Connector for connecting a dental instrument to a flexible supply tube

Abstract

The invention relates to a connector for the axially rotatable connection of a dental instrument provided with a compressed-air motor or a turbine to a flexible supply tube, the instrument being connected releasably to the connector, which connects the pressure medium inlet and, where appropriate, the coolant inlet of the instrument constantly to the source of coolant or pressure medium.

Description

From the U.S. Pat. No. 3,173,207 a connector of the type specified is known which is connected non-releasably to the connection fitting of the flexible supply tube and therefore forms an integral unit with the supply tube. The known connector, therefore, cannot be made sterile in a sterilising apparatus, which would in principle be the most effective and desirable method of sterilisation. Furthermore, the known connector cannot be connected to the connection fitting of conventional flexible supply tubes, wherein hitherto the instrument has been screwed directly to the connection fitting, in such a manner that after the instrument is connected it has not been possible for the instrument to carry out axial rotational movement relatively to the flexible supply tube.

The invention has as its object to provide a connector of the type mentioned initially which can be sterilised effectively by itself and which the dentist can couple by itself, if desired, to the connection fitting of a flexible supply tube and uncouple therefrom, selectively.

To achieve this object, according to the invention in a connector of the type mentioned initially it is proposed that the supply tube is also connected releasably to the connector.

In this way it is possible for a dentist to obtain and keep in stock a connector as an independent part, so that the dentist can readily connect this connector in a simple manner releasably to the usual supply tube and of course likewise releasably to the instrument, retaining the possibility of rotational movement between instrument and supply tube. This rotatability between instrument and supply tube is important since during operation the flexible orces and this, if the aforesaid rotatability is not possible, results in the dentist only being able to take up the various positions for the instrument for treatment in the patient's mouth with the expenditure of relatively considerable force. After the separation of the connector from the instrument and the flexible supply tube, the connector can be made sterile by itself in a sterilising apparatus.

When treating a patient, it frequently occurs that the dentist requires another tool to be instrument-driven. It is cumbersome and a nuisance more especially during treatment to interchange this tool or possibly the head piece of the instrument with the tool inserted, to have the desired other tool available. In the case of a screwed connection between instrument and connector, unscrewing and screwing-on would take much too long a time, apart from the fact that the fine screwthreads provided for the purpose are very delicate. In order to provide a remedy here, the invention proposes that the connector is connected to the instrument by means of a rapid-action coupling. The dentist then simply needs to operate the rapid-action coupling, whereupon he can separate the entire instrument including tool from the connector and replace it with a new instrument provided with the other tool which he wishes to use.

In order that e.g. in the event of a fracture or other damage to the flexible supply tube, the flexible supply tube does not have to be replaced together with the relatively valuable connector, according to the invention it is proposed that the connector is also connected to the flexible supply tube by means of a rapid-action coupling. In this case it is possible to release the flexible supply tube by means of rapid-action coupling quickly from the connector even during treatment of a patient and replace with a new supply tube after separation from the pressure medium source.

It is advantageous if according to a further proposal of the invention the rapid-action coupling is a snap-action coupling. In this constructional form, the connector has simply to be pushed in the direction towards the end of the instrument or on to the connection fitting of the flexible supply tube until the snap-action coupling engages. The snap-action coupling can be so constructed that it can be separated with a strong or sudden pull in the flexible supply tube. It has been found advantageous if according to a further development of the invention the snap-action coupling has a coupling hook mounted on the connector and engaging under the action of a spring behind an annular collar of the instrument or the connection fitting of the flexible supply tube.

If the coupling hook or hooks is/are mounted directly on the connector, when the instrument is turned relatively to the flexible supply tube the nose of the coupling hook also turns relatively to the annular collar.

Since, during treatment of a patient, the instrument situated in the dentist's hand, the connector and the flexible supply tube are subjected to tension, the nose of the coupling hook slides on the wall of the annular collar. This makes it difficult for the dentist to turn the instrument. Wear phenomena are also unavoidable.

In order to avoid this, according to the invention it is proposed that the bearing of the coupling hook or hooks is/are arranged in each case on a sleeve which is rotatable on the connector but axially non-displaceable. According to this constructional form, the nose of the coupling hook abuts on the wall of the annular collar owing to the aforesaid pulling action without the nose and annular collar and thus the sleeve and instrument or sleeve and connection fitting of the tube rotating relatively to one another. Instead, all that happens now is that the instrument or flexible supply tube rotates relatively to the connector. A rolling contact bearing is provided between connector and sleeve to facilitate this turning movement.

In order to reduce the number of germs in the connector and thus in the instrument as far as possible it is also proposed that the connector in addition to the pressure medium duct which in this case is used for conveying driving air for the compressed-air motor or the turbine, comprises a return air duct and also respective spray air and spray water ducts used for forming the coolant in the instrument, and the ducts comprise transition chambers at the transition regions between the individual parts of the connector which are axially rotatable relatively to one another.

This construction guarantees an air-tight connection between the connector and the instrument and also the flexible supply tube, so that the entry of germs directly into the connector or indirectly by way of the spray is prevented.

It is advantageous, and does not cause any trouble to the dentist, if the connector has an external diameter which is the same size as or approximately the same size as the connection fittings for the instrument and for the flexible supply tube.

Constructional forms of the invention are shown by way of example in the drawings wherein:

FIG. 1 shows in elevation, partly in section, a connector coupled to an instrument and a flexible supply tube,

FIG. 2 shows a sectional view of a connector modified relatively to FIG. 1,

FIG. 3 shows a modified constructional form of a connector in a view on to the end which is connected to the flexible supply tube,

FIG. 4 shows a section taken on the line IV--IV of FIG. 3 and

FIG. 5 shows a section taken on the line V--V of FIG. 3.

1 is a general reference numeral to refer to a dental instrument in the form of an angle handpiece with a shank elbow 2. Arranged on the left-hand end of the shank elbow 2 is an angle handpiece head 3 in which there is situated a compressed-air turbine for driving the tool 4 inserted in the hollow turbine shaft (not visible).

The instrument 1 is coupled in axially rotatable manner to a connector which is given the general reference numeral 5. The connector 5 itself is also coupled to be axially rotatable to the connection fitting 6 of a flexible supply tube indicated generally at 7. The flexible supply tube 7 is used in known manner for supplying the instrument 1 with driving air for the turbine and also with coolant for the spray cooling the tool 4 and the tooth being treated, the spray jets being designated at 8.

In FIG. 1 both the instrument 1 and also the flexible supply tube 7 with connection fitting 6 are connected detachably to the connector 5. These connecting operations are carried out in the case of FIG. 1 with the use of a rapid-action coupling in each case. The rapid-action coupling is constructed as a snap-action coupling and comprises a coupling hook 11 which is mounted on the connector 5 and engages behind an annular collar 10 of the instrument 1 and the connection fitting 6 of the flexible supply tube 7 respectively for this purpose the coupling hook comprises a nose 12. The bearings 13 of the coupling hooks are each arranged on a sleeve 14 which is rotatable on the connector 5 but axially non-displaceable. Rolling contact bearings 15 constructed as ballbearings are provided in each case between the sleeves 14 and connector 5.

For the passage of the various media the connector 5 comprises a central duct 16 for the cooling medium for the spray. In addition, further ducts 17 for the driving air are provided, which open within the instrument 1 into an annular duct 18 so that in any rotated position the driving air can pass from the connector 5 into the instrument 1. From the annular duct 18 a single conduit 19 leads to the head 3. The central duct 16 opens into a conduit 20 likewise arranged centrally in the instrument 1. The driving air and coolant connections at the right-hand side of the connector 5, i.e. between the connector 5 and the flexible supply tube 7 or its connection fitting 6 are constructed in a similar way.

The connector 5 shown in FIG. 2 does not have any rapid-action couplings for connection to the instrument and to the supply tube i.e. to the connection fitting of the said tube. On the contrary, in this case an internal screwthread 21 is provided at the left-hand end of the connector 5 for screwing-in the instrument and at the right-hand end there is provided an external screwthread 22 for the screwing-on of the connection fitting of the flexible supply tube. As in the constructional form shown in FIG. 1, in the constructional form shown in FIG. 2 also when the instrument 1 is handled appropriately by the dentist the connector 5 turns relatively to both the instrument 1 and the flexible supply tube 7, for which purpose two parts 23, 24 are provided in the connector 5. When the instrument 1 is screwed to the connector 5, the part 23 is joined non-rotatably to the instrument 1. The same takes place between the part 24 and the flexible supply tube or its connection fitting 6, so that when the instrument 1 is turned the parts 23 and 24 turn relatively to one another. To reduce friction, rolling contact bearings 25 are provided between the parts 23 and 24 in the form of ball bearings. For the driving air and the coolant, in the case of FIG. 2 passages 26, 27 are provided which are somewhat modified as compared with FIG. 1, with connecting bores or pipes 28, 29, 30, 31 adapted to the connections of known, commercially obtainable instruments and flexible supply tubes. Of course, suitable outlet apertures are also provided for the discharge air coming from the turbine. An outlet gap 32 is provided at the instrument 1 in the case of FIG. 1 and an outlet gap 33 at the connector 5 in the case of FIG. 2.

Sealing rings 34, 35 and 36, 37 respectively are arranged between the parts which are adapted to rotate relatively to one another.

The connections of the connector 5 shown in FIGS. 3 to 5 to the instrument (not shown there) and to the flexible supply tube, which is also not shown, can be effected in the manner shown in FIGS. 1 and 2.

According to FIGS. 3 to 5 the connector 5 comprises, in addition to the pressure medium duct 38 used for conveying driving air for the compressed-air turbine, a return air duct 39 for the return air flowing from the compressed-air motor or turbine, and also a spray air duct 40 and a spray water duct 41 for forming the coolant in the instrument (not shown). The ducts 38, 39, 40, 41 comprise transition chambers 38a, 39a, 40a and 41a at the transition zones between the individual parts 5a, 5b of the connector 5 which are capable of turning relatively to one another about the axis A.

It should also be mentioned that, as in the case of FIGS. 1 and 2, in the illustration shown in FIGS. 4 and 5 the supply tube is connected from the right and the instrument from the left to the connector 5.

Claims

We claim:

1. Connector for the axially rotatable connection of a dental instrument including a compressed-air motor or a turbine to a flexible supply tube, said connector including a rapid-action coupling for detachably connecting the instrument to the connector, which continually connects a pressure medium inlet and a coolant inlet of the instrument to a pressure medium or, respectively, coolant source, said connector including a rapid-action coupling for detachably connecting said flexible supply tube to the connector, each said rapid-action coupling being a snap-action coupling, each said snap-action coupling comprising a coupling hook mounted in the connector, and spring means biasing the hook of one coupling into engagement with annular collar on said instrument and the other hook into engagement with a connection fitting of the flexible supply tube.

2. Connector according to claim 1, comprising bearing means for pivotably supporting the coupling hooks, and sleeve means being rotatably supported on the connector and restrained from axial motion relative thereto, said bearing means being located on said sleeve means.

3. Connector according to claim 2, comprising rolling contact bearings between said sleeve means and said connector.

4. Connector according to claim 3, said instrument and said flexible supply tube being connected to the connector so as to be axially rotatable relative thereto, said compressed-air motor or turbine being driven by pressurized air, said connector including a driving air duct, a return air duct, a spray air duct, and a spray water duct for forming the coolant in the instrument, said ducts each including transition chambers at transition zones between components of the connector adapted to be axially rotated relatively to each other.