Abstract:
A hydraulically driven vehicle is disclosed which is moved or turned by driving left and right hydraulic transmissions with one engine and driving left and right drive wheels with these hydraulic transmissions. The vehicle includes a gear-shifting mechanism for converting the actions of an operator and transmitting the result to the hydraulic transmissions, which mechanism is comprised of a first swinging member that is swung by a vehicle speed cable, and left and right second swinging members that are placed on the first swinging member, that are swung by left and right steering cables, and that push and pull push-pull rods.

Description:
REFERENCE TO PENDING APPLICATIONS  
       [0001]     This application is a continuation-in-part application claiming priority to U.S. patent application Ser. No. 11/348,199, filed Feb. 6, 2006, entitled Ventilator to Tracheotomy Tube Coupling. 
     
    
     REFERENCE TO MICROFICHE APPENDIX  
       [0002]     This application is not referenced in any microfiche appendix.  
       BACKGROUND OF THE INVENTION  
       [0003]     This invention relates generally to medical equipment and more particularly concerns devices used to connect ventilators to tracheotomy tubes.  
         [0004]     For adult patients, two-piece tracheotomy tubes having inner and outer cannulas are presently in common use. The outer cannula is inserted into the patient&#39;s windpipe and the inner cannula is inserted into or removed from the outer cannula for use or for replacement, cleaning or disinfecting, respectively. The outer cannula of these two-piece devices has a collar on its trailing end which is configured to be positively engaged with a collar on the leading end of the inner cannula. The cannulas cannot be disengaged from each other affirmative release of their positive engagement. The trailing end of the combined cannulas has a tapered tubular extension which plugs into or into which is plugged, depending on the diameter of the tubular extension of the particular tracheotomy tube, the leading end of a flexible connector. The trailing end of the flexible connector is connected to a tube extending from the ventilator or other external equipment. The present tapered tubular extension connection to the ventilator is dependent on mere insertion of a tapered tube into a constant diameter tube in the hope of achieving a snug fit. To assist in making this connection, the flexible connectors have annular flanges with significantly wider diameters than the tubular portions of the connectors so as to facilitate manipulation of the connectors with the thumb and forefinger.  
         [0005]     For children, a smaller, one piece tracheotomy tube is made from a very soft, pliant material. The entire tracheotomy tube must be frequently removed, at least once a week, from the child&#39;s trachea, cleaned and disinfected and reinserted into the trachea. The same flanged flexible connector used with the adult devices is also used with the children&#39;s devices. The tapered tubular extension of the children&#39;s tracheotomy tube is integral with the pliant tracheotomy tube and has a hard plastic outer sleeve which is inserted directly into the flexible connector. An annular flange on the trailing end of the tubular extension of the child&#39;s tracheotomy tube holds the hard plastic sleeve in place on the extension.  
         [0006]     Because of their structural configuration and operational steps, there are some problems inherent in the known one or two piece tracheotomy tubes, in the known flexible connectors and in their combination.  
         [0007]     One set of problems is related to the comfort of the patient. The profile of the flanged flexible connectors, falling generally between the underside of the patient&#39;s chin and the patient&#39;s chest, fosters a breakdown of skin and tissue on the chin or chest, depending on the head movements of the patient. This is especially true for children, their chin-to-chest cavity being comparatively small. This concern is sometimes addressed by after-market removal of all or a portion of the flange, but this solution generally results in a damaged connector, increasing the likelihood of infection-causing secretions and also becomes less secure due to removal of the firm portion of the connector. Also, the manipulation of the flange to connect or disconnect the connector to or from the tubular extension can cause considerable discomfort to the patient, since this often requires the application of manual pressure to the patient&#39;s neck, chin or chest. It is common practice to extend rubber bands from one side of a neck plate on the tracheotomy tube collar to the flexible connector and back to the other side of the neck plate in an effort to hold the flexible connector in place, but the rubber bands are likely either too elastic or too inelastic to properly accomplish this purpose. While a child&#39;s tracheotomy tube is smaller than an adult&#39;s, the available space between the chin and chest is significantly smaller and the flexible connector flange is the same size as used for adults, so the smaller device affords no relief for the connector flange related comfort problems. And, since the child&#39;s tracheotomy tubes are of one piece construction, the force necessary to disconnect the flexible connector may be directly applied to the patient&#39;s neck or windpipe.  
         [0008]     A second set of problems is related directly to the ability, or inability, of the system to accomplish its primary purpose of keeping the patient&#39;s trachea connected to the ventilator. To begin with, tapered connections tend to easily separate in the best of circumstances, there being minimal surface contact between the tapered and constant diameter components. Moreover, the connector and tracheotomy tube parts are always wet and slippery due to the very nature of their application and are not very tightly mated because of the neck pressure problems. The end result is a connection so tenuous that a mere sneeze, cough or turn or tip of the head can cause the connector and the tapered tubular extension to separate, defeating the operation of the system. Even without a sneeze, cough, turn or tip, the flange itself functions as a lever against the chin or chest in response to the patient&#39;s head movements, and the reciprocal levering by the flange will eventually cause the connector and the tubular extension to disconnect.  
         [0009]     A third set of problems concerns the performance of the medical staff as a result of these other problems. The inherent comfort issues result in more pains-taking, time-consuming effort by the staff in an effort to reduce the impact of these discomforts on the patient. And, because of the ease of inadvertent disconnection of the system, the staff unnecessarily spends valuable time monitoring and reconnecting the connectors to the tubular extensions of the tracheotomy tubes.  
         [0010]     It is, therefore, a primary object of this invention to provide an improved tracheotomy tube coupling. Another object of this invention is to provide a tracheotomy tube coupling which reduces a likelihood of associated patient discomfort. It is also an object of this invention to provide a tracheotomy tube coupling which is more suitably profiled for positioning between a patient&#39;s chin and chest. Still another object of this invention is to provide a tracheotomy tube coupling which is profiled to reduce a likelihood of skin or tissue breakdown on a patient&#39;s chin and chest. A further object of this invention is to provide a tracheotomy tube coupling which simplifies manipulation of the coupling in relation to the patient. Yet another object of this invention to provide a tracheotomy tube coupling which reduces a likelihood of exertion of discomforting pressure on the chin, neck, chest or windpipe of a patient during connection or disconnection of the coupling from the tracheotomy tube. An additional object of this invention is to provide a tracheotomy tube coupling which makes inadvertent disconnection of the tracheotomy tube from the connected medical equipment less likely. Another object of this invention is to provide a tracheotomy tube coupling which does not rely on tapered to constant diameter connections to maintain connection between the tracheotomy tube and its related equipment. It is also an object of this invention to provide a tracheotomy tube coupling which is profiled to reduce a likelihood that the coupling will operate as a self-disconnecting lever. Still another object of this invention to provide a tracheotomy tube coupling which can be easily connected and disconnected from the tracheotomy tube by the medical staff. A further object of this invention is to provide a tracheotomy tube coupling which can reduce the time expended by the medical staff to monitor and maintain the coupling connections. Yet another object of this invention is to provide a tracheotomy tube coupling which facilitates more rapid disassembly and reassembly of associated components from the tracheotomy tube for cleaning and disinfecting purposes.  
       SUMMARY OF THE INVENTION  
       [0011]     In accordance with the invention, a coupling is provided for connecting a ventilator tube to a tracheotomy tube. The ventilator tube has a connector at its leading end and the tracheotomy tube has a tapered tubular extension on its trailing end. The coupling is a preferably expandable, flexible tubular member with a first adapter on its trailing end for connecting its trailing end in a pneumatic flow path to the ventilator tube leading end connector and a second adapter on its leading end for mating its leading end in a pneumatic flow path with the trailing end of the tracheotomy tube. The second adapter has a latching mechanism for engaging the leading end of the coupling to the tracheotomy tube to prevent the leading end of the tubular member from axially displacing from the trailing end of the tracheotomy tube after they have been mated in the pneumatic flow path. An unlatching mechanism is provided for disengaging the latching mechanism from the tracheotomy tube so as to permit the leading end of the tubular member to axially displace from the trailing end of the tracheotomy tube. The unlatching mechanism is operated by non-axial forces so that the coupling can be disengaged from the tracheotomy tube without exertion of excessive axial force on the patient&#39;s neck.  
         [0012]     Some known adult tracheotomy tubes have an inner cannula inserted into a trailing end of an outer cannula with the tubular extension on the trailing end of the inner cannula. For such tracheotomy tubes, the coupling tubular member has a first means on its leading end for mating the tubular member in the pneumatic flow path with the tubular extension of the inner cannula which is operable by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the outer cannula during mating to prevent the leading end of the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the inner cannula for disengaging the engaging means from the outer cannula by application of force to the mating means in other than the generally axial direction to permit the leading end of the tubular member to axially displace from the tubular extension of the inner cannula. Typically, the trailing end of the outer cannula has opposed annular flanges and the engaging means consists of opposed means for resiliently snapping over the flanges. The disengaging means consists of means on the inner cannula for spreading the opposed flanges during rotational motion of the mating means about a longitudinal axis of the tubular member.  
         [0013]     Other known adult tracheotomy tubes have an inner cannula inserted into a trailing end of an outer cannula with the tubular extension on the trailing end of the inner cannula. For such tracheotomy tubes, the coupling tubular member has a first means on a leading end of the tubular member for mating the tubular member in the pneumatic flow path with the tubular extension of the outer cannula by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the outer cannula during mating to prevent the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the outer cannula which is operable by application of force on the mating means in a direction other than the generally axial direction for disengaging the engaging means from the outer cannula to permit the tubular member to axially displace from the tubular extension of the outer cannula. Typically, the trailing end of the outer cannula has annularly opposed flat notches. The disengaging means consists of means on the outer cannula for spreading the opposed flanges during rotational motion of the mating means about a longitudinal axis of the tubular member.  
         [0014]     Known child tracheotomy tubes have a tubular extension on their trailing end. For such tracheotomy tubes, the coupling tubular member has a first means for mating the leading end of the tubular member in the pneumatic flow path with the tubular extension of the tracheotomy tube by motion of the mating means in a generally axial direction relative to the tubular extension. A second means is provided on the mating means for engaging with the tracheotomy tube to prevent the leading end of the tubular member from axially displacing from the tubular extension after mating. A third means is provided on the mating means which is operable by application of force on the mating means in other than the generally axial direction for disengaging the engaging means from the tracheotomy tube to permit the tubular member to axially displace from the tubular extension of the tracheotomy tube. The mating means consists of a nozzle insertable into the tubular extension. The engaging means consists of a clamshell, the clamshell and the tubular extension having complementary three-dimensional surfaces which prevent axial displacement of the clamshell from the tubular extension gripped therein. Half of the clamshell has diametrically opposite lugs and another half of the clamshell has diametrically opposite fingers which resiliently snap over the lugs when the clamshell is closed. The disengaging means consists of means on the fingers for spreading the fingers in response to inward radial pressure on the spreading means to release the lugs.  
         [0015]     An improved child&#39;s tracheotomy tube has an arcuate soft tube cannula with a neck plate on its trailing end. The neck plate has a passageway aligned with the cannula passageway and an annular ring on its trailing side which extends the passageway. A tubular extension trails from the annular ring to further extend the passageway. Preferably, the tubular extension is formed using a soft inner tube and a hard outer sleeve permanently fused to the soft inner tube. The annular ring has at least one, and preferably three, circumferential sets of at least two displaced serrations in its outer wall. Preferably, the serrations are equally displaced on the circumference, for example two diametrically opposed serrations, with corresponding serrations of each circumferential set being aligned on parallel diameters of the annular ring with the diameters being horizontal in relation to a vertical plane bisecting the arcuate cannula.  
         [0016]     To connect the improved child&#39;s tracheotomy tube to a ventilator tube, the coupling provided has a tubular member adapted at its trailing end for connection in a pneumatic flow path to the ventilator tube leading end connector. The leading end of tubular member is adapted for mating the tubular member in the pneumatic flow path with the tubular extension of the tracheotomy tube by motion of the mating means in a generally axial direction relative to the tubular extension. The leading end of the tubular member is further adapted for engaging with one of the circumferential sets of serrations to prevent the leading end of the tubular member from axially displacing from the tubular extension after mating. The leading end of the tubular member is further adapted to be operable by application of force in other than the generally axial direction for disengaging the leading end of the tubular member from the engaged circumferential set of serrations to permit the leading end of the tubular member to be axially displaced from the tubular extension of the tracheotomy tube. Preferably, the trailing end adaptation of the tubular member is a hard annular ring on its trailing end, the ring having a tubular concentric rearward extension, a sleeve mounted for rotation on the extension and a stop mechanism on the extension for preventing the sleeve from axially displacing from the extension. This sleeve-on-extension configuration of the of the coupling allows rotational forces exerted on the tracheotomy system to be more likely dissipated at the ventilator end rather than the tracheotomy tube end of the system. Preferably, the leading end mating adaptation is a hard sleeve of inner diameter sized to axially receive the tracheotomy tube tubular extension with the trailing face of the tracheotomy tube extension abutting the trailing interior annular wall of the sleeve. Thus, axial motion is required only for initiation of abutting contact, reducing the likelihood of exertion of such axial force as might be required to create a frictionally tight locking fit. Preferably, the leading end engaging adaptation is a circumferential set of at least two fingers resiliently mounted on and oriented forward of the sleeve for seating in one of the circumferential sets of displaced serrations on the tracheotomy tube annular ring when the trailing face of the tracheotomy tube tubular extension abuts the trailing interior annular wall of the sleeve. Thus, the force exerted to engage the components is primarily radial rather than axial or rotational, reducing the likelihood of exertion of excessive axial force on the system. It is also preferred that disengaging adaptation be squeeze plates on the fingers for radially displacing the fingers to release them from the engaged set of serrations in response to radially inward pressure on the squeeze plates. Thus, the force exerted to disengage the components is also primarily radial rather than axial or rotational, reducing the likelihood of exertion of excessive axial force on the system.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]     Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:  
         [0018]      FIG. 1  is a perspective view of a first type of known tracheotomy tube outer cannula;  
         [0019]      FIG. 2  is a perspective view of a first embodiment of an inner cannula for use with the outer cannula of  FIG. 1 ;  
         [0020]      FIG. 3  is a perspective view of a first embodiment of a coupling connected to the inner cannula of  FIG. 2 ;  
         [0021]      FIG. 4  is a side elevation assembly view of the coupling and cannulas of  FIGS. 1-3 ;  
         [0022]      FIG. 5  is a top plan assembly view from the line  5 - 5  of  FIG. 4 ;  
         [0023]      FIG. 6  is a side elevation view of the assembled coupling and cannulas of  FIGS. 1-3 ;  
         [0024]      FIG. 7  is a perspective assembly view of the leading end adapter of the coupling of  FIG. 3  and the outer cannula of  FIG. 1 ;  
         [0025]      FIG. 8  is a side elevation view of the assembled leading end adapter of the coupling of  FIG. 3  and inner cannula of  FIG. 2 ;  
         [0026]      FIG. 9  is a trailing end elevation view of the assembly of  FIG. 8 ;  
         [0027]      FIG. 10  is a top plan view of the assembly of  FIG. 8 ;  
         [0028]      FIG. 11  is a leading end elevation view of the assembly of  FIG. 8 ;  
         [0029]      FIG. 12  is a leading end perspective view of the leading end adapter of the coupling of  FIG. 3 ;  
         [0030]      FIG. 13  is a trailing end perspective view of the leading end adapter of the coupling of  FIG. 3 ;  
         [0031]      FIG. 14  is a side elevation view of the leading end adapter of the coupling of  FIG. 3 ;  
         [0032]      FIG. 15  is a trailing end elevation view of the trailing end adapter of the coupling of  FIG. 3 ;  
         [0033]      FIG. 16  is a top plan view of the leading end adapter of the coupling of  FIG. 1 ;  
         [0034]      FIG. 17  is a leading end perspective view of the inner cannula of  FIG. 2  and leading end adapter of the coupling of  FIG. 3  in an operatively assembled condition;  
         [0035]      FIG. 18  is a leading end perspective view of the inner cannula of  FIG. 2  and leading end adapter of the coupling of  FIG. 3  in a ready-to-disconnect condition;  
         [0036]      FIG. 19  is a perspective assembly view of a second embodiment of the coupling and inner cannula in relationship to a second type of known tracheotomy tube outer cannula;  
         [0037]      FIG. 20  is a top plan assembly view of the coupling and cannulas of  FIG. 19 ;  
         [0038]      FIG. 21  is a trailing end view of the leading end of the coupling of  FIG. 19 ;  
         [0039]      FIG. 22  is a leading end view of the leading end of the coupling of  FIG. 19 ;  
         [0040]      FIG. 23  is a side elevation view of the leading end of the coupling of  FIG. 19 ;  
         [0041]      FIG. 24  is a top plan view of the leading end of the coupling of  FIG. 19 ;  
         [0042]      FIG. 25  is a side elevation assembly view of the cannulas and coupling of  FIG. 19 ;  
         [0043]      FIG. 26  is a side elevation view of the assembled cannulas and coupling of  FIG. 19 ;  
         [0044]      FIG. 27  is a perspective assembly view of a third embodiment of the coupling in relationship to a third type of known tracheotomy tube;  
         [0045]      FIG. 28  is a top plan assembly view of the coupling and tracheotomy tube of  FIG. 27 ;  
         [0046]      FIG. 29  is a leading end perspective view of the coupling of  FIG. 27  in an open condition;  
         [0047]      FIG. 30  is a leading end elevation view of the coupling of  FIG. 27  in the open condition;  
         [0048]      FIG. 31  is a top plan view of the leading end of the coupling of  FIG. 27  in the open condition;  
         [0049]      FIG. 32  is a side elevation view of the leading end of the coupling of  FIG. 27  in the open condition;  
         [0050]      FIG. 33  is a side elevation assembly view of the coupling and tracheotomy tube of  FIG. 27 ;  
         [0051]      FIG. 34  is a side elevation view of the coupling and tracheotomy tube of  FIG. 27  with the leading end of the coupling in the open condition;  
         [0052]      FIG. 35  is a side elevation view of the assembled coupling and tracheotomy tube of  FIG. 27 ; and  
         [0053]      FIG. 36  is a perspective assembly view of an improved child&#39;s tracheotomy tube and associated coupling. 
     
    
       [0054]     While the invention will be described in connection with preferred embodiments thereof, it will be understood that it is not intended to limit the invention to those embodiments or to the details of the construction or arrangement of parts illustrated in the accompanying drawings.  
       DETAILED DESCRIPTION  
       [0055]     Tracheal Inserts: Adult tracheotomy tubes are illustrated in  FIGS. 1-18 , showing a tracheotomy tube with outer and inner cannulas  100  and  130  and a tapered tubular extension  139  on the trailing end of the inner cannula  130  and  FIGS. 19-26 , showing a tracheotomy tube with outer and inner cannulas  200  and  230  and a tapered tubular extension  223  on the trailing end of the outer cannula  200 . A child&#39;s tracheotomy tube is illustrated in  FIGS. 27-35 . A child&#39;s tracheotomy tube has only one cannula which, for purposes of explanation of the invention is identified as an outer cannula  300 .  
         [0056]     All three known outer cannulas  100 ,  200  and  300  are, in some respects, substantially similar, being arced tubes  101 ,  201  or  301  of approximately a quarter circle extending from a leading end  103 ,  203  or  303  to a collar  105 ,  205  or  305  at the trailing end  107 ,  207  or  307  of the arced tube  101 ,  201  or  301 . A cuff  109 ,  209  or  309  on the leading half of the arced tube  101 ,  201  or  301  is inflatable via an air supply line  111 ,  211  or  311 . The arced tube  101 ,  201  or  301  is the tracheal insert portion of the tracheotomy tube and, once inserted, the cuff  109 ,  209  or  309  is inflated to hold and seal the tube  101 ,  201  or  301  in position in the trachea. Each of the outer cannulas  100 ,  200  or  300  has a neck plate  115 ,  215  or  315  which positions the outer cannulas  100 ,  200  or  300  against the patient&#39;s neck and is adapted to maximize its manipulability relative to the collar  105 ,  205  or  305  by connecting hinges  117  or by openings  217  or contours  317  in its body. Each of the neck plates  115 ,  215  or  315  also has openings  119 ,  219  or  319  for connection of an adjustable strap to pass around and secure the neck plates  115 ,  215  or  315  against the patient&#39;s neck. The adult outer cannulas  100  and  200  are comparatively hard and the child&#39;s outer cannula  300  is very soft. From the collars  105 ,  205  and  305  on the trailing ends of the arced tubes  101 ,  201  and  301  toward the trailing ends of the outer cannulas  100 ,  200  and  300 , the configurations of the outer cannulas  100 ,  200  and  300  are quite different.  
         [0057]     Both inner cannulas  130  and  230  are also, in some respects, substantially similar, being arced tubes  131  or  231  of approximately a quarter circle extending from a leading end  133  or  233  to a collar  135  or  235  on a trailing end  137  or  237  of the arced tube  131  or  231 . The inner cannulas  130  and  230  are inserted at their leading ends  131  and  231  into the trailing ends of their outer cannulas  100  and  200  until their trailing ends mate. From the collars  135  and  235  toward the trailing ends of the inner cannulas  130  and  230 , the inner cannulas  130  and  230  are quite different.  
         [0058]     The outer cannulas  100 ,  200  and  300  and their associated known inner cannulas have mechanisms which positively engage them against separation in their mated condition. They all present tapered tubular extensions for connection with known flexible connectors. The connection to known flexible connectors is universally accomplished by mere insertion of a tapered end of a tube into a constant diameter tube. The following illustrated embodiments of the outer cannulas  100 ,  200  and  300  are substantially the same as the known outer cannulas. The illustrated embodiments of the inner cannulas  130  and  230  and the flexible connectors or couplings  160 ,  260  and  360  are substantially different from the known inner cannulas and connectors so as to permit a positive engagement of the outer cannulas with their flexible connectors. However, they have been configured to work with the known outer cannulas  100 ,  200  and  300 . The principles of the invention, however, are fully applicable to the connection of flexible connectors to outer cannulas other than those herein illustrated.  
         [0059]     First Adult Tracheotomy Tube Embodiment: Looking now at  FIGS. 1-18 , the first type of adult tracheotomy tube is illustrated. As best seen in  FIG. 1 , the collar  105  on the outer cannula  100  has an annular ring  121  which is concentric about the trailing end  107  of the outer cannula tube  101  and has top and bottom quarter arcs  123  which extend concentrically on and in a trailing direction from the ring  121 . A concentric groove  125  is also provided in the face of the trailing end  107  of the outer cannula tube  101 .  
         [0060]     Looking at  FIGS. 1-3  and  8 - 11 , the inner cannula  130  applies the principles of the invention to the outer cannula  100 . A soft arced tube  131  extends upwardly and rearwardly from its leading end  133  to a hard collar  135  on its trailing end  137 . The collar  135  tapers outwardly to a wider, concentric, hard, tapered tubular extension  139  which extends in a trailing direction from the collar  135 . The extension  139  tapers toward its trailing end face  141 . The collar  135  has a pair of diametrically opposed latches  143 , as shown appearing at approximately the 2 and 8 o&#39;clock orientations when looking at the trailing end face  141  of the inner cannula  130 . The latches  143  have fingers  145  which extend radially inwardly therefrom for engagement against the trailing face of the annular ring  121  on the trailing end  103  of the outer cannula  100 . The fingers  145  extend in the leading end direction from resiliently flexible supports  147  on the collar  135 . Squeeze plates  149  extend in the trailing end direction from the fingers  145 . The leading faces  151  of the fingers  145  are beveled so that, as the inner cannula  130  is inserted into the outer cannula  100  and the beveled faces contact the annular ring  121 , the supports  147  flex to widen the distance between the fingers  145 . Once the fingers  145  pass over the annular ring  121 , the supports return to their unbiased condition in which the trailing faces of the fingers  145  engage the leading face of the ring  121 , thus locking the inner cannula  130  in place on the outer cannula  100 . The squeeze plates  149  provide suitable surfaces and leverage for the thumb and forefinger to apply pressure to flex the support  147  and spread the fingers  145  so that the fingers  145  can be disengaged from the annular ring  121 . The squeeze plates  149  have alignment indicia such as arrows  153 , as shown diametrically opposed and pointing in the trailing end direction. As best seen in  FIGS. 6, 8 ,  9 ,  11 ,  17  and  18 , the collar  135  also has diametrically opposed rotational and longitudinal ramps  155  and  157  and longitudinal beads  159  for reasons hereinafter explained.  
         [0061]     Looking at  FIGS. 1-16 , the flexible connector  160  for use with the above outer and inner cannulas  100  and  130  has a leading end adapter  161 , best seen in  FIGS. 5, 7  and  12 - 15 . The leading end adapter  161  has a hard outer sleeve  167  with a soft tube liner  169 . The trailing end  171  of the sleeve  167  is of narrower diameter so as to provide a connecting ring  173  for reasons hereinafter explained. The outer sleeve  167  has diametrically opposed posts  175  on its wide circumference at the leading end of the connecting ring  173 . A pair of diametrically opposed resiliently flexible arms  177  extend longitudinally from. the sleeve  167  to radially inwardly extending fingers  179 . The sleeve  167  also has alignment indicia such as arrows  181  pointing in the leading end direction. The flexible connector  160  is in proper rotational orientation for connection to the outer and inner cannulas  100  and  130  when the arrows  153  on the inner cannula  130  are aligned with the arrows  181  on the connector sleeve  167 . As best seen in  FIG. 6 , when the arrows  153  and  181  are aligned, the connector arms  177  can pass under the squeeze plates  149  of the inner cannula latches  143  with the flexible connector fingers  179  at approximately the 4 and 10 o&#39;clock orientations. This positions the connector fingers  179  on the clockwise side of the rotational and longitudinal ramps  155  and  157  when the connector  160  is connected to the outer and inner cannulas  100  and  130 . The leading faces  183  of the connector fingers  179  are beveled so that, as the flexible connector  160  is moved longitudinally into the tapered tubular extension  139  of the inner cannula  130 , the fingers  179  will be spread apart by and slide across the ring  121 , on the outer cannula  100 . Once the fingers  179  pass the ring  121  they resiliently close to secure the flexible connector  160  to the outer cannula  100 . The inner cannula collar  135  is sandwiched between them.  
         [0062]     As best seen in  FIG. 12 , the interior surfaces of the connector arms  177  are provided with longitudinal grooves  185  and the counterclockwise inside edges of the connector arms  177  are provided with longitudinal bevels  187 . To remove the flexible connector  160  from the outer and inner cannulas  100  and  130 , the connector  160  is rotated counterclockwise, as indicated by the rotational arrows  189 , using the thumb and forefinger on the posts  175 . As the connector  160  rotates, the longitudinal bevels  187  on the connector arms  177  ride on the rotational ramps  155  on the inner cannula collar  135  to unlatch the connector fingers  179  from the collar  135 . The rotation is limited to the point of abutment of the inner cannula and connector fingers  145  and  179 , whereupon longitudinal beads  159  on the inner cannula collar  135  and grooves  185  on the connector arms  177  engage to provide an audible click indicating that the connector  160  can be longitudinally displaced and disconnected from the outer and inner cannulas  100  and  130 . As the connector  160  is withdrawn in the trailing direction, the connector fingers  179  ride on the longitudinal ramp  157  of the inner cannula collar  135  to assure that the connector fingers  179  cannot relatch during the process.  
         [0063]     Second Adult Tracheotomy Tube Embodiment: Turning to  FIGS. 19-26 , the other type of adult tracheotomy tube is illustrated. The collar  205  of the outer cannula  200  has a hard annular ring  221  which is concentric about the trailing end  207  of the outer cannula tube  201 . The hard tapered tubular extension  223  of the ring  221  narrows toward the trailing end  225 . Top and bottom approximately quarter notches  227  are provided in the outer circumference of the tapered tubular extension  223  at the trailing end of the ring  221 .  
         [0064]     The inner cannula  230  applies the principles of the invention to the outer cannula  200 . A soft arced tube  231  extends upwardly and rearwardly from its leading end  223  to a concentric collar  235  on its trailing end  237 . A tapered tubular extension  239  extends in a trailing direction from the collar  235  to a trailing end face  241  of an annular ring  243  on the extension  239 . The outside wall of the extension  239  has annular ridges  245  which complement the annular grooves  229  in the inside wall of the outer cannula tapered extension  223  to secure the inner cannula  230  in place in the outer cannula  200 . A pair of vertically aligned studs  247  are provided on the trailing end face  241  of the inner cannula extension  239  for reasons hereinafter explained. A concentric pull ring  249  is hinged  251  to the bottom of the end face  241  of the extensions  239  to facilitate removal of the inner cannula  230  from the outer cannula  200 . An annular outer flange  253  on the midportion of the inner cannula arced tube  231  helps to hold the inner cannula tube  231  concentrically within the outer cannula tube  201 .  
         [0065]     The flexible connector  260  for use with the above outer and inner cannulas  200  and  230  has a leading end adapter  261 , best seen in  FIGS. 21-24 . The leading end adapter  261  has a hard outer sleeve  267  with a soft tube liner  269 . The trailing end  271  of the sleeve  267  is of narrower diameter so as to provide a connecting ring  273  for reasons hereinafter explained. The outer sleeve  267  has a corrugated surface  275  to facilitate manipulation of the flexible connector  260 . Diametrically vertically opposed arms  277  with radially inwardly extending fingers  279  at their leading ends are defined by longitudinal slots  281  in the sleeve  267 . The fingers  279  are contoured to engage in the opposed notches  227  in the outer cannula tapered tubular extension  223 . As best seen in  FIG. 23 , valleys  283  in the inner and outer surfaces of the arms  277  at their trailing ends permit the arms  277  to flex easily. As best seen in  FIGS. 21 and 22 , the leading face of the connecting ring  273  of the leading end adapter  261  has notches  285  which receive the studs  247  on the trailing end face  241  of the inner cannula  230 . The notches  285  extend clockwise from the point of longitudinal insertion of the studs  247  to stops  287 . Counterclockwise rotation of the leading end adapter  261  of the connector  260 , indicated by the rotational arrows  289  on the sleeve  267 , is terminated by the studs  247  striking the stops  287 . At this point, the connector arms  277  will have flexed sufficiently to disengage the connector fingers  279  from the notches  227  in the outer cannula extension  223  so that the connector  260  can be longitudinally withdrawn from the outer and inner cannulas  200  and  230 .  
         [0066]     Child Tracheotomy Tube Embodiment: Turning to  FIGS. 27-35 , the child&#39;s tracheotomy tube is illustrated. As best seen in  FIG. 27 , the collar  305  on the soft tube  301  has a concentric annular ring  321  extending in a trailing direction with a soft tapered extension  323  extending in a trailing direction from the ring  321 . The extension  323  has annular ridges  325  in its circumference and a beveled flange  327  with an annular groove  329  in its trailing end face. A hard sleeve  331  is tapered to concentrically cover the tapered extension  323 . The hard sleeve  331  has a pair of annular flanges  333  at its leading end defining an annular groove  335  therebetween. When the sleeve  331  is mounted on the soft tapered extension  323 , the leading face  337  of the sleeve  331  abuts the trailing end face of the ring  321  on the collar  305  and the trailing end face  341  of the sleeve  331  abuts the leading end face of the beveled flange  327  on the tapered extension  323 , locking the hard sleeve  331  in place on the soft extension  323 .  
         [0067]     Looking at  FIGS. 27-35 , the flexible connector  360  for use with the cannula  300  has a leading end adapter  361 , best seen in  FIGS. 29-32 . The leading end adapter  361  is a clamshell-type grip with bottom and top shells  367  and  369 . The shells  367  and  369  extend from a trailing end face  371  on a trailing connecting ring  373  to a leading connecting ring  375  separated by a narrower body  377 . As best seen in  FIG. 35 , the shells  367  and  369  are defined by a radial cut  379  splitting the top half of the trailing connecting ring  373  and a horizontal diametric cut  381  extending from the radial cut  379  through the leading connecting ring  375 . The shells  367  and  369  are hinged  383  at the top of the radial cut  379 . The leading connecting ring  375  has grooves  385  defining a ridge  387  which will engage in the groove  335  on the leading end of the hard sleeve  331  mounted on the soft tapered tubular extension  323  of the cannula  300 . A tapered nozzle  397  extends in a leading direction from the leading face of the trailing connecting ring  373 . The nozzle  397  has an annular bead  399  on the perimeter of its leading face. A concentric bead  401  is provided on the leading face of the trailing connecting ring  373  around the nozzle  397 . The annular bead  399  on the nozzle  397  abuts the inside wall of the soft tapered tubular extension  323  of the cannula  300  and the concentric bead  401  on the leading connecting ring  375  seats in the groove  329  on the leading face on the beaded flange  327  of the soft tapered tubular extension  323  of the cannula  300  when the soft extension  323  with the hard sleeve  331  are longitudinally inserted into the clamshell of the connector  360 . As best seen in  FIGS. 29-32 , flexibly resilient supports  403  extend radially outwardly from the top shell portion of the body  377  at the diametric cut  381 . Arms  405  extend downwardly, considering the clamshell in the closed condition of  FIG. 35 , from each of the supports  403  to fingers  407  which extend diametrically inwardly from the arms  405 . The fingers  47  have beads  409  on their upper inside edges. The arms  405  also extend upwardly from the supports  403  to corrugated squeeze plates  411  which aid in manually flexing the arms  405  between the thumb and forefinger. To cooperate with the fingers  407 , L-shaped lugs  413  extend upwardly, again considering the clamshell in the closed condition of  FIG. 35 , from the bottom shell portion of the body  377  at the diametric cut  381 . When the top shell  369  is closed on the bottom shell  367 , the fingers  407  snap under the lugs  413  and the beads  409  engage the inside edges of the lugs  413  to assure a stable engagement.  
         [0068]     The above described flexible connector  360  with the clamshell-type leading end adapter  361  accomplishes the objects, aims and advantages of the present invention when used with known outer cannula only or child tracheotomy tubes  300 . Such single cannula tracheotomy tubes  300 , however, have hereinbefore noted deficiencies of their own. In particular, looking at  FIG. 27 , the hard sleeve  331  replaces the manufacturer&#39;s original hard sleeve (not shown) which rotates on the soft extension  323  to allow some freedom of motion of the patient. This configuration focuses the dissipation of rotational forces at the patient end of the tracheotomy system. Moreover, the original and the replacement hard sleeve  331  are locked on the soft extension  323  by the beveled flange  337  and cannot be removed, for cleaning or other reason, without use of a tool and application of force to the tracheotomy tube and, consequently, the patient. Therefore, turning to  FIG. 36 , an improved child&#39;s tracheotomy tube  500  and connector  560  are illustrated which transfer the rotational capability to the connector  560 , so that freedom of motion is maintained and the connector  560  can be disconnected from the tracheotomy tube  500  without applying rotational or longitudinal forces to the tracheotomy tube.  
         [0069]     As seen in  FIG. 36 , the tracheotomy tube  500  is a unitary arrangement of a soft tube  501  formed by a silicone case on a coil of titanium or other non-iron based wire so that the improved tracheotomy tube  500  is compatible with MRI procedures. The soft tube  501  trails to a neck plate  515  with an annular ring  521  on its trailing side. A soft extension  523  trails concentrically from the annular ring  521  to a trailing annular flange  525  having the same diameter as the annular ring  521 . Preferably, the soft extension  523  is covered up to the soft flange  525  by a hard sleeve  531  which is permanently fused to the soft extension  523 . The annular ring  521  has a plurality of circumferential sets of diametrically opposed serrations  543 , preferably and as shown transverse to and straddling the 3 and 9 o&#39;clock diametric plane of the annular ring  521 .  
         [0070]     Continuing to look at  FIG. 36 , the flexible connector  560  has a leading end adapter  561  and a trailing end adapter  563  on the ends of an intermediate tube  565 . The leading end adapter  561  is a hard sleeve with a trailing end annular wall  567 . A pair of diametrically opposed latches  571  have flexible supports  573  which extend radially outwardly from the leading end adapter  561  to forwardly extending arms  575  with inwardly radially extending fingers  577 . As shown, the latch fingers  577  straddle the 3 to 9 o&#39;clock plane so as to be co-operable with the serrations  543  on the tracheotomy tube annular ring  521 . This orientation is preferred so as to reduce the likelihood of the application of pressure by the chin and chest of the patient to the latches  571 . The fingers  577  are engagable in the serrations  543  on the tracheotomy tube annular ring  521  to secure the connector  560  to the tracheotomy tube  500  when the soft flange  525  of the tracheotomy tube extension  523  is in abutment with the trailing end annular wall  567  of the leading end adapter  561 . The walls  545  formed by the annular ring  521  at the ends of the serrations  543  prevent any significant rotation of the leading end adapter  561  in relation to the tracheotomy tube  500 . The plurality of circumferential sets of serrations  543  allows tolerance for the lengths of the leading end adapter  561  and the tracheotomy tube extension  523 . The latches  571  also have rearwardly extending squeeze plates  579  which provide suitable surfaces and leverage for the thumb and forefinger to apply pressure to flex the supports  573  and spread the latch fingers  577  so that the connector  560  can be disengaged from the tracheotomy tube  500  without need for exertion of excessive rotational or axial force on the tracheotomy tube  500 .  
         [0071]     The trailing end adapter  563  has a hard annular ring  581  on its leading end with a tubular concentric rearward extension  583 . The extension  583  has an outer annular groove  585  on its mid-portion, an annular flange  587  on its outer trailing end and a plurality of slots  589  extending axially in its wall from its trailing end toward the groove  585  to provide a plurality of flexible fingers  591  with beveled tips  593 . An O-ring  595  is seated in the groove  585 . A sleeve  597  has a diameter suitable for sliding over the beveled tips  593  of the fingers  591  to radially depress the fingers  591  toward each other and receive the sleeve  597  fully on the extension  583 . The sleeve  597  has an inner annular groove  599 , preferably of cross-section which complements the cross-section of the beveled tips  593  on the trailing end of the sleeve  597 . When the sleeve  597  is fully on the extension  583 , the fingers  591  spread outwardly and the beveled tips  593  engage in the complemental groove  599  to prevent the sleeve  597  from sliding off the extension  583 . The sleeve  597  is free to rotate on the extension  583 , rotation being facilitated by the O-ring  595 . The outer diameter of the sleeve  597  is tapered toward its trailing end to facilitate connection to the ventilator tube (not shown).  
         [0072]     Common Connector Components: Each of the flexible connectors  160 ,  260 ,  360  and  560  has its own unique leading end adapter  161 ,  261 ,  361  and  561  as above described. The trailing end adapters  163 ,  263  and  363  and intermediate tubes  165 ,  265  and  365  for the flexible connectors  160 ,  260  and  360  used with existing tracheotomy tube  100 ,  200  and  300  are substantially the same. Each of these intermediate tubes  165 ,  265  and  365  has a hard annular seat  191 ,  291  and  391  at its leading end. The connecting ring  173 ,  273  and  373  at the trailing end of each leading end adapter  161 ,  261  and  361  fits in and is fixed to the seat  191 ,  291  and  391  of the leading end of the intermediate tube  165 ,  265  and  365 , as by ultrasonic welding. The trailing end adapters  163 ,  263  and  363  have hard tubular extensions  193 ,  293  and  393  with annular flanges  195 ,  295  and  395  to facilitate manipulation of the connectors  160 ,  260  and  360  during attachment to the ventilator. The trailing end adapters  161 ,  261  and  361  are fixed to the trailing ends of their intermediate tubes  165 ,  265  and  365 , also as by ultrasonic welding.  
         [0073]     The intermediate tube  565  used with the improved child&#39;s tracheotomy tube  500  is substantially the same as the intermediate tubes  165 ,  265  and  365  of the other flexible connectors  160 ,  260  and  360 . The leading and trailing end adapters  561  and  563  are different.  
         [0074]     Common Operational Features of the Embodiments: For each of the different tracheotomy tube outer cannulas  100 ,  200  and  300 , the corresponding coupling  160 ,  260  and  360  has a leading end adapter  161 ,  261  and  361  which interlocks with its respective tracheotomy tube outer cannulas  100 ,  200  and  300  preventing them from inadvertently axially displacing from each other. However, non-axial force applied to the unlatching mechanisms disengage the associated adapters  161 ,  261  and  361  from its tracheotomy tube outer cannula  100 ,  200  and  300  so that the coupling  160 ,  260  and  360  can be axially displaced without exertion of excessive axial force on the system and the patient.  
         [0075]     Similarly, for the improved tracheotomy tube  500 , its corresponding coupling  560  has a leading end adapter  561  which interlocks with its tracheotomy tube  500  to prevent them from inadvertently axially displacing from each other. However, non-axial force applied to the unlatching mechanism disengages them so that the coupling  560  can be axially displaced without exertion of excessive axial force on the system and the patient. While the improved tracheotomy tube  500  has been described as being intended for children, this designation is based on the heretofore accepted view that an adult tracheotomy tube has inner and outer cannulas and that a child&#39;s tracheotomy tube has a single cannula. However, the improved cannula  500  can be sized for use by children or adults.  
         [0076]     Thus, it is apparent that there has been provided, in accordance with the invention, a ventilator to tracheotomy tube coupling that fully satisfies the objects, aims and advantages set forth above. While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art and in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit of the appended claims.