CROSS-REFERENCE TO RELATED U.S. APPLICATIONS 
   Not applicable. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT 
   Not applicable. 
   REFERENCE TO AN APPENDIX SUBMITTED ON COMPACT DISC 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to an dental treatment apparatus. More particularly, the present invention relates to dental treatment apparatus having a base and a treatment unit in which the treatment unit includes several treatment instruments and several lines for the supply of water, air and electricity. 
   2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98 
   Dental treatment apparatus having a base and a treatment unit in which the treatment unit has several treatment instruments and several lines for the supply of water, air and electricity is known in the art. However, the dental treatment apparatus of the prior art has a particular drawback. In particular, when the dental treatment apparatus must be serviced or when, as a result of a malfunction, repairs must be made, the entire apparatus is out of use until the repair or servicing activities are completed. 
   It is an object of the present invention to overcome this drawback of the prior art dental treatment apparatus. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention utilizes a connecting apparatus between the base and the treatment unit. This connecting apparatus allows the treatment unit to be disconnected from and connected to the base. Through the use of the apparatus of the present invention, it is possible to incorporate the components of the dental treatment apparatus and to disconnect the treatment apparatus from the base. The connecting apparatus allows these parts to be interchangeable so as to facilitate service and repair. 
   The connecting apparatus of the present invention is formed by first part and a second part that are provided with cooperating connector ports for the supply of water, air and electricity. When the first part and the second part are coupled to each other, the connector ports are connected to each other in such a way that the water lines, air lines and electricity lines from the base to the treatment unit are established. The second part is provided with an opening through which a translatable pin is movable. The translatable pin has an outer end that is fixed to a cable. The translatable pin has an inner flanged member and an outer flanged member at the opposite end from the cable. The inner flanged member is spaced from the outer flanged member in generally parallel relationship. A spring extends between the inner flanged member and a surface of the second part. In this manner, the translatable pin is supported on the second part and allows the translatable pin to be drawn against spring force through the opening in the second part by the cable. 
   The first part is provided with a first opening having a diameter that is greater than the diameter of the outer flanged member. A key slot opens to this first opening. The key slot has a diameter that is smaller than the diameter of the outer flanged member but is larger than the diameter of the translatable pin. As such, when the first part is placed into a proper position, the key slot is placed between the outer flanged member and the inner flanged member and leans against the outer flanged member. When the cable is pulled, the first part is moved towards the second part in such a way that the connector ports are coupled together. 
   The second part is provided with a sleeve in which the translatable pin is movable. The spring is supported on the second part by this sleeve. 
   One of the first and seconds is provided with at least two guide pins and the other of the first and second part is provided with at least two guide holes for receiving the guide pins. In this manner, the first part can be connected to the second part in a fixed orientation. 


   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       FIG. 1  is a perspective view showing the second part. 
       FIG. 2  is a perspective view of the first part. 
       FIG. 3   a  shows a side view of the second part. 
       FIG. 3   b  shows a side view of the first part. 
   


   DETAILED DESCRIPTION OF THE INVENTION 
   As can be seen in the  FIGS. 1 through 3   b , the connecting apparatus of the present invention is formed by a first part  1  and a second part  2  having connector ports  4  and  9  for the supply of water and air. The first part  1  and the second part  2  are further provided with connector ports  5  and  10  for the supply of electricity. When the first part  1  and the second part  2  are coupled to each other, the connector ports  4  and  9  and the connector ports  5  and  10  are connected to each other. In the preferred embodiment of the present invention, the first part  1  is provided with three male connector ports  4  for the supply of water and air. The second part  2  is provided with three female connector ports  9  for the supply of water and air. When the connector ports  4  are connected to the connector ports  9  and when the connector port  5  is connected to the connector port  10 , the lead-through of water, air and electricity from the base to the treatment unit is established. When disconnecting the connections between the connector ports  4  and  9 , the couplings for the water and air supply are automatically closed. As a result, no “leak water” and “leak air” develops. As can be seen in the figures, the electronics are passed through the upper connector ports  5  and  10 . As a result of this, any “post dripping” after the disconnection of the water connector ports will cause no short-circuiting to occur. 
   The second part  2  is provided with a central opening  13  through which a translatable pin  7  is movable. The translatable pin  7  at one outer end  14  is fixed to a cable  20 . The opposite end is provided with an inner flanged member  15  and an outer flanged member  16 . The inner flanged member  15  is in spaced parallel relationship to the outer flanged member  16 . A spring is positioned between the inner flanged member  15  and surface of the second part  2 . As a result, translatable pin  7  is supported on the second part  2 . In this manner, the translatable pin  7  can be drawn against spring force through the opening  13  by the cable  20 . 
   The first part  1  is provided with a central first opening  3  having a diameter such that this can be moved over the outer flanged member  16 . The first opening  3  extends into a key slot  17 . The key slot  17  has a diameter which is smaller than the diameter of the outer flanged member  16  but is larger that the diameter of the translatable pin  7 . When the first part  1  with the key slot  17  is placed in between the inner flanged member  15  and the outer flanged member  16  and leans against the outer flanged member  16 , the pulling of the cable causes the first part  1  to be moved toward the second part  2 . In this manner, the connector ports  4  and  9  and the connector ports  5  and  10  are coupled to each other. 
   In the illustrated embodiment of the present invention, the second part  2  is provided with a guide sleeve  12  in which the translatable pin  7  is movable. The spring  8  is supported on the second part  2  by means of the sleeve  12 . 
   The second part  2  is provided with at least two conical-shaped guide pins  11 . The first part  1  is provided with at least two guide holes  6  for receiving the guide pins  11 . The guide pins  11  have a length such that the outer ends  19  thereof extend beyond the inner flanged member  15  of the translatable pin  7  when the translatable pin  7  is pushed out by the spring  8 . Additionally, the guide slots  18  extend into the guide holes  6  for receiving the outer ends  19  of the guide pins  11 . In this manner, when the parts  1  and  2  are connected to each other and when the translatable pin  7  is moved from the first opening  3  into the key slot  17 , the outer ends  19  of the guide pins  11  are forced by means of the guide slots  18  into the guide holes  6 . 
   Through the construction of the present invention, the female and male connectors for the supply of water, air and electricity will gradually couple with each other. The first part and the second part can be connected to each other in a fixed position. The space between the inner flanged member  15  and the outer flanged member  16  of the translatable pin  7  is only somewhat larger than the thickness of the first part  1 . As such, the first part  1  will fit closely therebetween. In this manner, the displacement or tilting of the second part  2  relative to the first part  1  is prevented. The diameter of the inner flanged member  15  is larger than the diameter of the first opening  3  so as to prevented the first part to be pushed over the inner flanged member  15  during the coupling of the first part  1  to the second part  2 . 
   By virtue of the present invention, it is possible to incorporate the technical portions of the dental treatment apparatus in a treatment unit and to disconnect this treatment unit from the base. As such, it is possible to mount all of the technical parts, in particular those parts that are susceptible to malfunction, as part of an interchangeable unit. When the cable releases the translatable pin  7 , the first part  1  will be pushed away from the second part  2  by the force of the pressure spring  8  and by the springs in the water and air connectors  4  and  9 . The water and air connections automatically are closed after the opening of the coupling. 
   Through the use of these three types of connectors, it is possible to mount all the electronics in the treatment unit. Because of this, it is very simple to interchange the treatment unit in the case of a malfunction or breakdown. 
   The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
Apparatus for dental treatment includes a base, a treatment unit, and a connecting piece. The treatment unit has one or more treatment instruments and one or more lines for the supply of water, air and electricity. The connecting piece is placed in between the base and the treatment unit. The treatment unit can be disconnected from and connected to the base by using the connecting piece.