GB2119450A

GB2119450A - Dental turbine

Info

Publication number: GB2119450A
Application number: GB08302181A
Authority: GB
Inventors: Martinez Jose Maria Martinez
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-04-23
Filing date: 1983-01-26
Publication date: 1983-11-16
Also published as: ES264692U; GB8302181D0; IT8319634A0; IT8320841V0; ES264692Y; DE3302545A1; IT1193675B; FR2525463A1

Abstract

In order to positively locate the bearings 6 in which shaft 7 of an air rotor 4 rotates in the cylindrical housing 1 of a dental turbine, the interior of the housing 1 is provided with stops 9, 10 against which the fixed parts of the bearings 6 are located. The bearings 6 are pressed against the stops 9, 10 by the end covers 8 of the housing 1. <IMAGE>

Description

SPECIFICATION Improved head piece for cross-angles of dental turbines The present invention refers to a head piece for cross-angles of dental turbines, which has been substantially improved in order to enhance its operation and efficiency.

Conventionally, these types of device work by using a stream of air under pressure as a power source. The air flows tangentially over a turbine whose shaft is mounted on the head piece itself through bearings at each end. A drill with which the dental operation is to be performed is connected with the shaft.

Also conventionally, the head pieces have a hollow cylindrical shape, in the interior of which the two bearings and the intervening turbine are freely disposed, these elements remaining secure by means of two end covers corresponding with the bases of the notional cylinder. The covers are in turn provided with central orifices for the passage of the corresponding output drive axle.

In such an arrangement the bearings are mounted in the interior of the head piece so as to have floating characteristics, which gives rise to oscillations in the drills associated with the spindle and to the result that the holes drilled are not the perfect holes desired.

- Because of the problem stated above, the improvements to the head piece which are envisaged centre on providing on the existing internal cylindrical surface a discontinuity-in order to provide a better retention of the bearings. This is obtained by means of the formation on said cylindrical surface of the head piece of two peripheral steps. These steps serve as a stop for the respective bearings, which remain urged against said steps by the covers themselves which complete the head piece. In this way complete immobility of the bearings may be achieved.

These steps may be formed from the actual material of the head piece, by means of an interior projection in the middle zone of said head piece.

Alternatively, they may be formed by means of a supplementary ferrule adapted to the internal surface of said head piece and acting as a distance piece between the two bearings. Another possible solution is that of forming in the internal cylindrical surface of the head piece two peripheral grooves, duly located according to the desired stop position, in which grooves are installed respective washers to establish stops for the bearings.

By virtue of the construction as above described, a head piece is obtained capable of working at speeds of from zero to 500,000 r.p.m.

and at a pressure of 5 Kg/cm2, taking advantage integrally of the air force, whereby stopping of the drill in the course of work is prevented. The height of the head piece can be reduced by two or three millimetres in relation to the dimensions of conventional head pieces, which also provides an important advantage given the specific application of the device. The improved fixing of the bearings results in a reduction of breakdowns, in relation to conventional head pieces, by more than fifty per cent.

Also, as a fundamental characteristic of the present arrangement, the drills associated with the drive shaft undergo no oscillation in the normal course of work, with the result that the holes made with them are better than were obtained heretofore.

The invention will now be further described with reference to the accompanying drawing in which the single figure shows a view in diametral section of a head piece for cross angles of a dental turbine.

It may be seen from this drawing that the head piece is provided, as is conventional, with a cylindrical hollow body 1 which extends radially into the coupling neck 2 of the body of the cross angle. Across the neck 2 is provided a path 3 for the input of air to the turbine 4 and return of same, as well as the channels 5 for lubrication of the bearings 6. The bearings 6 support the drive shaft 7 with respect to the fixed part of the head piece, to which shaft 7 is secured the turbine 4.

As is also conventional the cylindrical hollow interior of the head piece 1 is closed by means of end covers 8 which, preferably, are fixed to the same by means of a screw (not shown).

In the arrangement shown, the continuity of the internal cylindrical surface of the head piece is broken by two peripheral- steps 9, 10 which act as retaining stops for the fixed parts of the bearings 6. In this way the fixed part of each bearing 6 remains pressed between a step 9 or 10 and the respective cover 8.

In this manner it is ensured that the bearings 6 are positively held in the axial direction, which provides a notable potential for good operation of the assembly.

As an alternative to the steps 9 and 10 being formed on the internal surface of the head piece by means of an internal projection, integral with the head piece itself, and is shown in the drawing, the steps 9 and 10 may be formed by a supplementary ferrule, as shown in the drawing in dotted lines and referenced 11, which is located at the middle zone of the internal cylindrical surface of the head piece and which acts as a double stop and distance piece for the bearings 6.

As a further alternative the stops 9 and 10 can be formed by washers which are inserted in peripheral grooves provided on the internal surface of a cylindrical head piece.

With each of these embodiments the bearings are perfectly axially retained, which ensures the best fucntional characteristics alluded to above, characteristics which allow the head piece to be used for a period up to double that of conventional head pieces, and furthermore being adaptable to any type of dental equipment, old or new, by the provision of a corresponding adaptor, in each case.

The materials, shape, size and arrangement of the elements can be varied in such a way as not to bring about a change of the essentials of the invention.

Claims

1. A head piece for cross angles of dental turbines of the type having a hollow, cylindrical housing, in the interior of which is housed a turbine on a shaft which is located in the head piece in bearings, and having end covers which close the openings of said housing, is essentially characterised in that on the cylindrical internal surface of the said -housing are two peripherally extending discontinuities, defining respective projecting stops for the respective ends of said bearings, whereby the fixed part of each of said bearings remains held against a respective one-of said steps by the pressure exerted thereon by the respective cover.

2. A head piece according to claim 1, wherein said discontinuities of the internal cylindrical surface of the housing are obtained by means of .an internal projection,lntegral with the housing itself.

3. A head piece -according-to claim 1 whçrein said stops are provided by means of a ferrule adapted to said internal surface of the head piece and acting as a distance piece and double stop for the bearings.

4. A head piece according to claim 1 wherein said stops are formed by washers which are located in peripheral grooves provided in the internal surface of the housing.

5. A head piece for cross angles of dental turbines substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.