of the actuator  40 . More specifically, when the wheel of the actuator  40  is larger than the driving wheel  20 , a small amount of rotation of the wheel of the actuator  40  allows the driving wheel a relatively larger amount of rotation. Conversely, when the driving wheel  20  is larger than the wheel of the actuator  40 , the driving wheel performs a smaller amount of rotation than the wheel of the actuator  40 . Therefore, the radius ratio will be determined depending on a desired accuracy of an operation. 
         [0053]    It is recommendable that the friction coefficient of a circumferential surface of the wheel of the actuator  40  and/or of the driving wheel  20  be high in order to enhance the efficiency in delivering the driving power. For example, a plurality of protrusions (H may be formed on the circumferential surface, or the circumferential surface may be made of a material having a high frictional coefficient such as rubber, so that the rotational power of the wheel of the actuator  40  can be delivered to the driving wheel efficiently. 
         [0054]      FIG. 6  is a perspective view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. In  FIG. 6  are shown an instrument  1 , a housing  10 , a driving wheel  20 , a wire  24 , a sub wheel  30   a , a pulley  32 , an actuator  40   a , and a slider  42 . 
         [0055]    A feature of this embodiment is that the sub wheel  30   a  is additionally disposed in the housing  10  to be connected with the driving wheel  20  by the pulley  32 , and a plurality of sliders  42  are disposed in the actuator  40   a  to apply tension to the pulley  32 . 
         [0056]    As shown in  FIG. 6 , when the pulley  32  is pulled toward the driving wheel  20  or the sub wheel  30   a , the driving wheel  20  accordingly rotates clockwise or counter-clockwise. 
         [0057]    By comprising the slider  42  as a means for applying tension to the pulley  32 , the actuator  40   a  provides driving power to the instrument  1  as in the preceding embodiment of  FIG. 5 . The slider  42  corresponding to the driving wheel  20  moves in a reciprocating motion, pulling the pulley  32  toward the driving wheel  20  or the sub wheel  30   a , thereby rotating the driving wheel  20  in synchronization therewith. 
         [0058]    The manipulation part  26  of the instrument  1  moves within a predetermined range, which means that the rotation of the driving wheel  20  should be restricted within a predetermined range. In the preceding embodiment in  FIG. 5 , the rotation of the wheel of the actuator  40   a  may be restricted in order to restrict the rotation of the driving wheel  20 , and to this end, brake elements may be formed on certain positions of the wheel. 
         [0059]    In the present embodiment, a moving guide of the slider  42  may be designed to have a length that allows the slider  42  to move within a restricted range, thereby putting a limit on the movement of the manipulation part  26  of the instrument  1 . 
         [0060]    It is recommendable that the friction coefficient between the slider  42  and the pulley  32  be high, in a similar manner to the preceding embodiment in  FIG. 5 . A groove (         ) may be formed on the slider  42  so that the pulley  32  can be inserted in the slider  42 , and the surface of the slider  42  and/or pulley  32  may be made of a material with a high frictional coefficient such as rubber, so that the movement of the slider  42  can be converted into the rotation of the driving wheel  20  efficiently. 
         [0061]      FIG. 7  is a side view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. In  FIG. 7  are shown an instrument  1 , a housing  10 , a driving wheel  20 , a wire  24 , an actuator  40   b , and a driving gear  44 . 
         [0062]    A feature of this embodiment is that gears are formed around the circumference of the driving wheels  20 , and the actuator  40   b  comprises the driving gears  44 , each forming a gear-combination with a counterpart driving wheel  20 , so that the driving wheel  20  rotates in synchronization with the driving gear  44 . 
         [0063]    The gear combination for the driving gear  44  and the driving wheel  20  may be a spur gear, as shown in  FIG. 7 , a helical gear, a worm gear, a rack and pinion, or the like. 
         [0064]    With such a configuration, the actuator  40   b  can deliver driving power, and a gear ratio between the driving wheel  20  and the driving gear  44  may be altered to adjust the accuracy of the instrument  1 . 
         [0065]    Unlike the preceding embodiments in  FIG. 5  and  FIG. 6 , the role of the frictional coefficient is relatively unimportant since the gear is efficient in delivering driving power. 
         [0066]    As seen in the above, the present invention provides a surgical instrument in which the width or the size of a housing may be reduced by altering the size of a driving wheel, optimizing the arrangement of driving wheels, and employing sub wheels. 
         [0067]      FIG. 8  is a perspective view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. In  FIG. 8  are shown an instrument  1 , a housing  10 , driving wheels  20 , a manipulation part  26 , and an actuator  40   c.    
         [0068]    This embodiment introduces an example of an arrangement for the driving wheels  20  in which a plurality of driving wheels  20  are arranged in pairs and some of the pairs are disposed in a fore part of the housing  10  and the rest of the pairs are disposed in a rear part, while all of the driving wheels are stacked along the driving axis in  FIG. 4 . 
         [0069]    The actuator  40   c  may have a similar configuration to that in  FIG. 4 , or in the case that the disc of the driving wheel is partially or entirely exposed at the outside of the housing  10  as shown in  FIG. 8 , the actuator  40   c  may have a plurality of wheels clutched with the driving wheels  20  from the outer side of the housing  10 . In other words, the actuator  40   c  has wheels corresponding to the driving wheels  20 , thereby rotating the driving wheels  20  in synchronization therewith. 
         [0070]    In order for an efficient combination of the wheels of the actuator  40   c  with the driving wheels  20 , the surfaces of the discs of the driving wheels  20  and/or the surfaces of the wheels of the actuator  40   c  facing the driving wheels  20  may be made of rubber, and protrusions may also be formed on the surfaces. Alternatively, a gear may be formed on the disc of each of the driving wheels  20 , and each wheel of the actuator  40   c  may be a driving gear (not shown) that forms a gear combination with the gear of the driving wheel  20 . 
         [0071]    The thickness of the housing  10  may be narrower than that in the embodiment shown in  FIG. 4  when the driving wheels  20  are aligned in pairs in a lengthwise direction of the housing  10 . 
         [0072]      FIG. 9  is a perspective view illustrating a coupling structure of a surgical instrument according to another embodiment of the present invention. In  FIG. 9  are shown an instrument  1 , a housing  10 , sub wheels  30   b , a manipulation part  26 , an actuator  40   d , and a driver  46 . 
         [0073]    Reducing the size of the housing  10  of the instrument  1  as shown in  FIG. 8  may facilitate the implementation of an automatic replacement system that supplies a plurality of instruments  1  sequentially in a cartridge type. 
         [0074]    In order to apply a replacement system to the instrument  1 , one end of each of the sub wheels  30   b  may be exposed as shown in  FIG. 9  at a rear side of the housing  10 . The above description on the driving wheels is equally valid for this embodiment. 
         [0075]    In the embodiment shown in  FIG. 9 , the driving wheels in the housing  10  are combined with the sub wheels  30   b  through gears, wires, pulleys, or the like, and one end of each of the sub wheels  30   b  is exposed at the rear side of the housing  10 . A worm gear combination, for example, may be employed for the combination of the sub wheel  30   b  and the driving wheel in order to expose one end of the sub wheel  30   b  at an outer surface of the housing  10 . 
         [0076]    In the exposed surface of the a sub wheel  30   b , there may be formed a slot having a shape of −, +, or the like, as on the head of a screw, and a driver  46  having a tip that is shaped to correspond to the slot may be engaged with the sub wheel  30   b , so that driving power can be supplied to the instrument  1 . 
         [0077]    To be more specific, the driver  46  rotates, causing the sub wheel  30   b  to rotate, and in synchronization therewith the driving wheel (not shown) that is combined with the sub wheel  30   b  also rotates, eventually allowing the manipulation part  26  to operate. 
         [0078]    Although the present invention is described by referring to certain preferred embodiments, it will be appreciated by those skilled in the art that changes may be made without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.