Abstract:
A filling device for an anesthetic dispenser has a closing element ( 3 ) that can be inserted into the filler neck ( 2 ) and can again be removed from same in a simple manner. A bayonet catch is provided between the closing element ( 3 ) and the filler neck ( 2 ) combined with a ring seal ( 18 ). The a ring seal ( 18 ) can be pressed in an axial direction by axial rotation and has an elastically deformable spring element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2011 010 035.0 filed Feb. 2, 2011, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The present invention pertains to a filling device for an anesthetic dispenser with a filler neck for liquid anesthetic and a closing element that can be attached to the filler neck by means of a threaded connection. 
       BACKGROUND OF THE INVENTION 
       [0003]    A filling device of this type is known from CA 622 821 A. The anesthetic evaporator operating according to the bypass principle has an evaporating chamber, which is filled with liquid anesthetic. Wicks, which dip into the liquid anesthetic, generate a saturated concentration of anesthetic vapor within the evaporating chamber. A filling device for the anesthetic in the form of a filler neck, which is provided with a closing element that can be screwed in, is located on the outside of the evaporating chamber. To replace consumed anesthetic, the closing element is screwed out of the filler neck and anesthetic is filled into the evaporating chamber. The closing element is also used to seal the evaporating chamber in a pressure-sealed and gas-tight manner against the environment after filling. The drawback of the prior-art closing element is that several turns are needed for closing. 
         [0004]    It is also known, as can be determined from EP 348 019 A1, that a sealing ring, which is pressed axially, can be provided between the closing element and the filler neck. Since nearly all elastomeric sealing materials tend to swell under the effect of anesthetic vapor, it is sometimes necessary to apply high torques to loosen the closing element. 
         [0005]    Bayonet catches in anesthetic dispensers are also known, DE 923 500 C, but the sealing problems have not been solved satisfactorily. 
       SUMMARY OF THE INVENTION 
       [0006]    A basic object of the present invention is to improve a filling device of the mentioned type such that the closing element can be inserted into the filler neck and again removed from same in a simple manner. 
         [0007]    According to the invention, a filling device is provided for an anesthetic dispenser. The filling device comprises a filler neck for liquid anesthetic and a closing element that can be attached to the filler neck by means of a threaded connection. The threaded connection is designed as a rotatingly movably actuatable bayonet catch. A ring seal is pressed by the axial rotation. The ring seal has an elastically deformable spring element provided between the closing element and the filler neck. 
         [0008]    The advantage of the device according to the present invention is that the threaded connection between the filler neck and the closing element is designed as a bayonet catch, which is locked or released with a plugging rotary motion. In addition, a ring seal, which can be pressed by the axial rotation of the bayonet catch and which consists of a sealing material and has an elastically deformable spring element, is provided in the connection area of the filler neck and of the closing element. The bayonet catch comprises a bayonet groove at the filler neck and bayonet cams designed correspondingly thereto at the closing element. Polymers, preferably synthetic polymers, for example, those based on carbon, are suitable for use as sealing materials. The bayonet groove is provided with a thread pitch in such a way that the ring seal is pressed axially in the blocked position of the bayonet catch and the closing element is sealed as a result within the filler neck. The axial pressing of the ring seal takes place within the spring deflection preset by the spring element. The spring element consists of metal or an anesthetic-resistant plastic, so that only elastic restoring forces are to be overcome during the axial pressing and swelling effects of the sealing material are of secondary importance. The maximum possible spring stroke can be determined on the basis of the maximum possible angle of rotation of the closing element up to the blocked position and the thread pitch of the bayonet groove and the ring seal is selected to be such that the maximum possible spring stroke is in the elastic deformation range of the ring seal. The bayonet catch combined with the ring seal provided with a spring element has the advantage that the maximum angle of rotation of the closing element for releasing and blocking is limited in such a way that the spring element is deformed only elastically within the ring seal. 
         [0009]    The spring element of the ring seal advantageously has a design that is open on one side with two legs and is, for example, V- or U-shaped. Helical or plate-shaped designs are also suitable for the spring element. A free space, which is reduced during the axial elastic pressing of the ring seal, is present between the legs in the undeformed state of the spring element. The axial force to be applied can be affected by selecting the spring rigidity of the spring element. The closing element is advantageously plugged into the filler neck in a first position and is brought by a rotary motion into a second position, in which the closing element is blocked in the filler neck. 
         [0010]    A means for acoustic signaling at the time of reaching the second position is advantageously provided. This means may be a catch, which is actuated by one of the bayonet cams when the second position is reached and generates by means of a spring mechanism a clicking sound, which indicates the blocked position. The user thus obtains information that the closing element is locked within the filler neck. 
         [0011]    The ring seal is advantageously arranged between a front side of the closing element and a contact surface at the filler neck. 
         [0012]    An exemplary embodiment of the device according to the present invention is shown in the drawings and will be explained in more detail below. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In the drawings: 
           [0014]      FIG. 1  is a perspective view showing a filling device with a closing element positioned above the filler neck according to the invention; 
           [0015]      FIG. 1   a  is a perspective view of the closing element; 
           [0016]      FIG. 1   b  is a perspective view of the filling device; 
           [0017]      FIG. 2  is a sectional view of the filling device according to  FIG. 1 ; 
           [0018]      FIG. 2   a  is a detail “A” according to  FIG. 2 ; 
           [0019]      FIG. 3  is a sectional view corresponding to  FIG. 2  with an acoustic signal generator; and 
           [0020]      FIG. 4  is a top partially sectional view of the filler neck. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]    Referring to the drawings in particular,  FIG. 1  shows a filling device  1  with a filler neck  2  for connecting a reservoir for liquid anesthetic, not shown specifically, and with a closing element  3 , which can be inserted into the filler neck  2 . The filler neck  2  has a cylindrical inner wall  4  with two recesses  5 ,  51  (thread parts) arranged offset by 180 degrees for inserting two bayonet cams  6 ,  61  (complementary thread parts), which have a design corresponding thereto and which are arranged at a cylindrical shaft  7  of the closing element  3 . Bayonet cam  6  is not shown in  FIG. 1 , since it is located opposite the bayonet cam  61 . For greater clarity, the closing element  3  is shown in  FIG. 1  rotated by 90 degrees in relation to the position of the recesses  5 ,  51  of the filler neck  2 . Bayonet grooves  8 ,  81 , which are provided with a thread pitch  9 ,  91  and have dimensions corresponding to those of the bayonet cams  6 ,  61 , are located on the underside of the recesses  5 ,  51 . Only one of the bayonet grooves, namely, bayonet groove  8 , is shown in  FIG. 1  for the sake of greater clarity. The closing element  3  is plugged in a first position  10  in the filler neck  2  by the bayonet cams  6 ,  61  being inserted into the recesses  5 ,  51  and being brought by a quarter turn, during which the bayonet cams  6 ,  61  slide in the bayonet grooves  8 ,  81 , into a second position  11 , in which the closing element  3  is blocked in the filler neck  2 . The closing element  3  has on the top side a toggle-like actuating knob  12  with two opposite grip surfaces  13 , as a result of which a rectangular surface  14  is formed on the top side of the actuating knob  12 . The rectangular surface  14  makes it possible for the user to recognize the angular position of the closing element  3  in relation to the filler neck  2 . When the grip surfaces  13  are located in the drawing plane, this corresponds to the first position  10  of the closing element  3 , in which the latter is plugged into the filler neck  2 . The surface is rotated by 90 degrees in relation to the starting position in the second position  11  of the closing element  3 . The thread pitch  9 ,  91  of the bayonet grooves  8 ,  81  causes the closing element  3  to be screwed into (axial movement) the filler neck  2  during the transition (during rotation of closing element  3 ) from the first position  10  into the second position  11 . Together with the bayonet grooves  8 ,  81  at the filler neck  2 , the bayonet cams  6 ,  61  at the closing element  3  form a bayonet catch  29 . In addition to the filler neck  2 , a sight glass  15 , from which the filling level of the liquid anesthetic in a reservoir, not shown specifically, can be read, is located at the filling device  1 . 
         [0022]      FIG. 1   a  shows as a first addition to  FIG. 1  a perspective view of the closing element  3  with the view towards the bayonet cams  6 ,  61 . 
         [0023]      FIG. 1   b  shows as a second addition to  FIG. 1  a perspective view of the filling device  1  with view from the rear side of the sight glass towards recess  51  and the bayonet groove  81  with the thread pitch  91 . 
         [0024]      FIG. 2  illustrates the filling device  1  according to  FIG. 1  in a longitudinal section. Identical components are designated by the same reference numbers as in  FIG. 1 . A ring seal  18 , which consists of a sealing material  19  with a V-shaped spring element  20  located on the inside, is located between a front side  16  of the closing element  3  and a contact surface  17  on the underside of the filler neck  2 .  FIG. 2   a  shows detail “A” according to  FIG. 2  with an enlarged view of the spring element  20 . When the closing element  3  is rotated from the first position  10  into the second position  11 , the legs  21  of the spring element  20  are pressed against each other and pressed axially due to the thread pitch  9  of the bayonet grooves  8 , as a result of which the closing element  3  is sealed against the filler neck  2  by means of the sealing material  19 . The free space  22  between the legs  21  decreases during the axial pressing of the ring seal  18 . 
         [0025]      FIG. 3  shows a sectional view of the filling device  1  rotated by 180 degrees relative to  FIG. 2 . A contact element in the form of a pin  25 , which is prestressed by a compression spring  24  and is arranged within the bayonet groove  8 , is located in a hole  23 . 
         [0026]      FIG. 4  shows a sectional view of the filling device  1  with a top view of the pin  25  and the bayonet cams  6 ,  61  within the bayonet grooves  8 ,  81 . The bayonet grooves  8 ,  81  have stop faces  26 , with which the bayonet cams  6  are in contact in the second position  11  of the closing element  3 . Step-like depressions  27 , which touch the pin  25  during the transition into the second position  11 , are located on the side of the bayonet cams  6 ,  61  facing away from the stop faces  26 . A “clicking sound,” which indicates to the user that the blocked position has been reached, is generated by the cooperation of the pin  25  prestressed with the compression spring  24  with one of the depressions  27 , which together form an acoustic signal generator  28  that is a preferred signaling means for acoustic signal generation when the second position is reached. 
         [0027]    While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 List of Reference Numbers 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 1 
                 Filling device 
               
               
                 2 
                 Filler neck 
               
               
                 3 
                 Closing element 
               
               
                 4 
                 Inner wall 
               
               
                 5 
                 Recess 
               
               
                 51 
                 Recess 
               
               
                 6 
                 Bayonet cam 
               
               
                 61 
                 Bayonet cam 
               
               
                 7 
                 Straight pin 
               
               
                 8 
                 Bayonet groove 
               
               
                 81 
                 Bayonet groove 
               
               
                 9 
                 Thread pitch 
               
               
                 91 
                 Thread pitch 
               
               
                 10 
                 First position 
               
               
                 11 
                 Second position 
               
               
                 12 
                 Actuating knob 
               
               
                 13 
                 Grip surface 
               
               
                 14 
                 Rectangular surface 
               
               
                 15 
                 Sight glass 
               
               
                 16 
                 Front side 
               
               
                 17 
                 Contact surface 
               
               
                 18 
                 Ring seal 
               
               
                 19 
                 Sealing material 
               
               
                 20 
                 Spring element 
               
               
                 21 
                 Leg 
               
               
                 22 
                 Free space 
               
               
                 23 
                 Hole 
               
               
                 24 
                 Compression spring 
               
               
                 25 
                 Pin 
               
               
                 26 
                 Stop face 
               
               
                 27 
                 Depression 
               
               
                 28 
                 Acoustic signal generator 
               
               
                 29 
                 Bayonet catch