Patent Document

CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 61/192,413, filed Sep. 18, 2008, the disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention generally relates to a control or switch arrangement for a medical instrument or tool, and specifically to an arrangement which automatically seals itself upon assembly and without the need for a sealing agent. 
     BACKGROUND OF THE INVENTION 
     Medical instruments or tools are utilized during surgery for various purposes. In this regard, cutting instruments, such as surgical saws, are utilized to shape and remove bone, for example, for the purpose of preparing a joint for receiving an implant, such as a hip implant. Other types of surgical tools may be used in what are generally termed endoscopic procedures. Endoscopy in the medical field allows internal features of the body of a patient to be viewed without the use of traditional, fully-invasive surgery. Endoscopic imaging systems incorporate an endoscope so as to enable a user to view a surgical site, and endoscopic tools enable non-invasive surgery at the site. Such tools may be shaver-type devices which mechanically cut bone and hard tissue, or radio-frequency (RF) probes which are used to remove tissue via ablation or coagulate tissue to minimize bleeding at the surgical site, to name a few. 
     In endoscopic surgery, the endoscope is placed in the body at the location at which it is necessary to perform a surgical procedure. Other surgical instruments, such the endoscopic tools mentioned above, are also placed in the body at the surgical site. The surgeon views the surgical site through the endoscope in order to manipulate the tool to perform the desired surgical procedure. Some endoscopes are usable along with a camera head, for the purpose of processing the image data received by the endoscope. The eyepiece of such an endoscope is typically coupled to the camera head, which camera head is connected to a camera control unit. 
     The development of endoscopes and their companion surgical tools has made it possible to perform minimally invasive surgery that eliminates the need to make a large incision in the patient to gain access to the surgical site. Instead, during endoscopic surgery, small openings, called portals, are formed. One advantage of performing endoscopic surgery is that since the portions of the body that are cut are reduced, the portions of the body that need to heal after the surgery are likewise reduced. Still another advantage of endoscopic surgery is that it exposes less of the interior tissue of the patient&#39;s body to the open environment. This minimal opening of the patient&#39;s body lessens the extent to which the patient&#39;s internal tissue and organs are open to infection. 
     Surgical instruments, such as surgical saws, shavers, RF devices, camera heads for use in conjunction with endoscopes and other surgical tools, typically incorporate some type of control arrangement located on the instrument which facilitates manual control of the instrument or tool by the surgeon. For example, a conventional RF probe typically includes a control or button arrangement to allow the user to select “CUT” to ablate tissue or “COAG” to coagulate tissue. Similarly, a shaver arrangement typically incorporates a handpiece to which a shaver probe is attached, wherein the handpiece includes a control arrangement with various buttons to control the direction, speed, etc. of the rotating shaver blade. Camera heads usable with endoscopes likewise incorporate control arrangements to allow the user to control various functions of the camera head, such as zoom, pan, white balance, picture, etc. 
     Due to the type of environment in which the above surgical instruments are utilized, it is necessary to seal internal electrical and mechanical components of the instruments from the external environment, which can have varying humidity levels, or fluids and/or other contaminants present which could harm the instruments and disrupt the functioning thereof. Control arrangements, such as switches, may be mounted in openings formed in the housings of the instruments, and such openings and control arrangements must be adequately sealed from the environment. One known method of sealing control arrangements of this type is to utilize a sealing agent, such as silicone, around the control or switch arrangement at the junction between the arrangement and the instrument housing. Such an arrangement is utilized on the commercially available FORMULA® shaver handpiece used in arthroscopy procedures, as sold by the Assignee hereof. Specifically, the control arrangement includes a keypad including one or more control buttons thereon, which keypad is then held in the housing opening by a cover plate. The cover plate is held in place by screws, and a sealing agent is applied to the juncture between the housing and the cover plate. While this method is effective for its intended purpose, same nonetheless requires additional components and assembly steps during assembly, which can be time-consuming and costly from a manufacturing perspective. 
     Other known methods include the use of switch components which are permanently press-fit or adhered to the instrument housing. This method, however, accordingly does not allow disassembly of the arrangement, which is sometimes desirable or necessary for maintenance or repair purposes. 
     In order to obviate or at least minimize the disadvantages of known sealing arrangements, the instant invention includes a control arrangement which cooperates with a housing of the instrument or tool to provide a seal therebetween upon assembly of the control arrangement to the tool housing. The control arrangement includes an actuator member or keypad having a button or buttons thereon associated with a control function of the instrument, a retaining clip configured for securing the control arrangement to the tool housing and a sealing member. The tool housing has a housing wall which defines an opening therein for receiving the control arrangement, and the housing wall includes a sealing surface adjacent the opening. The retaining clip is disposed within a portion of the housing opening defined outwardly of the actuating member, and is resiliently disposed in such opening portion to prevent dislodgement of the control arrangement from the tool housing. Further, the retaining clip, when engaged within the housing opening, causes sealing engagement of the sealing member with the sealing surface of the housing wall automatically upon assembly of the retaining clip to the housing. 
     This automatic sealing function of the control arrangement when assembled to the tool housing serves to fully seal the arrangement from the exterior environment of the housing, without the need for the application of a sealing agent, such as silicone or the like, to the junction between the control arrangement and the housing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of an endoscopic camera arrangement including an example of one type of scope assembly incorporating a sealed control arrangement pursuant to the invention; 
         FIG. 2  is an enlarged and fragmentary perspective view of the scope assembly of  FIG. 1 ; 
         FIG. 3  is an enlarged and fragmentary exploded perspective view of portions of the scope assembly of FIG.  1 , illustrating the various components of the control or switch arrangement; 
         FIG. 4  is an enlarged and fragmentary view of the camera head of the scope assembly; 
         FIG. 5  is an enlarged, fragmentary cross-sectional view of the housing of the camera head as seen generally along line  5 - 5  in  FIG. 3 ; 
         FIG. 6  is an enlarged, fragmentary cross-sectional view of the housing of the camera head as seen generally along line  6 - 6  in  FIG. 3  and rotated clockwise by about 90 degrees; 
         FIG. 7  is an enlarged cross-sectional view of the keypad of the control arrangement as seen generally along line  7 - 7  in  FIG. 3 ; 
         FIG. 8  is an enlarged plan view of the cover plate of the control arrangement; 
         FIG. 9  is an enlarged cross-sectional view of the cover plate as seen generally along line  9 - 9  in  FIG. 8 ; 
         FIG. 10  is an enlarged plan view of the retainer clip of the control arrangement; and 
         FIG. 11  is an enlarged, fragmentary cross-sectional view of the control arrangement as seen generally along line  11 - 11  in  FIG. 4 . 
     
    
    
     Certain terminology will be used in the following description for convenience in reference only, and will not be limiting. For example, the words “upwardly”, “downwardly”, “rightwardly” and “leftwardly” will refer to directions in the drawings to which reference is made. The words “inwardly” and “outwardly” will refer to directions toward and away from, respectively, the geometric center of the arrangement and designed parts thereof. The words “forwardly” and “distally” will refer to the direction toward the end of the arrangement which is closest to the patient, and the words “rearwardly” and “proximally” will refer to the direction away from the end of the arrangement which is furthest from the patient. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import. 
     DETAILED DESCRIPTION 
     For purposes of illustration,  FIG. 1  shows an endoscopic camera arrangement  10 , including a scope assembly  11  which may be utilized in endoscopic procedures, for example. The scope assembly  11  incorporates an endoscope or scope  12  which is coupled to a camera head  13  by a coupler  14  located at the distal end of camera head  13 . Camera head  13  incorporates well-known circuitry, such as a charge-coupled device (CCD) or a complementary metal oxide semi-conductor (CMOS), for acquiring color video image data of internal features of the body through one or more lenses within the scope  12 . Light is provided to the scope  12  by a light source  14 A via a light conduit  15 , such as a fiber-optic cable. The camera head  13  is coupled to a camera control unit (CCU)  17  by a transmission cable  18 . Operation of the camera arrangement  10  is controlled, in part, by CCU  17 . Cable  18  conveys video image data from the camera head  13  to the CCU  17  and conveys various control signals bi-directionally between the camera head  13  and the CCU  17 . In one embodiment, the image data output by the camera head  13  is digital, in which case cable  18  may be Firewire, a Universal Serial Bus (USB) or another type of high-speed digital interface. 
     A control or switch arrangement  20  ( FIG. 2 ) is provided on the camera head  13  and allows the user to manually control various functions of the camera arrangement  10 . These camera functions may also be controlled by voice commands using a voice control unit  23 , which control unit  23  is coupled to CCU  17 . Voice commands are input into a microphone  24  mounted on a headset  25  worn by the surgeon and coupled to the voice control unit  23 . A hand-held control device  26 , such as a tablet with a touch-screen user interface or a pendant, may be coupled to the voice control unit  23  as a further control interface. In the illustrated embodiment, a DVD recorder  27  and a printer  28  are also coupled to the CCU  17 . Additional devices, such as an image capture and archiving device, may be included in arrangement  10  and coupled to CCU  17 . Video image data acquired by camera head  13  and processed by CCU  17  is converted to images, which can be displayed on a monitor  29 , recorded by recorder  27 , and/or used to generate static images, hard copies of which images can be produced by printer  28 . 
     With reference to  FIGS. 3-6 , camera head  13  includes a housing  30  defined by a generally tubular housing wall  31  defining a hollow interior  32 . Interior  32  opens distally through an opening  33  which cooperates with coupler  14 , and sidewardly through a bore or opening  34  which extends completely through housing wall  31  and mounts therein control or switch arrangement  20 . Bore  34  is defined by an annular terminal edge portion of housing wall  31  having multiple stepped sections or portions as described below. 
     Housing wall  31  includes an annular flange  35  having an inner surface  36  oriented generally transverse to a longitudinal axis A of scope  11  (which axis A is generally parallel to a horizontal plane of bore  34 ), and generally parallel to a central axis B of bore  34  (which axis B is oriented transversely to axis A). Surface  36  defines a radially innermost portion  38  of bore  34  with respect to scope axis A, and in the illustrated embodiment portion  38  has the smallest diameter of all of the sections of bore  34 . Surface  36  is joined to a flat annular surface  39  which is generally parallel to scope axis A and generally perpendicular to bore axis B, which surface  39 , in turn, is joined to a further surface  40  of housing wall  31 . Surface  40  is essentially perpendicular to axis A and essentially parallel to axis B. Surfaces  39  and  40  are oriented transversely to one another, and in the illustrated embodiment together form a right angle. Further, surface  40  is located axially outwardly from surface  36  with respect to scope axis A, and is generally parallel to surface  36 , so as to define an intermediate portion  42  of bore  34  having a larger diameter than adjacent bore portion  38 . 
     An upper extent of surface  40  is joined to an annular sealing surface  44  which protrudes radially relative to scope axis A and is joined to a flat annular surface  45 . With respect to axis A, surface  45  is located radially inwardly from surface  44  and axially outwardly therefrom. Surface  45  is joined to a wall surface  48  which is generally parallel to surface  40  and is located axially outwardly (axis A) therefrom so as to define a further bore portion  50  of a larger diameter than adjacent bore portion  42 . Surface  48 , surface  45  and an outer surface of sealing surface or projection  44  together define an annular recess or notch  49  located immediately adjacent sealing projection  44 , and projecting radially inwardly relative thereto with respect to axis A. Surface  48  is joined to a flat annular surface  52  which adjoins an annular housing wall surface  53  located axially outwardly from wall surface  49  (axis A) and generally parallel thereto so as to define a further bore portion  60  of a greater diameter than adjacent bore portion  50 , but of a lesser radial dimension than bore portion  50  (axis A). 
     Bore portion  60  joins to an outermost bore portion  61  defined by an annular housing surface  63  located axially inwardly (axis A) from adjacent housing surface  53  such that housing wall  31  defines an outer flange  65  which overhangs bore portion  60  so as to form a retaining lip therearound. Outermost bore portion  61  is the radially outermost part of bore  34  (axis A). In the illustrated embodiment, flange  65  is annular. However, it will be appreciated that flange  65  may be embodied by a plurality of flanges or projections located about the periphery of bore  34 , or only a single flange of an adequate circumferential dimension may be provided along a portion of the outer periphery bore. 
     With reference to  FIGS. 5 and 6 , in the illustrated embodiment, flange  65  angles upwardly as same projects radially inwardly with respect to and towards axis B, and thus defines a slightly upwardly inclined inner surface  67  which is oriented at an angle in the range of about 15-20 degrees relative to axis A. 
     Turning now to control arrangement  20 , and with reference to  FIGS. 3 and 11 , same includes a membrane switch  70  having outer and inner members  71  and  72 . Outer member  71  mounts thereon a pair of switch contact pads  73  and  74  which are normally in the open position. Outer member  71  is generally planar and has an outer periphery sized so as to relatively snugly seat within bore portion  42  of housing bore  34  so that outer member  71  rests atop housing flange  35 , while inner member  72  projects into innermost bore portion  38 . Membrane switch  70  contains suitable circuitry electrically connected to the appropriate components within camera head  13  such that the appropriate control commands are carried out when contact pads  73  and  74  are actuated, as discussed further below. 
     Control arrangement  20  additionally includes an actuator or keypad  80 , as shown in  FIGS. 3 ,  7  and  11 . Keypad  80  has a base member  81  which surrounds and is joined to a pair of raised buttons  82  and  83  which project outwardly from base member  81 . Buttons  82  and  83  have respective upper or outer surfaces which include indicia thereon corresponding to various control functions of camera head  13 . In the illustrated embodiment, the buttons  82  and  83  respectively include the letters “P” and “W” thereon, which are representative of “picture” and “white balance” functions of camera head  13 . 
     Base member  81  of keypad  80  has an outer annular edge portion  85  which surrounds buttons  82  and  83 , and an inner web portion  86  disposed between buttons  82  and  83 . Edge portion  85  and web portion  86  are generally coplanar with one another, and in the illustrated embodiment are integrally formed as one-piece with buttons  82  and  83 . Web portion  86  includes a lower or inner generally flat surface  87 , and outer edge portion  85  includes a lower or inner surface  89  coplanar with surface  87 . Outer edge portion  85  defines an annular lip  88  which projects downwardly or inwardly from surface  89 . 
     Buttons  82  and  83  each have respective projections  90  and  91  which are cantilevered downwardly or inwardly and define respective lower or inner surfaces  92  and  93  which are generally planar and coplanar with one another. In the illustrated embodiment, keypad  80  is formed as a one-piece component constructed of an elastomeric and resilient material. 
     With reference to  FIG. 11 , keypad  80  is located within bore portion  50  so that lip  88  of base  81  engages within notch  49  and against sealing projection  44  and so that lower surface  89  of base edge portion  85  and lower surface  87  of web  86  seat on the upper surface of membrane switch  70 . Further, the lower surfaces  92  and  93  of actuating projections  90  and  91  of keypad  80  are spaced slightly upwardly from the respective contact pads  73  and  74  of membrane switch  70 . As shown in  FIG. 11 , when keypad  80  is assembled to housing  31  atop membrane switch  70 , actuating projections  90  and  91  are aligned with contact pads  73  and  74 . 
     Control arrangement  20  additionally includes a cover plate  100  as shown in  FIGS. 3 and 8 . Cover plate  100  is shaped to cooperate with keypad  80 , and includes a planar base wall  101  which defines therein openings  102  and  103  which extend completely through base wall  101  and are shaped to correspond with the outer peripheries of buttons  82  and  83 . Buttons  82  and  83  extend upwardly or outwardly through the respective openings  102  and  103  in the assembled condition of control arrangement  20 . As shown in  FIG. 11 , cover plate  100  seats atop base  81  of keypad  80  within bore portion  50 , with buttons  82  and  83  of keypad  80  located within the respective openings  102  and  103 . 
     With reference to  FIGS. 3 and 10 , control arrangement  20  additionally includes a retainer clip  110  defined by an elongated body  111  generally having an elliptical shape. Clip body  111  is of a split-ring construction, and thus has a pair of terminal or free ends  112  which are spaced sidewardly from one another to allow compression of clip  110 . As shown in  FIG. 10 , the free ends  112  have chamfers  113  which assist in removing clip  110  from housing  30 . Additionally, at the side of clip  110  diametrically opposite from ends  112 , body  111  projects inwardly so as to define a recess  114  which aids in installation of clip  110  by allowing easier compression thereof. 
     Referring to  FIG. 11 , with membrane switch  70 , keypad  80  and cover plate  100  assembled within bore  34  of housing  31 , these components of control arrangement  20  are secured within housing  30  via retainer clip  110 . Specifically, according to one assembly method, retainer clip  110  is compressed by applying pressure to the opposite sides of body  111  located between ends  112  and recess  114 , so that clip  110  can be inserted into and pass through outermost bore portion  61  over flange  65 . Once clip  110  has cleared surface  63  of flange  65  which defines bore portion  61 , the pressure on clip  110  is removed so that the clip  110  resiliently returns to its normal or at rest configuration (as shown in  FIG. 10 ) and moves into bore portion  60  atop cover plate  100 . In this regard, the angled surface  67  of flange  65  serves to guide the clip  110  downwardly during insertion or installation so that same seats within bore portion  60  and is brought into engagement with the cover plate  100 . With clip  110  in place within bore  34  of housing  31 , clip  110  prevents dislodgement of the underlying components of the control arrangement  20 , and also compresses keypad  80  and maintains lip  88  of keypad  80  in notch  39  and in contact with surfaces  48 ,  45  and  44  of housing  31  so as to effectively create a fluid-tight seal between the external environment and the components internal to housing  31 , including membrane switch  70  and the electronic circuitry and other components located within housing  30  of camera head  13 . In the illustrated embodiment, the dimensions of flange  88  of keypad  80  are somewhat larger than the dimensions of housing notch  39 , such that when keypad  80  is compressed against housing  30  by clip  110  a fluid-tight seal is achieved. Further, the upward tilt of flange  65  of housing wall  31  at surface  67  allows easier insertion of clip  110  into bore  34  of housing  30 , and also serves to adjust the depth of the clip  110  downwardly within bore portion  60  and accommodate for varying tolerances of the components of control arrangement  20 . 
     According to another assembly method, the clip  110  can be angled downwardly and one edge of clip  110  can be inserted directly into bore portion  60 . The opposite edge of clip  110  is then pushed downwardly past flange  65  and into bore portion  60 . 
     If desirable or necessary, the control arrangement  20  can be removed from the housing wall  31 . Specifically, as shown in  FIG. 4 , the clip  110  is removed from the housing  30  by inserting a tool behind one or both chamfers  113  of clip  110  and pushing the free ends  112  of clip  110  towards clip recess  114 . This action on clip  110  will cause same to disengage from bore portion  60 , and allow removal of cover plate  100 , keypad  80  and membrane switch  70 . 
     The control or switch arrangement  20  according to the invention as described above self-seals upon assembly of the retainer clip  110  into housing  31 , and thus avoids the need for application of a sealing agent, such as silicone, around or within bore  34 , which is time-consuming and costly from an assembly perspective. Additionally, the arrangement according to the invention allows disassembly of the control arrangement for purposes of repair or inspection. 
     It will be appreciated that the scope assembly  11  is shown herein for illustrative purposes only, and various types of surgical tools or instruments other than such scope assembly may incorporate the tool housing structure and control arrangement according to the invention. Some of these types of medical instruments are described above, such as surgical saws, shavers and RF probes. Other types of medical and surgical instruments may utilize the structure of the invention, and thus this invention is not to be construed as limited for use solely in a scope assembly or in the other surgical instruments described herein. 
     Although a particular preferred embodiment of the invention is disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangements of parts, lie within the scope of the present invention.

Technology Category: a