Abstract:
This invention relates to a surgical irrigation system having an improved reusable, motorized console and a separable/attachable irrigation pump cassette, including, at least in one embodiment improved mechanical and electrical inner-connection structure therebetween, and at least in one embodiment improved pump priming structure and methods.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application claims the benefit of U.S. Provisional Application Ser. No. 60/750,102, filed Dec. 14, 2005, which is incorporated herein in its entirety. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to a surgical irrigation system, and more particularly relates to an irrigation apparatus having a pump cassette separable from the power unit.  
       BACKGROUND OF THE INVENTION  
       [0003]     Surgical irrigation apparatus, of the type having portions engageable with a surgical site and including a pumping member separably engageable with a power unit including a motor for driving the pumping member, is known in the prior art. A number of examples exist. However, those of which applicants are aware have variously provided room for improvement in terms, for example, of performance, convenience of use, reliability, cost, etc.  
         [0004]     Accordingly, the objects and purposes of the invention include providing an improved apparatus of the aforementioned general type.  
         [0005]     Further objects and purposes of the invention will be apparent to persons of ordinary skill in this art upon reading the accompanying description and inspecting the accompanying drawings.  
       SUMMARY OF THE INVENTION  
       [0006]     This invention relates to a surgical irrigation system having an improved reusable motorized console and separable/attachable irrigation pump cassette, at least in one embodiment with improved mechanical and electrical inter-connecting structure therebetween and in at least one embodiment with pump priming structure and methods.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]      FIG. 1  is a pictorial, substantially schematic view of a surgical suction irrigation system embodying the invention.  
         [0008]      FIG. 2  is a pictorial view, taken substantially from the front and right side, of the surgical irrigation apparatus of  FIG. 1 .  
         [0009]      FIG. 2A  is a front view of the  FIG. 2  console  14  and cassette unit.  
         [0010]      FIG. 2B  is a central cross sectional view substantially taken on the line  2 B- 2 B of  FIG. 2A .  
         [0011]      FIG. 2C  is a cross sectional view substantially taken on the line  2 C- 2 C of  FIG. 2A .  
         [0012]      FIG. 2D  is a cross sectional view substantially taken on the line  2 D- 2 D of  FIG. 2A .  
         [0013]      FIG. 3  is a pictorial view of the  FIG. 2  apparatus taken substantially from the rear thereof and showing mounting thereof on a conventional, upstanding, irrigation liquid bag support pole.  
         [0014]      FIG. 4  is a pictorial view taken from the front and left side, of the console, or power, unit of the  FIG. 2  apparatus, namely with the  FIG. 2  pump cassette removed.  
         [0015]      FIG. 5  is a pictorial view taken substantially from the rear and left side, of the  FIG. 4  power unit.  
         [0016]      FIG. 6  is an exploded pictorial view of the  FIG. 4  power unit taken substantially from the left side and front and with the front end rear console assemblies thereof separated.  
         [0017]      FIG. 7  is a pictorial view of the front console assembly of  FIG. 6 , taken substantially from the front thereof.  
         [0018]      FIG. 8  is a further pictorial view of the  FIG. 6  front console assembly taken substantially from the rear thereof.  
         [0019]      FIG. 9  is an exploded pictorial view of the  FIG. 7  front console assembly.  
         [0020]      FIG. 10  is a pictorial view, taken substantially from the rear thereof, of the front chassis of the  FIG. 9  front console assembly.  
         [0021]      FIG. 11  is a central cross sectional view, substantially taken on the line  11 - 11 , of  FIG. 10 .  
         [0022]      FIG. 12  is a rear view of the  FIG. 8  front console assembly.  
         [0023]      FIG. 13  is a pictorial view of the  FIG. 6  rear console assembly taken substantially from the rear and left side thereof.  
         [0024]      FIG. 14  is a further pictorial view of the  FIG. 13  rear console assembly but taken substantially from the rear and right side thereof.  
         [0025]      FIG. 15  is an exploded pictorial view of the  FIG. 14  rear console assembly.  
         [0026]      FIG. 16  is a pictorial view of the rear chassis of the  FIG. 15  rear console assembly, taken substantially from the rear and left side thereof.  
         [0027]      FIG. 17  is a central cross sectional view taken substantially on the line  17 - 17  of  FIG. 16 .  
         [0028]      FIG. 18  is a pictorial view of the battery cover of  FIG. 15  taken substantially from the bottom and rear thereof.  
         [0029]      FIG. 19  is a bottom view of the battery pack of  FIG. 15 .  
         [0030]      FIG. 19A  is a schematic view of the  FIG. 19  battery pack.  
         [0031]      FIG. 20  is a pictorial view of the clamp of  FIG. 15 .  
         [0032]      FIG. 21  is an exploded pictorial view of the cassette unit of  FIG. 1 .  
         [0033]      FIG. 22  is a bottom view of the cassette body of  FIG. 21 .  
         [0034]      FIG. 23  is a central cross sectional view substantially taken on the line  23 - 23  of  FIG. 22 .  
         [0035]      FIG. 23A  is a front view of the  FIG. 21  cassette body.  
         [0036]      FIG. 24  is a right side view of the  FIG. 21  cassette body.  
         [0037]      FIG. 25  is a cross sectional view substantially taken on the line  25 - 25  of  FIG. 24 .  
         [0038]      FIG. 26  is a cross sectional view substantially taken on the line  26 - 26  of  FIG. 24 .  
         [0039]      FIG. 27  is a rear view of the cassette cover subassembly of  FIG. 21 .  
         [0040]      FIG. 28  is a front view of the  FIG. 27  cassette cover subassembly.  
         [0041]      FIG. 29  is an exploded pictorial view of the cassette cover subassembly of  FIG. 21 .  
         [0042]      FIG. 29A  is a cross sectional view substantially taken on the line  29 A- 29 A of  FIG. 28  and including assembled components of the cassette body  450  and cassette cover subassembly  451 .  
         [0043]      FIG. 30  is a front view of the cassette cover of  FIG. 29 .  
         [0044]      FIG. 31  is a central cross sectional view substantially taken on the line  31 - 31  of  FIG. 30 , with the upper one of the radial webs shown in relief.  
         [0045]      FIG. 32  is a central cross sectional view of the motor coupler of  FIG. 9 , and substantially as taken on the line  32 - 32  of  FIG. 32A .  
         [0046]      FIG. 32A  is a front end view of the motor coupler of  FIG. 32 .  
         [0047]      FIG. 33  is a side view of the cassette coupler of  FIG. 29 .  
         [0048]      FIG. 33A  is a central cross sectional view substantially taken on the line  33 A- 33 A of  FIG. 33 .  
         [0049]      FIG. 33B  is a rear end view of the cassette coupler of  FIG. 29 .  
         [0050]      FIG. 34  is a schematic block diagram of the operating circuitry of the  FIG. 1  system.  
         [0051]      FIG. 34A  is a schematic diagram of a simplified control for the  FIG. 1  system.  
         [0052]      FIG. 35  is a flowchart of a method for priming the pump, either manually or by means of the  FIG. 34  control. 
     
    
       [0053]     In the following description, the words up, down, right, left, front and rear, and derivatives thereof shall apply to directions in a given drawing figure and shall not be limiting.  
       DETAILED DESCRIPTION  
       [0054]     A surgical suction irrigation system  10  ( FIG. 1 ) comprises a surgical irrigation apparatus  12  comprising a console (or power unit)  14  and a cassette unit  16  releasably fixable to and removable from the console  14 . The console  14  is intended to be reusable, in that it does not come in to contact with liquids that in turn make contact the patient at the surgical site on the patient, and because there is an economic saving in being able to reuse the console in subsequent surgeries. On the other hand, the cassette unit  16  is intended to be non reusable and disposable after use in a single surgery because it does handle irrigation liquid which may come into contact with the patient at the surgical site thereon, thus avoiding the risk of cross contamination from patient to patient and wherein the cassette unit may be manufactured at relatively low cost to minimize the economic impact of discarding after a single surgical use. However, it will be understood that the present invention is not limited to reusability or non-reusability of parts of the surgical system  10 .  
         [0055]      FIG. 1  schematically shows the surgical irrigation apparatus  12  in a typical position of use. As seen, the console  14  ( FIGS. 1-3 ) is clamped at a desired height on a conventional upstanding (usually portable) support pole assembly  20 , comprising a normally floor supported base  21 , a pole  22  upstanding therefrom, laterally extending arms  23  fixed adjacent the upper end of the pole and adapted to pendantly support one or more (here two) irrigation liquid containers, typically bags,  25  having respective conventional fittings  27  communicating through the bottom thereof.  
         [0056]     The cassette unit  16  includes a pump cassette  40  releasably fixed to the console  14 , and irrigation liquid inlet tube  42  for receiving irrigation liquid from at least one of the irrigation liquid bags  25  (here through a “Y” tube  44 ) and flow control structure such as conventional manually operable tube pinch clamps, not shown, such that the surgical team can control gravity flow of irrigation liquid from the irrigation liquid bags to the irrigation liquid inlet tube  42  in a conventional matter.  
         [0057]     The cassette unit  16  further includes an irrigation liquid outlet tube  46  to a surgical irrigation handpiece  50  of the type normally handled and controlled by a member of the surgical team (e.g. surgeon) for selectively applying irrigation liquid to a surgical site SS on a patient P. While the use of surgical irrigation handpieces of a variety of types is contemplated, preferred examples include those disclosed in U.S. Pat. Nos. 6,213,970 and 6,652,488 assigned to the assignee of the present invention.  
         [0058]     The disclosure in those patents is incorporated by reference herein. Briefly summarizing however, the handpieces disclosed therein comprise, as schematically indicated in  FIG. 1 , a handpiece body  52  containing a normally closed, manually openable push button irrigation valve  54  and a normally closed, manually openable, push button suction valve  56  and having a forward extending, elongated tubular tip  58  insertable in a surgical site SS of a surgery patient P. A conventional suction tube  60  connects the handpiece  50  to a conventional suction source SUC. Thus, manual depression of the push button irrigation valve  54  directs a desired flow of irrigation liquid from the pump cassette  40  and the irrigation liquid outlet tube  46  through irrigation valve  54  and the tip  58  to the surgical site SS. On the other hand, manual depression of the push button suction valve  56  opens same to apply a desired level of draw liquid and other flowable material from the surgical site SS through the tip  58 , handpiece suction valve  56 , and suction tube  60  to the suction source SUC. The latter preferably conventionally includes a suitable suction container SC, maintained at subatmospheric pressure, as by connection to a conventional suction terminal ST in the surgical operating room wall for receiving and storing, for later disposal the flow of materials from the surgical site SS. Also, in the above listed patents incorporated by reference herein, the handpiece  50  includes a normally closed switch SW operatively connected by a multi-conductor (at least 2 wire) cable  64  to the surgical irrigation apparatus  12  in a manner hereafter more fully discussed.  
         [0059]     It will be understood that the present invention is not limited to any particular type of handpiece or other connection to the surgical site SS, but rather that the handpiece  50  above discussed is disclosed for purposes of illustration only.  
         [0060]     Turning now in more detail to the console  14  ( FIGS. 4-6 ), same comprises a front console assembly  70  and a rear console assembly  71 .  
         [0061]     The front console assembly  70  ( FIGS. 7-11 ) comprises a front chassis  80  of generally rectilinear, box-like, rear opening shape, comprising top and bottom walls  81  and  82 , side walls  83 , and a front wall  85 . A generally centered, generally rectilinear, shallow recess  90  occupies most of the front of the front chassis, leaving a relatively thin border of front wall  85  bounding same. The front facing wall  91  of the recess  90  is pierced by a pair of generally rectangular, upstanding, upper holes  92  and  93  and, therebelow, a cassette receiving recess  96 . The recess  96  is of generally rectilinear, upstanding form, though with a convexly rounded top wall  97 . A generally tubular shell  100  opens through and extends forwardly from the back wall  98  of the cassette receiving recess  96 .  
         [0062]     As seen from the rear in  FIG. 10 , the cassette receiving recess  96  forms a correspondingly shaped, rearwardly extending boss  99 , beyond which the front chassis walls  81 ,  82 , and  83  rearwardly extend. Upstanding, rectangular cross-section bezels  102  ( FIGS. 10 and 11 ) protrude slightly rearward from the boss  99  and define forward/rearward opening through slots  103  for cassette mounting purposes as hereafter described. The bezels  102  are disposed at opposite sides of the boss  99  and flank the tubular shell  100  in laterally spaced relation on opposite sides thereof. The tubular shell  100  has a coaxial bezel  106  extending rearwardly from the boss rear wall  98  substantially to the extent of the cassette mounting bezels  102 , and a central through hole  105 . The central through hole  105  has an increased diameter, forward facing recess in the portion of the tubular shell  100  which extends forward from the back wall  98  ( FIG. 11 ).  
         [0063]     A laterally elongate, generally rectilinear, rearward opening battery receiving well  114  ( FIGS. 10 and 11 ) is defined by a perimeter wall  115  extending rearward from the bottom portion of the front chassis front wall  85  and front facing recess wall  91  and laterally spaced, upstanding, battery backing ribs  116 , as well as an upstanding divider wall  117  adjacent the leftward ( FIG. 10 ) end of the battery receiving well  114 . Webs  118  extend laterally and downwardly from the battery receiving well peripheral wall  115  to rigidly locate the latter within the front chassis  80 .  
         [0064]     To facilitate precise location of the cassette unit  16  on the console  14 , the peripheral wall of the forward facing recess  107  has its exterior annular surface  109  convergently angled forwardly at an angle A 2 , preferably in the range of 2 to 4 degrees, for example 3 degrees.  
         [0065]     The front console assembly  70  further includes a motor mount plate  130  ( FIG. 9 ), generally of laterally extended rectilinear profile, having laterally spaced upper lobes  132  and a depending, central, lower lobe  133 . A hole  134  in the lower lobe  133  receives a generally cylindrical proximity sensor  136 , which is externally threaded and fixed to the plate  130  by sandwiching front and rear nuts  137 , such that a portion of the sensor protrudes forwardly from the mounting plate  130  to engage a shallow rear facing circular recess  138  ( FIG. 10 ) rearwardly opening in the back wall  98  ( FIG. 10 ) of the front chassis  80 .  
         [0066]     An electric rotate motor  144  ( FIG. 9 ) has a reduced diameter front boss  145  from which coaxially extends the rotatable shaft  146  of the motor. A resilient motor vibration damping gasket  148  sleeves snugly over the front boss  145  and rests against the rear face of the motor mounting plate  130 . The boss  145  and shaft  146  are forwardly received through a generally central hole  150  in the plate  130 , with the shaft  148  extending forwardly well beyond the plate  130 . Screws  152  extend rearwardly through screw holes laterally flanking the hole  150  in the plate  130 , through corresponding holes in the gasket  148 , and threadedly engage the front end of the motor  144  to fixedly cantilever the motor  144  from the rear face of the plate  130 .  
         [0067]     A motor coupler  158 , hereafter more fully described, is fixed to the front end of the motor shaft  146 , so as to be rotatable thereby.  
         [0068]     The immediately above described proximity sensor/motor subassembly  130 - 158  is, during assembly of the front console assembly  70 , fixed to the front chassis  80  by movement forward (rightward in  FIG. 9 ) toward the back of the front chassis  80 , to rest the front face of the plate  130  against internally threaded lugs  162  ( FIG. 10 ). The latter extend rearward preferably into coplanar relation with the rear edges of the bezels  102  and loosely circumferentially surround the central bezel  106 . Screws  164  ( FIG. 9 ) extend through suitable holes in the top and bottom portions of the motor mounting plate  130  and thread into the lugs  162  ( FIG. 10 ) to mount the sensor/motor subassembly  130 - 158  fixedly against the lugs  162  and bezels  102 , with the motor shaft  146  and motor coupler  158  extending forward through the central through hole  105  and forward facing recess  107  of the front chassis  80  generally in the manner indicated in FIGS.  4 ,  6 - 8  and  12 .  
         [0069]     A pair of console face plate contacts  168 , here in the form of electrically conductive, panhead machine screws, extend, as generally indicated in  FIGS. 7-9 , rearwardly through holes  169  ( FIG. 10 ) in the back wall  98  of the boss  99 . Nuts  172  ( FIG. 9 ), preferably with lock washers  173 , fix the contacts  168  in place and connect same to the bared ends of corresponding electrical conductors  174  and  175  ( FIG. 12 ) for purposes appearing hereafter.  
         [0070]     A control board  180  ( FIG. 9 ) carries control circuitry hereafter discussed on its rear face and on its front face carries a conventional digital flow rate display  181  and battery level display  182 . To assemble, the control board  180  is inserted forward into the upper part of the open rear of the front chassis  80 , into contact with webs  184  ( FIG. 10 ) fixed to and extending rearward from the front wall  85  of the front chassis  80  and into supported contact with bosses  186  protruding rearward from the wall  91 . The displays  181  and  182  extend into the holes  93  and  92 , respectively, in the wall  91 , so as to be visible from in front of the front chassis  80 . Screws  188  ( FIG. 9 ) extend through holes  189  in the control board  180  and are threaded into threaded holes in the aforementioned bosses  186  to fix the control board  180  in the open rear portion of the front chassis  80  adjacent the top wall  81  thereof, as generally seen in  FIG. 8 .  
         [0071]     A cassette pump console membrane  194  ( FIG. 9 ) is sized to fit in the main recess  90  ( FIG. 9 ) of the front chassis  80  and has a through hole  196  sized and shaped and located to conform to the cassette receiving recess  96 . The membrane  194  in its upper portion includes (1) a conventional membrane-type, finger pressure activated, upward shifting and downward shifting actuator  198 , and immediately to the left thereof (2) a transparent window  199  through which the digital flow rate display  181  is visible, (3) a transparent window  200  through which the battery level display is visible, and (4) a battery check switch actuator  201  (preferably another membrane-type switch) finger pressure activated for manual checking of battery condition, e.g. when the apparatus is off and prior to use. The membrane  194  is fixed in any convenient manner, such as adhesive bonding, to the front facing wall  91 , within the main recess  90 .  
         [0072]     The console face plate contacts  168  ( FIG. 12 ), a set of electrical energizing contacts  204  on the motor  144 , a battery connector  206 , and the proximity sensor  136  are connected by suitable wiring generally indicated at  210  to the control board  180  ( FIG. 9 ) in a manner hereafter discussed.  
         [0073]     Turning now to the rear console assembly  71  ( FIGS. 13-15 ), same comprises an open front, generally rectilinear box-like rear chassis  250  having a top wall  251 , a bottom wall  252 , side walls  253  and a rear wall  254 . In the embodiment shown, the rear wall  254  is concavely curved about a distant vertical axis not shown.  
         [0074]     The corners and edges of the front chassis  80  and rear chassis  250  are preferably curved on a relatively large radius, as shown, for comfort and ease of handling.  
         [0075]     The rear chassis rear wall  254  ( FIG. 16  and  17 ) in its upper portion, has a rear opening, laterally extending, generally rectilinear clamp recess  260  having an inboard base wall  261  and perimeter walls  262 . Stiffening webs  263  ( FIGS. 15 and 17 ) extend from the clamp recess perimeter wall  262  to the rear chassis rear wall  254  for stiffening purposes. Generally rectilinear struts  266  extent rearwardly from the rear wall  254  at the top and bottom edges of the clamp recess  260  and are laterally spaced apart so as to lie substantially flush with the plane of the laterally imposed ones of the recess perimeter walls  262 . The struts  266  have vertically opposed, substantially parallel faces  267  which are preferably flush with the opposed top and bottom ones of the recess perimeter walls  262 . In the preferred embodiment shown, the struts have faces which are vertically remote from the clamp recess  260  and are preferably curved in approximately an S-profile, so as to be convexly rounded at their outer (rearward) ends and concavely curved into substantially filleted engagement with the chassis rear wall  254 , as generally indicated at  268 . The recess  260  and struts  266  define a clamp mount generally indicated at  270 .  
         [0076]     An AC power cord mount  280  ( FIG. 16 ) comprises a preferably rectangular, substantially square hole  281  through the rear wall  254 , immediately to the right (in  FIG. 16 ) of the clamp mount  270 . The hole  281  opens rearward through a substantially diamond shaped recess  282  in the chassis rear wall  254 , which defines upper and lower, substantially triangular shape, rearward facing flats  284 . A bonnet brim  286  extends rearward from the chassis rear wall  254  flush with the laterally opposed side and top walls of the recess  282 , in a manner to, for example, deflect falling water droplets from entry into the hole  281  and recess  282 .  
         [0077]     A laterally elongate, generally rectilinear, battery receiving passage  290  ( FIG. 16 ) opens through the lower portion of the back wall  254 . The passage  290  is located, shaped and sized to be a substantially flush rearward extension of the battery receiving well  114  of  FIGS. 10 and 11 . Indeed, the well  114  and passage  290  are preferably somewhat mutually telescoped upon assembling together of the front and rear console assemblies  70  and  71 . More particularly, the peripheral wall  291  ( FIG. 17 ) of the passage  290  has an axially relatively short, inner, front facing recess  292  that snugly telescopingly receives the rear edge portion  119  ( FIG. 11 ) of the well peripheral wall  115  ( FIG. 11 ). As seen in  FIG. 11 , the portion  119  projects slightly rearwardly beyond the top, bottom, and side walls  81 - 83  of the front chassis  80  to snugly fit in the recess  292  ( FIG. 17 ). The result is that, in the assembled console  14 , the interior surface of the passage peripheral wall  291  is a smoothly flush rearward extension of the interior surface of the peripheral wall  115  of the battery receiving well  114  ( FIG. 11 ). In the preferred embodiment shown, webs  294  extend from the passage peripheral wall  291  laterally and downwardly to the side and bottom walls  253  and  252  of the rear chassis  250  to rigidify the location of the peripheral wall  291  within the confines of the rear chassis  250 .  
         [0078]     A shallow, box-like, generally rectilinear, forward opening battery cover  300  ( FIGS. 15 and 18 ) is laterally elongate and has a back wall  304  from which forwardly protrude top and bottom walls  301  and  302  and upstanding side walls  303 . The battery cover  300  is sized and shaped to install in the rear portion of the battery receiving passage  290 , such that the battery cover bottom and back walls  302  and  304  are flush with the rear chassis bottom and back walls  252  and  254 , as seen in  FIG. 13 . A rectangular cross section lip  319  extends along and protrudes perpendicularly from the forward edge of the battery cover top and side walls  301  and  303  and, upon upward movement of the battery cover  300  into closing relation with the rear portion of the passage  290 , is snugly but slideably received in a corresponding guide groove  314  ( FIG. 17 ) opening downwardly and laterally inwardly from the upper end wall portion  296  and side wall portions  297  of the battery receiving passage peripheral wall  291 , so as to releasably fix the battery cover  300  against upward, sideward and forward/rearward movement out of its battery receiving passage closing position of  FIG. 13 . The bottom wall  302  of the cover  300  has a forward extending portion, or ledge,  318  ( FIG. 18 ) including a central tip  319  having a preferably countersunk through hole  320 . With the battery cover  300  installed on the rear chassis  250  as in  FIG. 13 , the tip  319  is received in a correspondingly profiled rearward and downward opening recess  322  ( FIGS. 16 and 17 ) in the bottom wall  252  of the rear chassis  250  and is releasably retained by any convenient means such as an upwardly inserted screw  323 . If desired, and as seen in  FIG. 15 , a semirigid plastic label  324 , e.g. to warn the users of the need to connect the batteries before use, may be fixed by the screw  323  to the tip  319 .  
         [0079]     Generally L-profile webs  328  ( FIG. 15 ) are laterally spaced and extend forward and upward from the bottom and back walls  302  and  304  of the battery cover  300  to block rearward and downward shifting of a battery pack  330  ( FIGS. 15 and 19 ).  
         [0080]     In the embodiments shown, the battery pack  330  ( FIGS. 15 and 19 ) comprises a number of cells sufficient to provide the desired operating voltage, here for example 14 cells nominally rated at 1.2 volts apiece for a total nominal rating of 16.8 volts. While the battery pack  330  may be comprised of non-rechargeable (e.g. alkaline) cells, rechargeable cells are preferred, particularly conventional nickel metal hydride (NiMH) cells in view of their low toxicity, relatively high ampere hour capacity, and relatively flat voltage output under load and over a relatively high percentage of their total discharge capacity. Conventional AA cells are compact and widely available at low cost and so are preferred. In the embodiments shown, the individual cells  331  are packaged in a substantially brick-like form comprising two parallel, side-by-side rows of 7 cells apiece, fixedly secured together by any convenient means, for example heat shrink film (not shown).  
         [0081]     Electrical connections between the cells  331  are covered by the mentioned heat shrink film, as well as by padding preferably in the form of conventional adhesive backed foam sheets (sometime referred to as foam tape)  334  which snugly and resiliently support the battery pack  331  when installed in the battery receiving passage  290  ( FIG. 6 ) and battery receiving well  114  ( FIG. 14 ) of the front chassis  80 , upon assembly of the front and rear console assemblies  70  and  71  as appearing in  FIGS. 4 and 5 .  
         [0082]     The battery pack  330  has insulated output wires  338  ( FIGS. 9 and 19 ) variously of positive and negative polarity and which are connected to circuitry (hereinafter discussed) by any convenient means, here schematically indicated by a suitably mechanically lockable and releasable connector  339 .  
         [0083]     The base wall  261 , above mentioned with respect to the clamp recess  260 , mounts several interior and exterior components as immediately hereafter discussed with reference to  FIGS. 14 and 15 .  
         [0084]     A clamp assembly  350  ( FIG. 15 ) comprises a generally C-shaped clamp base  351  having a laterally extending bight wall  352 , from the ends of which rearwardly extend respective arms  354  and  355 . A palm plate  356  angles rearwardly and laterally inwardly from the rear end of the arm  355 . A clamp screw  360  extends threadedly through a threaded opening in a palm plate  356  and angles forwardly and toward to the joinder of the clamp base and arm  354 . The outboard end of the clamp screw  360  defines a hand actuable knob  361 . The clamp screw  360  at inboard end preferably fixedly carries a non-marring (e.g. rigid or resilient plastic) tip  362 . The clamp assembly  350 , as seen in  FIG. 3 , adjustably and releasably supports the surgical irrigation apparatus  12  on a support, such as the above mentioned support pole  22 , by pocketing the latter in the pocket defined by the joinder of the clamp assembly bight wall  352  and arm  354  and holding same there by threading the inboard end of the screw  360  end into contact with such pole  22 .  
         [0085]     Friction pads  364  ( FIG. 15 ) of any convenient surface textured, high friction, and preferably generally resilient, rubber-like material, here rectangular in shape, are fixed, conveniently by adhesive bonding, to the rear and laterally inboard faces of the bight wall  351  and arm  355  of the clamp assembly  350 , adjacent to join of the bight wall  351  and arm  355 , to frictionally engage the pole  22  ( FIG. 3 ), and thereby assist the tightened screw  360  in fixedly clamping the console  14  to the pole  22 . The bight wall  351  of the clamp assembly is snugly received in the clamp recess  260  ( FIG. 16 ) against the base wall  261  thereof, with the arms  354  and  355  snugly vertically sandwiched between corresponding laterally spaced pairs of the struts  266 , in the manner seen in  FIG. 5 .  
         [0086]     Flat head mounting screws  370  ( FIG. 15 ) extend rearward through countersunk holes in the substantially rectangular bottom portion of a generally inverted, T-profile clamp mounting plate  371  and thence through holes in the base wall  261  of the clamp recess  260  and thread in to forward facing holes  374  in the clamp base  351  (located in the present example at the four corners of the base  351 ) to fix the clamp assembly  350  in the clamp recess  260  in the back of the rear chassis  250 , as seen for example in  FIG. 5 .  
         [0087]     A power supply unit  384  ( FIG. 15 ) comprises a substantially rectangular, laterally extended circuit board  386 . The board  386  carries on its forward face suitable power supply circuitry, indicated schematically in  FIG. 15  by the rectilinear block  385 , and which faces forward from the circuit board  386 . An electrical insulator sheet  390  of suitable insulative material, such as TEFLON®, faces forward toward the rear face of the circuit board  386 . The spacers  391  allow for proper spacing between the power supply and the electrical insulator sheet. Screws  392  extend rearwardly through holes in the corners of the circuit board  386 , the washer-like spacers  391 , and thread into the front ends of bosses  394  extending forward from the rear wall  254  of the rear chassis  250 . The holes in the insulative sheet  390  slide over bosses  394  on the rear chassis and is held in position between the power supply and the rear chassis. The bosses  394  engage ones of the above mentioned webs  263 . The thus installed power supply unit  384  is seen in  FIG. 14 .  
         [0088]     The relatively massive external C-shaped clamp base  351 , the screws  370  and  377 , and the plate  371  are preferably of heat conductive metal. In the embodiment shown, the clamp mounting plate  371  may include a laterally narrow, upstanding tab  376  ( FIGS. 14 and 15 ) carrying a screw  377 , which in one unit constructed according to the invention enabled use of the exterior clamp base  351  as a heat sink for a heat generating component of the power supply  384 , here exemplified by a power resistor  1000  ( FIGS. 14 and 34 A across the power supply output.  
         [0089]     A conventional power module  400  ( FIG. 15 ), intended for connection to a remote conventional external power source (e.g. wall socket), such as a 110 volt AC source in the United States, may be of any commercially available type. In the embodiment shown, the power entry module  400  is a model 5220.0123.3 available from Schurter, Inc. located at Santa Rosa, Calif. In the example shown, same comprises an insulated body  404  having a rear opening recess  402  ( FIG. 13 ) and a frontward and laterally opening notch  403  ( FIG. 15 ). The body includes a portion  406  for receiving conventional fuses  407  ( FIG. 15 ) interposed between rearward extending electric power inlet conductors  408  ( FIG. 13 ) in the recess  402  and output conductors  409  in the notch  403 . The inlet conductors  408  are conventionally shaped, spaced and oriented for connection to a conventional “house” power line e.g., in the United States a 110 volt AC wall plug, through a conventional power cord unit  420  ( FIGS. 1 and 3 ). The power entry module  400  here includes upward and downward extending ears  410  ( FIG. 15 ). Screws  411  extend forwardly through holes in the ears  410  and into threaded engagement with rear facing holes  412  ( FIG. 16 ) in the triangular flats  284  in the AC power cord mount  280 .  
         [0090]     A flexible cord holder strap  430  ( FIG. 15 ) is pivotally fixed at its upper end by a screw  431  on the rear face of the rear wall  254  of the rear chassis  250 . The screw  431  extends through a hole in the upper end portion of the strap  430 , and thence through a hole  432  ( FIG. 16 ) in the chassis rear wall  254  for threaded retention by a nut  433  ( FIG. 14 ), which is preferably locked by lock washer or is of conventional self-locking type. Screw  431  has an annularly grooved axially elongated head  434  for receiving in the widened end of a keyhole  436  ( FIG. 15 ) adjacent the lower end of the strap  430 , such that the strap can be folded upon itself, as a loop, as seen in  FIG. 3 . When it is desired to shorten the power cord, loops of the mid-portion of the power cord unit  420  may be fixed to the rear face of the console  14  by means of the strap  430 .  
         [0091]     To assemble together the front and rear console assemblies  70  and  71  ( FIGS. 4 and 5 ) to form the console  14 , screws  440  ( FIG. 6 ), preferably provided with washers  441 , are inserted forwardly into deeply recessed rearward facing holes  442  extending forward through bosses  443  preferably located at the four corners of the box-like rear chassis  250  ( FIG. 6 ) and thread into rearward opening holes  444  ( FIGS. 8 and 10 ) extending forward into bosses  445  preferably disposed at the four corners of the interior of the box-line front chassis  80 .  
         [0092]     Turning now to the cassette unit  16  ( FIG. 21 ), the pump cassette  40  comprises a cassette body  450  and a cassette cover subassembly  451 .  
         [0093]     The cassette body  450  is generally box-like in shape, opening rearwardly (leftwardly in  FIG. 21 ) and comprising a bottom wall  460 , laterally spaced upstanding side walls  461  and a convexly cylindrically rounded top wall  462 , as well as a front wall  464 .  
         [0094]     The cassette body  450  ( FIGS. 21-26 ) includes a cup-like, rear opening pump chamber  470  having a generally circularly cylindrical peripheral wall  471  extending rearward from the cassette body front wall  464 . The pump chamber  470  comprises a rear opening cavity  482  bounded by a generally cylindrical front peripheral surface  474 , a rear facing annular step  472 , and a generally cylindrical rear inner peripheral surface  477  of increased diameter. A concavely curved annular fillet  479  connects the front peripheral surface  474  to a front end face  475 , which faces rearward toward the open end of the pump chamber cavity  482 . The step  472  extends radially inward from the front inner peripheral surface to the rear inner peripheral surface. The cassette body front wall  464  forms and extends forward from the pump cavity front end face  475 .  
         [0095]     The pump chamber peripheral wall  471  extends rearward from the cassette body front wall  464  almost to the rear end of the cassette body bottom, side, and top walls  460 ,  461  and  462 , which extend rearward slightly therebeyond, as seen for example in  FIGS. 21, 23 , and  26 . The pump chamber peripheral wall  471  is radially spaced somewhat from the cassette body side and top walls  461  and  462  and is fixed thereto by a radially upwardly extending, axially elongate fin  488  ( FIG. 23A ) and by laterally extending, axially elongate fins  490 , respectively. The fins  490  comprise a substantially coplanar horizontal upper pair and a substantially coplanar horizontal extending lower pair, which pairs are spaced above and below the central axis of the pump chamber  470 . The pump chamber peripheral wall  471  is substantially more greatly spaced above the cassette body bottom wall  460  and is braced with respect thereto by laterally spaced, vertically and axially extending fins  492  ( FIGS. 23 and 23 A). Additional stiffening, or reinforcing, fins may be provided as desired, for example as indicated at  493  and  494  in  FIG. 23A .  
         [0096]     The cassette body front wall  464  includes a forwardly thickened top portion  500  ( FIG. 23 ). An irrigation liquid inlet recess  502  opens upward in the front wall top portion  500 , is substantially of circular cylindrical form, has a preferably vertical central axis coplanar with the horizontal central axis of the pump chamber  470  and communicates with the front end of the pump chamber cavity  482  by means of a preferably right angle elbow passage  504 . Preferably, a radially narrow, upward facing annular step  505  marks the joinder of the recess  502  to the top of the elbow passage  504 . The lower, rear facing end of the elbow passage  504  is preferably coaxial with the central length axis of the pump chamber cavity  482  and defines the irrigation inlet port  506  thereto. The cassette body front wall  464 , in its portion  510  below the elbow passage  504 , extends downward and bends rearward in reduced cross section to follow the shape of the pump chamber front face  475  and fillet  479 . Immediately below the pump chamber  470 , and immediately forward of the fillet  479 , the bottom portion  512  of the cassette body front wall  464  extends downward to the pump chamber bottom wall  460 .  
         [0097]     In the preferred embodiment shown, a plurality of closely laterally spaced, upstanding fins  516  extend forward from the cassette body front wall  464 . The forward edges  517  of the fins  516  preferably follow a shallow S-curve which in turn generally follows the profile, seen in cross section in  FIG. 23 , of the irrigation liquid inlet recess  502  and elbow passage  504  and then drops down substantially vertically to the level of the cassette body bottom wall  460 . As seen from above and below, ( FIGS. 22 and 26 ), the forward edges  517  of the fins  516  collectively lie along a shallow, convexly rounded curve. The fins  516  collectively rigidify the front wall  464  of the cassette body, as well as providing a graceful decorative appearance.  
         [0098]     A buttress  520  ( FIGS. 23A, 25  and  26 ) is visible looking forward through the open rear end of the pump cavity  482 . The buttress  520  extends upward from the bottom of the cavity and rearward from the front end face  475  of the pump chamber  470  along the rightward (in  FIG. 25 ) side of the front inner peripheral surface  474  substantially to the level of the central length axis of the pump chamber  470 . The buttress  520  extends rearwardly most of the axial length of the pump chamber rear inner peripheral surface but is spaced forwardly somewhat from the rear facing annular step  472 . As seen from the front, in  FIGS. 23A and 25 , the laterally inboard face  521  of the buttress  520  is rounded in a gradual S-curve, for least interference with rotational irrigation liquid flow within the pump chamber  470 , concavely from the bottom right portion of the front inner peripheral surface  474  upwardly and rightwardly convexly toward the rightward portion of the wall  477  substantially at the height of the longitudinal central axis of the cavity  482 . As seen in  FIG. 25 , an irrigation liquid outlet passage  523  extends down through the top of the buttress  520  substantially flush with the front inner peripheral surface  474  of the pump cavity  482 . A substantially circular cylindrical recess  525  opens downward through the bottom wall  460  of the cassette body  450  and joins the bottom of the outlet passage  523  at a downward facing generally annular step  526 . As seen in  FIG. 25 , if may be convenient to slightly offset the axis of the passage  523  and recess  525 . As seen in  FIGS. 1 and 21 , the irrigation liquid and outlet recesses  502  and  525  are configured to fixedly and sealingly receive the adjacent ends of the irrigation inflow and outlet tubes  44  and  46  in a generally conventional manner, with the ends of such tubes bottoming against the steps  505  ( FIG. 23 ) and  526  ( FIG. 25 ) to flow irrigation liquid into, and out of, the pump chamber cavity  482 . It will be understood that in  FIG. 25 , pumped liquid flow will be clockwise for best flow past the buttress  520  and out through the outlet passage  523 .  
         [0099]     As schematically indicated in  FIG. 23 , a conventional annular seal, preferably a conventional O-ring  530  is sized to seat coaxially in the pump cavity  482  against the forward facing annular step  472  and the rearward inner peripheral surface  477 , for purposes appearing hereinafter. A notch  528  ( FIG. 22 ) opens through the cassette body bottom wall  460  and into the recess  525  for admitting the cable  64  ( FIG. 1 ) into the interior of the cassette body  450 , more particularly into a wiring chamber  529  ( FIGS. 23 and 23 A) beneath the pump chamber  470  and between laterally opposed ones of the fins  492 .  
         [0100]     The cassette body side walls  461  carry, and here incorporate, laterally opposed, rearwardly extending, generally rectangular, resiliently bendable, leaf-spring-like latch arms  540  ( FIGS. 21, 23A ,  24 , and  26 ) having front ends  542  fixed, preferably integrally, on the side walls  461  adjacent the front wall  464 . The latch arms  540  have elongate top and bottom edges separated from upper and lower parts of the sidewalls  461  by vertically spaced forwardly extending slots  544 . The rear ends of the latch arms  540  carry vertically extended, laterally outwardly protruding, substantially triangular cross section (as seen in  FIG. 26 ) fingers  546 , each having a forwardly facing latch face  547  and a rearwardly and radially outwardly angled camming ramp  548 . The rearward end of each latch arm  540 , defined by its corresponding finger  546 , extends rearwardly partially beyond the adjacent portions of the side walls  461  of the cassette body  450 . Shallow, preferably textured finger/thumb depressions  550  face laterally outward from the latch arms  540  intermediate the front and rear ends thereof to facilitate manually pinching, and thereby bending, the rear portions of the latch arms  540  toward each other.  
         [0101]     Laterally spaced guide pins  583  are fixed to extend rearward from the bottom portion  512  of the cassette body front wall  464  adjacent the lower portion of the pump chamber peripheral wall  471  ( FIGS. 23 and 23 A).  
         [0102]     Turning now to the cassette cover subassembly  451  ( FIGS. 21 and 27 - 31 ), same comprises a cassette cover  559  including a forward opening generally cup-like body  560  having a substantially closed front wall  562  and a circularly cylindrical peripheral wall  563  extending rearward from the front wall  562 . An annular flange  564  extends radially outward from the front end of the peripheral wall  563 .  
         [0103]     The exterior surface  570  of the peripheral wall  563  is substantially cylindrical, except for a front facing annular step  571  adjacent the front end of the body  560  ( FIG. 31 ) leading to a reduced diameter, substantially cylindrical boss  572 .  
         [0104]     A cylindrical stub  576  ( FIG. 31 ) protrudes coaxially rearwardly from the front wall  562  to approximately half the depth of the rear opening interior chamber  577  of the cup-like body  560 . The inner peripheral surface  578  of the peripheral wall  563  is tapered in a rearwardly divergent manner at an angle A 3  substantially equal to the angle A 2  ( FIG. 11 ) of the exterior annular surface  109  of the tubular shell  100 . The inner peripheral surface  578  is annularly rounded at its rear end to form a bell mouth  588 .  
         [0105]     Evenly circumferentially spaced, stiffening webs  580  ( FIGS. 29-31 ), here four in number, extend radially from the stub  576  outward to the body peripheral wall  563  and rearwardly from the body front wall  562  nearly to the rear end of the stub  576 . The stub  576  includes a central through bore  584  coaxial with the stub  576  and at the cup-like body peripheral wall  563 . A coaxial cylindrical recess  585  opens rearward from the central bore  584 , toward the open rear end of the cup-like body  560 .  
         [0106]     The radially outwardly extending flange  564  ( FIGS. 29 and 30 ) has a convexly rounded top edge  590 , laterally spaced upstanding side edges  591  and a laterally extending bottom edge  592 . Shallow, generally rectangular, laterally outward opening, vertically elongate, notches  595  ( FIGS. 30 and 31 ) are formed in the upstanding side edges  591  at the ends of the top edge  590  and have upper portions flanking the central length axis of the cylindrical stub  576 .  
         [0107]     A recess  600  ( FIGS. 28 and 31 ), here of generally circular shape, opens rearwardly from the flange  564 , here below the peripheral wall  563  of the cup-like body  560 , and fixedly houses a shallow, cylindrical, substantially puck-like permanent magnet  601 . The rear wall  603  of the recess  600  is sufficiently thin (e.g. 0.050 inch or so) that the magnetic field of the magnet  601  extends, with only minor reduction, rearward from the flange  564 . The magnet  601  and sensor  136  act as the system-on switch as hereafter discussed.  
         [0108]     A pair of hollow, preferably cylindrical, tubular projections  608  ( FIGS. 28 and 31 ) extend forwardly from the front face of the flange  564  in close spaced proximity beneath the peripheral wall  563  of the cup-like body  560 , and in laterally spaced flanking relation with the recess  600 .  
         [0109]     Generally rectilinear, box-like bosses  612  protrude slightly forwardly from the lower corner portions of the flange  564 , are generally vertically centered on and wide spaced laterally on opposite sides of the magnet  601 , and have upper portions more closely spaced upward from and flanking the tubular protrusions  608 . The box-like bosses  612  open rearwardly from the flange  564 , to form respective rearward opening, generally rectilinear wells  613  ( FIG. 27 ). Horizontally elongate, generally rectangular slots  614  (FIG.  28 ) open through the vertical midportion of the otherwise closed front end wall  650  of each of the bosses  612 .  
         [0110]     Electrically conductive, resilient contacts  620  ( FIGS. 29 and 29 A) of generally arrow-head profile, each comprise a generally keyhole shaped central opening  621  having a widened rear portion and narrowed front portion. The contact  620  has a relatively wide, convexly rounded rear portion, and tapers to a narrowed front portion  625 . The contact  620  has oppositely facing outward opening grooves  628  immediately behind the narrowed front portion  625 , to the immediate rear of which lips  630  angle forwardly and oppositely outwardly. The resilient, rubber-like material of the contacts  620  enables same to flex but is also electrically conductive, to enable it to conduct electrical current, by reason of incorporated contiguous conductive particulate matter not shown. The contact  620  is conveniently formed by extrusion followed by cutting into desired length segments, as will be clear from  FIG. 29 . While the contact  620  may be formed of various materials having the characteristics above mentioned, one such material is a rubber material loaded with nickel/graphite so as to be conductive, and available from Laird Technologies, located at San Jose, Calif.  
         [0111]     The contacts  620  are installed in the flange  564  of the cassette cover  559 , in respective ones of the wells  613 . More particularly, the narrowed front portion  625  of each contact  620  is inserted forwardly into its corresponding well  613  and snap fitted through the corresponding slot  614  in the front end wall  615  of the corresponding boss  612 , such that the top and bottom edges of the slot  614  are received in the grooves  628  of the contact  620  and retained therein to block rearward escape of the contact  620 . The contact lips  630  lie in the well  613  and resiliently bear against the front end wall  615  of the boss  612  to block further movement of the contact  620  with respect to the boss end wall  615 . The widened rear portion  624  of the contact  620  extends rearwardly slightly beyond the rear face of the flange  564  to resiliently and electrically engage the slightly protruding front head of the pin-like console face plate contact  168 , which aligns therewith, in the assembled  FIG. 2  apparatus.  
         [0112]     A conventional, generally C-section conductive terminal  66  ( FIG. 29, 29A ) is conductively fixed on the adjacent end of each of the insulated wires  65  defining the cable  64 . This concave side of each terminal  66  is pressed fixedly onto the front edge of the right and left horizontal fins  494  of  FIG. 23A . Thus, with each contact  620  in its installed  FIG. 29A  position in its boss  612 , its narrow front portion  625  resiliently and electrically conductively presses against the corresponding conductive terminal  66 , to electrically connect the wires of cable  64  to the resilient contacts  620 .  
         [0113]     A shaft  636  ( FIG. 29 ) is rotatably received in the central through bore  584  and protrudes forwardly and rearwardly therebeyond. The thus exposed front end of the shaft  636  fixedly and coaxially carries a pump impeller  638  ( FIG. 29 ), having a radially extending base  639  and liquid engaging and impelling blades  640 . To the extent described, the impeller  638  may be similar to that disclosed in U.S. Pat. No. 5,484,402 (Attorney&#39;s reference S*E Case 139) assigned to the assignee of the present invention, the disclosure which is incorporated by reference herein. The impeller  638  further includes a radially buttressed, rearward extending spacer hub  641  for bearing rotatably on the front wall  562  ( FIG. 31 ) of the cassette cover  559 .  
         [0114]     The exposed rear portion of the shaft  636  carries, in sequence, an annular seal (preferably an O-ring)  644  for bearing against the rear end of the stub  576  ( FIG. 31 ) in liquid sealing relation, a conventional jamb washer  646  for fixedly retaining the O-ring  644  against the stub  576 , a disk-like coupler adaptor  648 , and a cassette coupler  650 .  
         [0115]     The coupler adaptor  648  comprises (1) a disk  660 , (2) a hub  661  fixedly and coaxially extending rearward from the disk, (3) evenly circumferentially spaced, generally rectangular, outward opening, perimeter notches  664  (here three in number), and (4) forwardly extending pins  666  fixed to the rear face of the disk  660  in evenly circumferentially spaced relation with each other and with the notches  664  and equally spaced between the hub and the peripheral edge of the disk  660 . The disk  660  is washer-like, with a central opening (not shown) to receive the rear end portion of the shaft  636  rearwardly therethrough. The hub is hollow with a central through opening communicating with the central opening of the disk in a coaxial manner and receiving the rearward portion of the shaft  636  therethrough.  
         [0116]     The cassette coupler  650  ( FIGS. 33-33B ) comprises a disk-like base  670  and a rearward extending hub  672 . Equally circumferentially spaced, driven teeth  674  (here three in number) extend rearwardly from the base  670  and beyond the hub  672 . The teeth extend radially outward from the hub substantially to the periphery of the base  670 . The radially outer surfaces  675  of the teeth are rearward extensions of the peripheral edge of the circular disk-like base  670 , and hence may be thought of circumferentially spaced segments of a circular cylinder. The circumferentially spaced sides  677  of each tooth  674  lie in planes extending rearwardly and toward the longitudinal axis of the shaft  636  and hub  672 , as seen in  FIG. 33B , at an angle A 6  preferably in the range 57-63 degrees, here 60 degrees.  
         [0117]     In the embodiments shown, the portions of the tooth sides  677 , immediately adjacent the base  670 , are preferably filleted, as indicated at  678 , into the base  670  to strengthen the connection of the teeth to the base. The free, rear ends of the teeth  674  are pointed in profile, looking radially inward at the center tooth  674  in  FIG. 33 , as defined by rearwardly convergent and upwardly convergent (in  FIG. 33 ), planar ramp, or guide, faces  680  meeting with their rearward edges in a radially extending ridge line  681 . Each tooth  674  has a radially inboard face  684  ( FIG. 33A ) angled rearward and somewhat radially outward from the rear end of the hub  672  at an angle A 5  (for example in a range of 100 to 105 degrees, here about 102 degrees).  
         [0118]     The cassette coupler  650  has a cylindrical, coaxial, forwardly chamfered bore  688  sized to fixedly snugly receive the hub  661  of the coupler adaptor  648  ( FIG. 29 ), as by press fit or other convenient fixed securement. The cassette coupler  650  further includes forward opening, cylindrical, forwardly chamfered drive pin recesses  690  preferably circumferentially centered at the base of each tooth  674 , the pin recesses  690  being sized and located to snugly drivingly receive the pins  666  of the couple adaptor  648  for circumferential driving of the coupler adaptor  648 , shaft  636  and impeller  638  by the cassette coupler  650 .  
         [0119]     The cassette coupler  650  is preferably of a relatively stiff, somewhat resilient, rubber-like material (for example a material available under the trade name SANTOPRENE™ model 201-73, available from Advanced Elastomer Systems located at Akron, Ohio. This material has surface resilience to accommodate some misalignment between the cassette coupler  650  and the motor coupler  158  ( FIG. 9 ), as well as to damp noise of contact therebetween as the motor  144  turns on and off and torque applied by the coupler  158  to the coupler  650  reverses.  
         [0120]     The motor coupler  158  ( FIG. 32 ) is generally similar in appearance to the cassette coupler  650  but differs therefrom in several respects as follows. The motor coupler  158  has teeth  704  which differ in size and shape from the teeth  674  so as to axially and circumferentially drivably receive in the circumferential spaces  703  therebetween the driven teeth  674  of the cassette coupler  650 .  
         [0121]     The angle A 7  defined by the circumferentially oppositely facing side  706  of each tooth  704  is preferably in the range 77 to 81 degrees, here 79 degrees. The sides  706  of a given tooth  704  lie in planes converging toward the hub  708  of the motor coupler  158  and meet on an axial line through the adjacent radially outer portion of the hub  708  and spaced radially outward from the central axis of the hub  708  and motor coupler  158 . The angle A 8  defined circumferentially across the space  703  between adjacent teeth  704  is preferably in the range of 38 to 44 degrees, here 41 degrees, and the planes of the thus spaced tooth sides  706  extend inward past the hub  708 , here substantially to the radially inboard end of the ridge  710  of the diametrically opposed tooth  704 . In any event, the radially outer portion  707  of each tooth  704  of the motor coupler  158  fits snugly circumferentially between the radially outer portions of two teeth  674  of the cassette coupler  650 , and vice versa, as indicated in dotted lines at  674  in  FIG. 32A and 704  in  FIG. 33B , to transmit torque at the outer perimeter portions of the couplers.  
         [0122]     The motor coupler  158  has a rearward (downward in  FIG. 32 ) opening, blind bore  712  for receiving and fixedly (by any convenient means not shown) engaging the front end of the motor shaft  146  ( FIG. 9 ). The motor coupler  158  is sized to fit rotatably within the forward facing recess  107  ( FIG. 11 ) of the front chassis  80  and is preferably of a diameter substantially identical to that of the cassette coupler  650 . The motor coupler  158  ( FIG. 32 ) lacks the pin recesses  690  of the cassette coupler  650  and is preferably of a hard, rigid material, such as, for example, anodized aluminum. Otherwise the motor coupler  158  is generally similar to the cassette coupler  650  above described in more detail.  
         [0123]     The major parts of the apparatus are of complex form and are conveniently and economically of molded plastics materials. See for example, parts  180 ,  158 ,  80  and  194  ( FIG. 9 ), parts  400 ,  250 ,  300  and  385  ( FIG. 15 ) and  650 ,  451 ,  450 , and  638  ( FIG. 21 ), and part  648  ( FIG. 29 ).  
         [0124]     The above described control  180  ( FIG. 9 ) and power supply  384  ( FIG. 15 ) may be conventional and of any convenient type. It is preferred that the circuitry of the apparatus be as block diagramed in  FIG. 34 , with a control  180  in the form of a suitably programmed microcontroller operating as described hereafter. However, it is also contemplated that the fundamental operation of the apparatus could be controlled manually as hereafter discussed with respect to  FIG. 34A .  
         [0125]     Thus, the  FIG. 34  and  34 A embodiments provide for temporary connection of the AC source AC through the power cord  420  to the power supply unit  384  to charge the batteries  330  (in  FIG. 34  by a path through the microcontroller  180 ). The battery unit  330  provides electrical operating power to the control  180 . The motor on/off switch SW of the handpiece  50 , the system turn on switch defined by the contacts  136  and  601 , the battery check switch  201  and the flow rate control switch  198  are manually responsive and provide controlled inputs to the control  180  which provides the outputs to the flow rate display  199  and battery status indicator  200 , as well as having a monitorable electric current output path to the motor  401 .  
       Assembly  
       [0126]     Assuming the console  14  to be assembled in the manner above discussed and the cassette unit  16  to be assembled in the manner above discussed, including the handpiece  50  and the tubes variously indicated at  44 ,  42 ,  46  and  60 , the power cord  420  is connected to the conventional AC source AC (e.g. a conventional 120 VAC wall socket) and to the power entry module  400  ( FIGS. 1 and 15 ) in the back of the rear console assembly  71  of the console  14 , to charge the battery pack  330 . The battery indicator  200  can be connected to indicate battery condition by reason of (1) the system on switch  136 ,  601  connecting the battery pack  330  to the power supply  384  or (2) upon activation of the battery check switch  201  or (3) during charging in the  FIG. 34  embodiment, or more simply in the (2) and (3) conditions in the simplified  FIG. 34A  embodiment.  
         [0127]     With the battery pack  330  fully charged, power cord  420  may be disconnected and the surgical irrigation apparatus  12  ( FIG. 1 ) is ready for use.  
         [0128]     To ready the apparatus for surgery, the console  14  is fixed to a support (e.g. the  FIG. 1  pole  22 ) as shown in  FIG. 3 , namely by pocketing the pole  22  against the friction pads  364  ( FIG. 20 ) of the clamp base  351  and tightening the clamp screw  360  ( FIGS. 3 and 5 ) to fix the pole  22  against the clamp base  351  at a convenient height on the pole  22 .  
         [0129]     The cassette unit  16  is prepared as schematically indicated in  FIG. 1 , namely with irrigation inlet tubes  42  and  44  running to the inlet of the pump cassette  40  and irrigation outlet tube  46  and cable  64  running from the pump cassette to the handpiece  50  and with the handpiece connected by the suction tube  60  to a suction container SC in turn connected to a suitable suction terminal ST and with a tip  58  of desired type fixed to the front end of the handpiece  50 . The arrangement of the handpiece  50  tubes  46  and  60 , cable  64  and tip  58  is preferably similar to that disclosed in the prior U.S. patents above mentioned and assigned to the assignee of the present invention.  
         [0130]     With an irrigation liquid bag, or bags,  25 , on the arms  23  ( FIG. 1 ) on the pole  22 , and spaced above the console  14 , a conventional inlet fitting, sometimes referred to as a spike,  30  ( FIG. 21 ), with its usual protective cover  31  removed and its bottom portion  32  connected to the upper end of the tube  42  or  44  ( FIG. 1 ), is inserted upward into the outlet fitting  27  of a corresponding irrigation liquid bag  25 .  
         [0131]     The pump cassette  40  can depend from its thus connected tube  42  adjacent the console  14  until it is to be used by the surgical team. At that point a surgical team member grips the pump cassette  40  from the front (seen in  FIG. 2 ) thereof and pushes the rear portion of the cassette  40  into the front opening cassette main recess  96  ( FIG. 9 ). Continuing, the front ends  542  ( FIG. 21 ) of the cassette latch arms  540  enter the slots  103  ( FIGS. 2D, 7  and  10 ) on opposite sides of the back wall  98  of the cassette receiving recess  96  of the front console chassis  80 , the feet  546  resiliently engaging and sliding rearward along the upward walls of the slots  103  and finally snapping resiliently laterally outward so as to be trapped snugly behind the cassette mounting bezels  102  ( FIGS. 2D and 10 ). At the same time, the rear portion of the assembled cassette body  450  and cassette cover subassembly  451  ( FIG. 21 ) enters rearwardly into the open front of the cassette receiving recess  96  ( FIG. 11 ) and into the fully installed position of  FIGS. 2B and 2D . In this position, the forwardly convergently tapering, external annular surface  109  of the front console chassis  80  has snugly telescopingly entered into surrounded, contacting relation with the rearwardly divergently tapered annular inner-peripheral surface  578  of the cassette cover subassembly  451  ( FIGS. 2B and 29A ), thereby precisely coaxially locating the motor shaft  146  and impellor shaft  636 . This brings the motor coupler  158  and cassette coupler  650  ( FIGS. 32 and 33 ) coaxially together, the ramps  709  and  680  thereof slidingly, cammingly engaging to interdigitate the teeth of each coupler  158  and  650  in the between-tooth spaces of the other, in circumferentially snug, rotatably driving engagement.  
         [0132]     Further, such pushing of the pump cassette  40  into the front recess portion of the front chassis  80 , places the rear cassette flange  564  ( FIGS. 2B and 21 ) into snug engagement with the front face of the back wall  98  ( FIGS. 2B and 11 ) of the boss  99 .  
         [0133]     This places the magnet  601  ( FIG. 2B ) into coaxially opposed activating relation with the magnetic proximity sensor  136  and brings the resilient contacts  620  ( FIGS. 2C and 29A ), which in turn are electrically connected to the insulated wires of the cable  64  leading to the switch SW on the handpiece  50 , into resilient contact with and electrically conducting relation with the pin-like console face plate contacts  168  of the front console assembly  70 .  
         [0134]     With the cassette unit  16  fixed to the front of the console  14 , as above discussed with respect to  FIGS. 2A-2D , the batteries  330  energize the flow rate display  199  and battery indicator  200 , directly as seen in  FIG. 34A  or through the microcontroller  180  as seen in  FIG. 34 .  
         [0135]     Thereafter, closing the switch SW on the handpiece  50  ( FIG. 1 ), here by pushing the irrigation trumpet valve push button  54 , completes the electrical path through the wires of the cable  64  ( FIGS. 1 and 2 ) and thence through the terminals  66  on the cable wires  65  ( FIG. 29A ) to the resilient electrical contacts  620  in the flange  564  of the cassette cover  559  ( FIGS. 2C, 21 ,  29 , and  29 A), and hence through the pin-like console face plate contacts  168  (see also  FIGS. 4, 7 ,  8 ,  9 , and  12 ) to complete the electric current path to the motor  144  directly as seen in  FIG. 34A  or through the microcontroller  180  as in  FIG. 34 . This turns on the motor  144  which rotates the couplers  158  and  650  ( FIGS. 2B, 2D ,  7 ,  9 ,  21 ,  27 ,  29 A,  32  and  33 ) and thereby the pump impellor  638  ( FIGS. 2B, 2D ,  21 ,  28 , and  29 ). The impellor  638  thereby pumps the irrigation liquid, incoming through the irrigation liquid inlet recess  502  ( FIG. 23 ) and elbow passage  504  and inlet port  506 , clockwise as seen in  FIG. 25  and thence down through the irrigation liquid outlet passage  523  in the buttress  520  and into the outlet tube  46  ( FIG. 1 ) received in the recess  525  of  FIG. 25  to the handpiece  50 . Pumped liquid from the tube  46  thus passes through the handpiece irrigation valve opened by depression of the valve push button  54 , as above described, to flow irrigation liquid through the handpiece tip  58  to the surgical site SS of the patient P.  
         [0136]     In the foregoing, with the inlet tube  42  (directly or through the Y tube  44 ) spiked into the irrigation liquid bag  25  ( FIG. 1 ) the cassette  40  hangs directly in front of the console  14 , and specifically in front of the cassette recess  96 . Thus, a surgical team member need only push the cassette rearward, in a single movement, to insert the cassette into the console. This “single-movement” insertion is further made possible by the horizontal orientation of the pump impellor shaft  636  ( FIG. 2B ) and motor shaft  146 .  
         [0137]     Further, the matching conical tapers of the walls  109  and  578  ( FIG. 2B ) of the console  14  and cassette  40 , surrounding the engaged couplers  158  and  650 , and the reception of the console&#39;s conical protrusion (or substantially tubular shell)  100  in the corresponding tapered conical hole (defined by the inner-peripheral surface  578  of an interior chamber  577  of the cup-like body  560  of the cassette cover  559 ) ( FIGS. 29 and 31 ), properly aligns the cassette in the console and allows for as tight a fit as possible therebetween for efficient power transmission from the console to the cassette. This conical fit feature allows the cassette to easily slide into position until, when fully in position, tight tolerances ensure proper supporting fit of cassette on console and coaxial alignment of the motor and impellor shafts.  
         [0138]     Further, it is the installation of the cassette  40  on the console  14  that causes the magnet  601  ( FIG. 2B ) to actuate the sensor  136  (preferably a conventional reed switch) to automatically connect the battery pack  330  to the control  180  ( FIGS. 34 and 34 A) to automatically “power up” the console  14 . This saves the user the usual additional step of separately turning on the system by pushing a start button or the like, as in conventional systems.  
         [0139]     Further, providing one of the couplers  158  and  650 , preferably the cassette coupler  650 , of a flexible rubber, or rubber-like plastic, material enables efficient power transmission from the motor to the impellor despite possible misalignment of the motor and impeller shafts.  
         [0140]     Further, the provision of electrical connection between the cassette and console in the form of the rubber, or rubber-like plastic, electro-conductive contacts  620  ( FIGS. 2C, 21 ,  29 , and  29 A), set into the flange  564  of the cassette cover  559 , provides a clean looking and flexible method for transmitting the electrical signal (switch SW closure) from the handpiece  50  through the cassette  40  to the console  14 . The resilience of the contacts  620  establishes reliable and full electrical contact with the pin-like contacts  168  of the console (as schematically indicated in  FIG. 29A ) despite variation in the clearance between the cassette flange  564  and the back wall  98  of the recess  96  of the console  14 .  
         [0141]     Further, electrically powering the console  14  with a battery (onboard battery pack  330 ) reduces clutter in the surgical operating room by eliminating the usual AC power cord which typically powers conventional irrigation supply consoles. Further, the battery pack  330  is sized to-provide operating power for a number of typical operations (e.g. 30). Moreover, construction of the battery pack  330  from rechargeable cells and inclusion of means in the console  14  to recharge the battery pack  330  (usually outside the surgical operating theater between surgical operations) essentially eliminates the time and effort required to change batteries over the life of, or at least infrequently during the life of, the console  14 , for significant labor cost savings and eliminates frequent battery cell purchases.  
         [0142]     Further, the buttress  520  ( FIG. 25 ) protruding into the volute (i.e. the front inner peripheral surface  474 ) of the pump chamber  470 , raises the chamber outlet to the irrigation liquid outlet passage  523  vertically, substantially to the horizontal diametral plane of the pump chamber  470 . Thus, initial gravity flow, from the irrigation liquid supply bag  25  through the tube  42  ( FIG. 1 ) into the pump chamber  470 , quickly fills the pump chamber over half full, namely up to the level of the impeller axis and reliably primes the pump, yet allows the cassette body  450  to be molded as a single piece. Applicants found that locating the irrigation liquid outlet lower in the pump chamber interfered with reliable priming.  
         [0143]     Preferably, the mechanical self priming and mentioned method are used together to ensure proper priming.  
         [0144]     In addition to this mechanical self priming of the pump, an embodiment of the invention provides a method for checking and assuring priming of the pump, which method can be carried out manually, using the  FIG. 34A  embodiment, or conveniently, by appropriate programming of the  FIG. 34  microcontroller  180 , such method being set forth in the  FIG. 35  flowchart.  
         [0145]     Attention is directed to the priming flowchart of  FIG. 35 . As above indicated, insertion of the cassette  16  into the console  14  closes the contacts  136 ,  601  and  30  automatically turns on the system  10 . The system  10  thus is ready to proceed at the last voltage level set (stored) by the up-down flow rate switch  198 . To turn on the pump motor, the user depresses the irrigation valve button  54  on the handpiece  50 , thereby closing the motor-on switch SW ( FIGS. 34 and 34 A). The microcontroller  180  (or the user in the  FIG. 34A  embodiment by using the up-down flow rates switch  198 ) applies maximum voltage to the pump motor for a predetermined time duration T 1 . If motor current sensed by the  FIG. 34  microcontroller (or seen by the user in the  FIG. 34A  embodiment on the motor current readout MC) is within a desired range, between minimum and maximum, the motor is run by the  FIG. 34  microcontroller at the first mentioned “stored” flow rate voltage level or, in the case of the  FIG. 34A  manual embodiment, by the user resetting the up-down flow rate switch  198 . If motor current sensed by the  FIG. 34  microcontroller (or seen by the user in the  FIG. 34A  embodiment on the monitor current read out MC) is above the desired range, the motor impedance is excessive and an “error” situation exists. On the other hand, if motor current is less than the desired range minimum, the microcontroller of  FIG. 34  (or the user in the  FIG. 34A  system using the up down flow rate switch  198 ) switches the motor voltage low for duration T 2 . Then the maximum voltage is applied to T 1  duration. Next, the motor current is again monitored. If motor current is in the desired range, the motor is run by the  FIG. 34  microcontroller at the first mentioned “stored” flow rate voltage level (or, in the case of the  FIG. 34A  manual embodiment, by the user resetting the up-down flow rate switch  198 .  
         [0146]     After a time T 3 , motor current is checked again to determine if it is less than, greater than, or in the desired range. If greater, the above described error condition exists. If less, the microcontroller of  FIG. 34  (or the user in the  FIG. 34A  embodiment) once again applies high voltage for the T 1  duration and the cycle following the third step of the  FIG. 35  flow chart starts again. If in the desired range, the motor continues to receive the last desired flow rate voltage level, namely per step  5  of the  FIG. 35  flowchart.  
         [0147]     Too high motor current could be caused, for example, by a faulty cassette that does not allow the coupler to rotate properly. On the other hand, too low motor current could be caused, for example, by the emptying of the fluid from the system and the system needs to have the bag changed out.  
         [0148]     The motor current limits differ for the different voltage levels selected by the up-down flow rate switch  109 . In one embodiment, the desired ranges were set as follows:  
         [0149]     (1) switch  198  set low, current range up to 1.95 A;  
         [0150]     (2) switch  198  set medium, current range 1.04 A to 2.93 A; and  
         [0151]     (3) switch  198  set high, current range 1.37 A to 3.91 A.  
         [0152]     Although particular preferred embodiments of the invention have been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.