Abstract:
A rotatable endoscope coupler which enables an endoscope to be rotatably attached to a camera and selectively locked in place. The coupler enables single handed rotation of the scope while the camera remains in a fixed orientation. A plurality of ceramic ball bearings riding in a stainless steel race enable the coupler to be repeatedly autoclaved. A locking mechanism allows the scope and camera to be fixed from relative rotation.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to endoscope couplers for optically and mechanically coupling an endoscope to a video camera. More particularly, the invention relates to endoscope couplers which enable relative rotation of the endoscope and camera about the endoscope axis. 
   2. Description of the Prior Art 
   Endoscopes have become widely utilized in surgery for viewing body cavities and organs to permit performance of diagnostic and surgical procedures internally without the need for invasive surgical procedures. An endoscope is typically inserted through a small incision or portal or natural body passage to provide access to the body cavity. A lens at a distal end of the endoscope is positioned to receive light reflected from a site to be observed, and images of the site can be viewed remotely to conduct diagnostic examinations and to perform closed, or endoscopic surgery. As used herein, the term endoscope refers generically to viewing devices for remotely observing otherwise inaccessible body cavities with minimal trauma and intrusion, including but not limited to arthroscopes, colonoscopes, bronchoscopes, hysteroscopes, cystoscopes, sigmoido-scopes, laparoscopes and ureterscopes, etc. 
   Endoscopes are sometimes supplied with an eyepiece at the proximal end thereof, and relay lenses in the endoscope typically produce an image for direct viewing through the eyepiece. However, adaptation of video camera technology to endoscopy imaging has enabled the output image of an endoscope to be viewed on a video monitor. Specifically, a video camera is electronically coupled to the video monitor and optically and mechanically coupled with the proximal end of the endoscope. Indirect or video monitor viewing of endoscopic images provides numerous benefits over direct viewing through an eyepiece, including: protection of a direct viewer&#39;s vision from high intensity illumination passed through the endoscope and reflecting off bodily tissue; enhancement of operator comfort and freedom of movement; increased endoscope utility and efficiency; reduction in the time required to conduct many endoscopic procedures; simultaneous viewing of endoscopic images by more than one person; and recordation and real time transmission of images of surgical procedures. 
   An endoscope coupler is required to couple the proximal end of the endoscope to the video camera and may be made as a separate device or in combination with either the endoscope or the video camera or both. Illustrative endoscope couplers are shown in U.S. Pat. No. 4,569,333 (Bel et al.); U.S. Pat. No. 4,611,888 (Prenovitz et al.); U.S. Pat. No. 4,740,058 (Hori et al.); U.S. Pat. No. 4,781,448 (Chatenever et al.); U.S. Pat. No. 4,807,594 (Chatenever); U.S. Pat. No. 4,844,071 (Chen et al.); U.S. Pat. No. 4,969,450 (Chinnock et al.); U.S. Pat. No. 5,056,902 (Chinnock et al.) and U.S. Pat. No. 5,359,992 (Hori et al.). Endoscope couplers sometimes include a cylindrical body which may be closed at opposing ends by end windows and contain a lens holder carrying one or more lenses longitudinally movable within the body to optically adjust an image from the endoscope onto a focal plane of the camera. The optical adjustments most commonly used may be a focus and/or zoom adjustment. Sometimes, endoscope couplers operate with the eyepiece of an endoscope and other times the eyepiece is replaced with an optical arrangement which must be viewed through the camera and monitor (that is, no eyepiece is available). 
   In addition to enabling optical adjustments, in certain applications such as the urology field, it is often necessary to maintain the camera in a fixed position while rotating the endoscope about its axis in order to view the surgical site. Therefore, rotatable endoscopic couplers have been developed to enable this rotation of the scope relative to the camera. Such couplers may not include any optical components although they serve to properly position the proximal end of the scope relative to the distal end of the camera so the image planes are properly spaced along their common axis. Known rotatable endoscopic couplers generally include a distal ring, which may be fixedly attached to the proximal end of the endoscope, a proximal ring, which may be fixedly attached to a camera, and a rotatable interface between the two rings. The rotatable interface often includes a plain bearing structure (not ball bearings) and a selectively actuatable lock (such as a lever with a pin or cam) to selectively prevent rotation. 
   Additionally, it is advantageous for the surgeon to use only one hand to manipulate the scope or the camera thereby leaving the other hand free to operate various instruments during surgical procedures. Therefore, rotatable couplers must be easy to operate. 
   Aforementioned U.S. Pat. No. 4,969,450 (Chinnock et al.) discloses a rotatable coupler for a video arthroscope which can be held and controlled with one hand. The rotatability is achieved by closely fitting cylindrical members including bores and counterbores which are rotatable about their common axes and sealed with several O-rings. 
   Another example of a rotatable coupler is shown in U.S. Pat. No. 4,611,888 (Prenovitz et al.). The Prenovitz coupler consists of two sections rotatable with respect to one another, the front section being non-rotatably mounted to the proximal end of an arthroscope and the rear section being non-rotatably mounted to the distal end of a video camera. The image produced by the scope is rotatable relative to the camera by simply rotating the front section relative to the rear section. 
   In order to maintain sterile surgical conditions, all imaging components, including endoscope couplers, whether rotatable or not, must be sterilized before and after each use. Steam autoclaving has long been the best accepted method of sterilization and is used for all instruments that can withstand the necessary high temperature and pressure. Instruments that will not survive the steam autoclave process, such as video cameras and prior art endoscopic couplers are treated by less effective or less efficient means such as immersion in sterilization liquid or gas sterilization. However, there is no known conventional rotatable endoscopic coupler which can withstand repeated steam or other sterilization and all known rotatable endoscopic couplers are adversely affected by such. 
   While known prior art couplers are available to enable the rotation of the endoscopic image relative to the camera, all known rotatable couplers utilize bearing surfaces, which are rotatable relative to each other, and locking mechanisms in the form of cams and pins to frictionally engage the rotatable elements to lock them together when the desired angular orientation is achieved. Over time, these known rotatable coupler designs become more and more difficult to operate because of the build up of residue caused by improper cleaning as well as the deterioration of the cooperating parts caused by their exposure to the harsh environments of autoclaves. This deterioration eventually leads to the inability to easily operate the rotatable coupler with one hand and eventually leads to the inability to rotate the coupler at all. These prior art couplers must then be totally rebuilt or replaced. 
   An improved rotatable coupler design is necessary in order to enable the autoclavability of rotatable endoscopic couplers and improve their performance over an extended period of time. 
   It is, therefore, an object of this invention to produce a rotatable endoscope coupler for joining an endoscope to a camera. 
   It is also an object of this invention to provide a rotatable endoscope coupler capable of being repeatedly subjected to an autoclave without significant deterioration of performance. 
   It is still another object of this invention to produce a rotatable endoscope coupler incorporating ball bearings which are adapted to withstand the autoclave environment. 
   It is still another object of this invention to produce a rotatable endoscope coupler capable of being easily disassembled for repair. 
   It is also an object of the present invention to provide an endoscope coupler that may be quickly and easily inserted between an endoscope and a video camera or may be formed as an integral part of either the endoscope or the video camera or both. 
   SUMMARY OF THE INVENTION 
   These and other objects are accomplished by the preferred embodiment disclosed herein which is a rotatable coupler for coupling a camera to an optical assembly, preferably an endoscopic optical assembly. The coupler comprises a proximal camera attachment means for fixedly securing the coupler to a camera, a distal optical assembly attachment means for fixedly securing the coupler to an optical assembly and a selectively rotatable coupling means interposed between the camera attachment means and the optical assembly attachment means. In one embodiment, the rotatable coupling means comprises a first annular member which is fixedly connected to the optical assembly attachment means and a second annular member is fixedly secured to the camera attachment means. An annular ball bearing means is interposed between the first and second annular members to permit relative rotation therebetween. The first annular member has a plurality of radially inwardly directed slots and a locking means attached to the second annular member annular member is adapted to selectively engage the slots to lock the first annular member to the second annular member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevational view of an endoscope, a camera and a rotatable coupler constructed in accordance with the principles of this invention. 
       FIG. 2  is a top plan view of a portion of  FIG. 1 . 
       FIG. 3  is a cross-sectional perspective view taken generally along the line  3 - 3  of  FIG. 2 . 
       FIG. 4  is an exploded view of a portion of  FIG. 3 . 
       FIG. 5  is a cross-sectional view of  FIG. 2  taken along the line  5 - 5 . 
       FIG. 6  is a front elevational view of the first annular ring (element  30 ) shown in  FIG. 4 . 
       FIG. 7  is a side elevational view of  FIG. 6 . 
       FIG. 8  is a rear elevational view of  FIG. 6 . 
       FIG. 9  is a cross-sectional view of  FIG. 6  taken along the line  9 - 9 . 
       FIG. 10  is a cross-sectional view of the second annular ring (element  32 ) shown in  FIG. 4 . 
       FIG. 11  is an enlarged view of a portion of  FIG. 10 . 
       FIG. 12  is a front elevational view of the locking tab element  92  shown in  FIG. 4 . 
       FIG. 13  is a cross-sectional view of  FIG. 12  taken along the line  13 - 13 . 
       FIG. 14  is a rear elevational view of  FIG. 12 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 and 2  show an endoscope  10  releasably connected to a camera head  12  via an intermediate rotatable coupler assembly  14  constructed in accordance with the principles of this invention. 
   Coupler assembly  14  comprises a distal cylindrical “grabber” means  20 , which is releasably attachable to the eyepiece of scope  10 , and a proximal camera mount means  22  which, in the preferred embodiment is fixedly attached to camera  12 . Grabber means  20  is selectively rotatable relative to camera mount means  22  by virtue of interface or bearing means  24  interposed therebetween, as best seen in  FIG. 3 . The freely rotatable grabber means enables a user to permit the camera head  12  (and, therefore, the monitor view) to remain fixed in selected orientation (e.g. upright), while rotating the scope about axis  46 . Either the scope or the camera may be rotated about the axis with the fingers of the hand holding the camera head. For applications such as urology, for example, the surgeon need only grasp the scope thereby allowing the camera to orient itself vertically by virtue of the weight of power cord  16 . Simply rotation of the scope about its axis will not affect the camera orientation. As will be explained below, for procedures requiring the scope and camera to be non-rotatable relative to each other, a locking feature is provided. 
   While the drawings are shown with an embodiment of the invention adapted to be used with an endoscope having an eyepiece, it will be understood that the invention could be adapted for use with any type of scope. The grabber means  20  may be replaced with an interface adapted to be affixed (permanently or removably) to the particular configuration of the proximal end of the scope to be coupled to the camera. Similarly, the rotatable coupler could be irremovably attached to the scope, or irremovably or removably attached to the camera, or removably or irremovably attachable to both. 
   As best seen in  FIGS. 3 through 5 , bearing means  24  comprises a distal, first annular ring  30  fixedly attached to grabber means  20 , a proximally situated second annular ring  32  and a laterally situated, third annular ring  34 . Annular rings  30 ,  32 ,  34  have cooperating surfaces  36 ,  38  and  40 , respectively, which, when assembled, serve as a race  42  for a plurality of balls  44  circumferentially situated about the axis  46  of the coupler assembly  14 . The assembly of the component parts of bearing means  24  may be understood by reference to the exploded view shown in  FIG. 4 . 
   It is noted that, in the preferred embodiment, race  42  is defined by three cooperating and threadably assembled stainless steel surfaces  36 ,  38  and  40  for ease of assembly and servicing. It will be understood that race  42  could be formed by more or fewer cooperating surfaces depending upon the design of the coupler, and could be assembled by means other than threads on rings  32  and  34 . In the preferred embodiment there are thirty five balls  44 , each made of ceramic and having a diameter of 0.125 inches. The ceramic material should be selected to withstand repeated sterilization cycles in an autoclave. However, should additional cleaning be required or should repairs or replacements be necessary, the rings  30 ,  32  and  34  may be easily disassembled. In the preferred embodiment surface  36  is an annular groove having a radius of curvature adapted to receive balls  44 , and surfaces  38  and  40  each having planar annular portions  38   a  and  40   a  (best seen in  FIG. 5 ). 
   Grabber means  20  has an outer cylindrical retaining member  50  that is provided with a fixed radial post  52 . Another radial post  54  is secured to the distal, first annular ring  30 . Retaining member  50  is secured to a spring member (not shown) interposed between the distal annular ring  30  and cylindrical member  50 . Cylindrical member  50  is rotatable about axis  46  when a user squeezes posts  52  and  54  together because post  54  is able to move in arcuate slot  58 . The circular opening  60  of flange  61  formed at the distal end of cylindrical member  50  has a diameter large enough to accept therethrough the eyepiece  62  of endoscope  10 . Three arcuate and radially pivotable retaining arms  64   a ,  64   b  and  64   c  (the latter being hidden from view in  FIG. 3 ) are pivotably attached to the distal surface of distal annular ring  30  at points  65   a ,  65   b  and  65   c  (best seen in  FIG. 2 ). Each arm has a longitudinally extending pin (not shown) riding in a radially and laterally extending slot (not shown) in the distal flange  61  of cylindrical retaining member  50 . As posts  52  and  54  are squeezed together, the relative rotation between the retaining member  50  and distal annular ring  30  causes the retaining arms to pivot about their attachment points to clear opening  60  to receive eyepiece  62 . Releasing pressure on the posts  52  and  54  allows arms  64   a ,  64   b  and  64   c  to move radially inwardly behind the eyepiece to lock the eyepiece of the endoscope within the cylindrical retaining member  50 . The arms, in cooperation with radially inwardly extending tabs  70   a ,  70   b  and  70   c  on distal ring  30  (best seen in  FIG. 6 ) serve to position the eyepiece at the proper axial location relative to the optical components in camera  12 . Once the scope is so situated, it may rotate about axis  46  along with the distal annular ring  30 . 
   The proximal most rim  72  of annular ring  30  is provided with a plurality of radially inwardly extending slots  74 . Slots  74  extend longitudinally and in the preferred embodiment are open and proximally facing at rim  72 . 
   Proximally situated second annular ring  32  has an axially aligned opening  76  adapted to receive the distal end of camera  12 . Opening  76  is threaded at its proximal end to receive a camera adapter or to receive a camera mount directly. Ring  32  has an outer cylindrical annular wall  77  and a transverse proximal wall  78 , the latter provided with a plurality of circumferentially arranged ventilation apertures  80 . Annular wall  77  has a length along axis  46  sufficient to properly place bearing race surface  38  relative to bearing surfaces  36  and  40  to define race  42  when the proximal ring  32  is threadably engaged with lateral ring  34 . When fully assembled, the distally facing side  82  of proximal wall  78  will be adjacent to but spaced from the proximal most end of rim  72 , and all surfaces  36 ,  38  and  40  will be contiguous with balls  44 . 
   Second annular ring  32  carries a locking mechanism  90  which serves to prevent the relative rotation between the camera mount means  22  and the grabber means  20  by engaging a pivotable projection with the slots  74 . Locking mechanism  90 , best seen in  FIGS. 4 ,  12 ,  13 , and  14 , comprises a toggle lever  92  pivotably secured to and adjacent the radially outer surface of the proximal side of ring  32  by a shoulder screw  94 . Ring  32  has a screw-receiving threaded bore  96 . Lever  92  is thus situated transversely to axis  46 . The transverse length L of lever  92  is long enough so that when the lever is pivoted a predetermined amount clockwise or counterclockwise about its axis  98 , one corner  100  or  101  will extend radially beyond the outer surface of annular ring  34 . This enables one or the other corner of lever  92  to be easily pushed radially inwardly by the thumb (or other finger) of the hand holding the camera to toggle the lever from one extreme to the other, e.g. from locked to unlocked. Lever  92  is situated a predetermined arcuate lateral distance  93  from the top of the coupler to position it for easy accessibility. 
   The proximally facing surface  102  of lever  92  is provided with icons  104  and  106  (preferably molded, machined or otherwise form on the surface, or placed via a decal, paint, etc.) depicting a locked or unlocked condition and the direction in which the adjacent corner  100  or  101  must be pushed to achieve the desired condition. 
   The distally facing surface  108  of lever  92  is provided with a pair of detents  110  and  111 , and a pair of detents  112  and  113 . These detents are designed to cooperate with bores  114  and  115  formed in the proximally facing surface of ring  32 , and with balls  116 ,  117  and springs  118 ,  119  to frictionally engage lever  92  and hold it in the locked or unlocked position. In the preferred embodiment balls  116  and  117  each have a diameter of 0.063 inches and are made of ceramic. (Balls  116 ,  117  and balls  44  are, in the preferred embodiment, also coated with a high temperature grease.) The distally facing surface  108  is also provided with a projection  120  extending distally and having an interference member or tooth  122 . Proximal surface  78  of annular ring  32  is provided with an aperture  124  in order to receive projection  120  and tooth  122  therethrough and enable the tooth to be positioned radially inwardly of slots  74 . When lever  92  is pivoted into a locked position, tooth  122  engages one of the slots  74 , thus preventing relative rotation between the two sides of coupler  14 . 
   It will be understood by those skilled in the art that numerous improvements and modifications may be made to the preferred embodiment of the invention disclosed herein without departing from the spirit and scope thereof.