Title:
Vacuum Cleaning Tool, Especially Hand-Held Nozzle, for a Vacuum Cleaner
Kind Code:
A1


Abstract:
A vacuum cleaning tool has a housing with a working chamber and a connecting socket for a vacuum hose. A brush roller is arranged in the working chamber. An air turbine is arranged in a turbine chamber between working chamber and connecting socket. The working chamber has a bottom with vacuum air ports through which a vacuum air flow enters the working chamber. The housing has an opening between working chamber and turbine chamber and a discharge opening between turbine chamber and connecting socket. The vacuum air flow passes from the working chamber into the turbine chamber and drives the air turbine and then passes through the discharge opening into the connecting socket. The brush roller acts through the vacuum air ports on a surface to be treated. A bushing on which the air turbine is fixedly mounted is rotatably supported on a support shaft mounted in the housing.



Inventors:
Worwag, Peter (Staad, CH)
Application Number:
11/307510
Publication Date:
08/17/2006
Filing Date:
02/10/2006
Assignee:
DUPRO AG (Romanshorn, CH)
Primary Class:
Other Classes:
15/389
International Classes:
A47L5/10; A47L5/26
View Patent Images:
Related US Applications:



Primary Examiner:
THOMAS, DAVID B
Attorney, Agent or Firm:
GUDRUN E. HUCKETT DRAUDT (WUPPERTAL, DE)
Claims:
What is claimed is:

1. A vacuum cleaning tool for a vacuum cleaning device, the vacuum cleaning tool comprising: a housing having a working chamber at a first end and a connecting socket, adapted to receive a vacuum hose, at a second, opposed end; a brush roller arranged in the working chamber; wherein the housing has a turbine chamber arranged between the working chamber and the connecting socket; an air turbine arranged in the turbine chamber; wherein the working chamber extends transversely to a longitudinal axis of the vacuum cleaning tool; wherein the working chamber has a bottom provided with at least one vacuum air port through which a vacuum air flow enters the working chamber; wherein the housing has a connecting opening between the working chamber and the turbine chamber and a discharge opening between the turbine chamber and the connecting socket, wherein the vacuum air flow passes from the working chamber into the turbine chamber and drives the air turbine, wherein the vacuum air flow passes from the turbine chamber through the discharge opening into the connecting socket; wherein bristles of the brush roller act through the at least one vacuum air port on a surface to be treated; wherein the air turbine has a base member; a support shaft mounted in the housing; a bushing on which the base member of the air turbine is fixedly mounted, wherein the bushing is rotatably supported on the support shaft.

2. The vacuum cleaning tool according to claim 1, further comprising at least one bearing mounted in the housing, wherein the support shaft has at least one axial end supported in the at least one bearing.

3. The vacuum cleaning tool according to claim 1, wherein the support shaft is fixedly secured in the housing.

4. The vacuum cleaning tool according to claim 1, wherein the bushing projects from the base member of the air turbine.

5. The vacuum cleaning tool according to claim 4, further comprising a belt drive having a drive wheel and a belt pulley, wherein the drive wheel is arranged on one end of the bushing and wherein the belt pulley is fixedly connected to the brush roller and is driven by the belt drive by a driving belt guided about the drive wheel and the belt pulley.

6. The vacuum cleaning tool according to claim 5, wherein the drive wheel is fixedly secured on the bushing of the air turbine.

7. The vacuum cleaning tool according to claim 1, wherein the housing comprises a turbine channel that projects into the turbine chamber, wherein the air turbine is positioned, when viewed in an axial direction of the air turbine, with a radial length that is a portion of a diameter of the air turbine partially in the turbine channel.

8. The vacuum cleaning tool according to claim 7, wherein the part of the diameter is more than a radius of the air turbine.

9. The vacuum cleaning tool according to claim 7, wherein the turbine channel ends in the turbine chamber at a spacing from the discharge opening.

10. The vacuum cleaning tool according to claim 7, wherein the turbine channel has lateral walls and wherein the bushing extends through the lateral walls of the turbine channel.

11. The vacuum cleaning tool according to claim 7, wherein a width of the connecting opening matches approximately a width of the turbine channel.

12. The vacuum cleaning tool according to claim 1, wherein the connecting socket has a stepped inner diameter and has a first section and a second section, wherein the first section is located adjacent to an open end opposite the discharge opening and has a first inner diameter, wherein the second section is located adjacent to the turbine chamber and has a second inner diameter, and wherein the first inner diameter is greater than the second inner diameter.

13. The vacuum cleaning tool according to claim 12, wherein the connecting socket comprises a separate socket insert, wherein the first and second sections are provided on the socket insert.

14. The vacuum cleaning tool according to claim 13, wherein the socket insert is secured by a catch in the connecting socket.

15. The vacuum cleaning tool according to claim 13, wherein the socket insert has a circumferentially extending shoulder between the first section and the second section.

16. The vacuum cleaning tool according to claim 13, wherein the inner diameter widens in a flow direction of the vacuum air flow.

17. The vacuum cleaning tool according to claim 1, comprising a belt drive drivingly connecting the air turbine and the brush roller, wherein the working chamber has several of the at least one vacuum air port, wherein at least one of said several vacuum air ports extends from a bottom of the working chamber across a housing edge upwardly into a front end face of the housing, wherein said several vacuum air ports are positioned transversely to the longitudinal axis of the vacuum cleaning tool adjacent to one another, wherein through each of said several vacuum air ports a partial vacuum air flow of the vacuum air flow enters the working chamber and the vacuum air flow combined of the partial vacuum air flows passes into the turbine chamber, and wherein a belt pulley of the belt drive is fixedly connected to a base member of the brush roller and is positioned between ends of the brush roller in an area between two of said several vacuum air ports.

18. The vacuum cleaning tool according to claim 17, wherein said several vacuum air ports are of approximately identical configuration and are spaced at approximately identical spacing from one another.

19. The vacuum cleaning tool according to claim 17, wherein all of said several vacuum air ports extend from the bottom of the working chamber across the housing edge upwardly into the front end face of the housing.

20. The vacuum cleaning tool according to claim 17, wherein a portion of the belt pulley is formed as a monolithic part of the base member of the brush roller.

21. The vacuum cleaning tool according to claim 17, wherein the belt pulley is a monolithic part of the base member of the brush roller.

22. The vacuum cleaning tool according to claim 17, wherein the housing in the area between said two of said several vacuum air ports has a housing web that covers the belt pulley and a driving belt extending about the belt pulley.

23. The vacuum cleaning tool according to claim 22, wherein the housing web and the belt pulley delimit a substantially closed receiving space for the driving belt.

Description:

BACKGROUND OF THE INVENTION

The invention relates to a vacuum cleaning tool for a vacuum cleaning device, in particular, for a vacuum cleaner or the like, comprising a housing having at its front end a working chamber for a brush roller and at the opposed end a connecting socket for attaching a vacuum hose. Between the working chamber and the connecting socket a turbine chamber for an air turbine is arranged in the housing. The working chamber is essentially transversely arranged relative to the longitudinal axis of the vacuum cleaning tool. The bottom of the working chamber is provided with at least one vacuum air port through which a vacuum air flow enters the working chamber. A connecting opening between the working chamber and the turbine chamber is provided through which the vacuum air flow enters the turbine chamber and drives the air turbine. The vacuum air flow passes through the discharge opening into the connecting socket. The air turbine drives the brush roller in rotation, wherein the bristles of the brush roller act through the vacuum air port on the surface to be treated.

Such vacuum cleaning tools are known in various configurations. They are usually designed as floor vacuum nozzles and suitable for cleaning large surface areas. Such floor vacuum nozzles are usable only to a limited extent as hand-held nozzles for cleaning car seats and upholstery or the like. For upholstery cleaning and for special cleaning task, adapted vacuum cleaning tools are offered that are usually configured purely as a vacuum nozzle. A mechanical action on the surface to be cleaned is possible only to a limited extent with such vacuum nozzles.

Other floor vacuum nozzles for a vacuum cleaner have a working chamber for a brush roller provided in a housing; the brush roller is driven in rotation by an air turbine positioned in the housing. The working chamber extends essentially transversely to a longitudinal axis of the floor vacuum nozzle wherein in the bottom of the working chamber at least one vacuum air port is provided through which a vacuum air flow enters the working chamber. By means of a connecting opening provided between the working chamber and the turbine chamber for receiving the air turbine, the vacuum air flow enters the turbine chamber, drives the air turbine, and exits through the discharge opening and connecting socket. The bristles of the brush roller act through the vacuum air port on the surface to be worked on for which purpose the air turbine must make available a sufficient amount of drive power. Since the vacuum air flow can provide only a limited drive power, the air turbine is supported in a complex fashion so that a power loss as little as possible occurs. This support is complex and, within a line of products, can lead to great fluctuations in regard to the drive power acting on the brush roller because of tolerances.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a vacuum cleaning tool with a brush roller whose driving air turbine has a support that has only minimal power loss and, within a line of products, ensures minimal fluctuation of turbine power.

In accordance with the present invention, this is achieved in that the base member of the air turbine is fixedly attached to a bushing and the bushing is rotatably supported on a support shaft supported in the housing.

The air turbine according to the invention is supported by means of a bushing on a support shaft that is mounted in the housing, wherein the support shaft is supported within the housing. Tolerances occurring during mounting of the support shaft, comprised preferably of metal, have no effect on the supporting action of the air turbine itself. In particular, alignment errors of the holder provided in the housing for the support shaft have no effect on the support action of the turbine. The supporting properties are determined exclusively by the pair support shaft/bushing, and this pair is independent of size tolerances of the housing. The support action according to the invention not only ensures a uniform turbine power within a line of products but also provides a support that can be mounted easily by auxiliary personnel having no special mechanical skills.

In a special embodiment, the support shaft is mounted with one end, expediently with both ends, by means of bearings in the housing wherein the bearings can be mounted in the outer housing walls or in the inner housing walls within appropriate receptacles. Preferably, the support shaft is fixedly secured in the housing, i.e., it cannot rotate in the housing.

A simple drive connection is achieved in that the bushing projects at least at one end from the base member of the air turbine and a drive wheel of a drive is supported thereon. Expediently, a belt drive is provided that provides in a simple way a drive connection between the air turbine and the brush roller.

In order to make available at the brush roller a satisfactory torque, it is provided to arrange the air turbine with a portion of its diameter (i.e., a radial length that corresponds to a portion of the diameter) in a turbine channel projecting into the turbine chamber. This configuration of the turbine channel can be realized independent of the afore described invention. Expediently, the air turbine is arranged within the turbine channel in such a way that it projects by a radial length that is greater than its radius into the turbine channel. The turbine channel itself ends advantageously in the turbine chamber at a spacing in front of the discharge opening into the connecting socket wherein the width of the turbine channel corresponds approximately to the axial width of the air turbine.

The bushing of the air turbine can extend through the sidewalls of the turbine channel and is axially supported outside of the turbine channel in bearings fixedly attached to the housing. In this way, axial oscillation of the air turbine is prevented.

According to a further invention, the connecting socket has a stepped inner diameter in order to receive connecting tubes of different diameters. A first section adjacent to the connecting opening has a first inner diameter and a second section neighboring the turbine chamber has a second inner diameter. The first inner diameter is greater than the second inner diameter so that through the first section connecting tubes with smaller inner diameters can be inserted into the second section. Connecting tubes with greater diameters are inserted into the first section approximately in a seal-tight way. The sections with stepped inner diameter are provided on a socket insert that is separate from the connecting socket, wherein the socket insert is expediently seal-tightly inserted into the connecting socket and is locked therein.

Between the first and second sections there is expediently a circumferentially extending shoulder that forms a stop for the insertion depth of connecting tubes with greater outer diameter. For facilitating threading of a connecting tube and for broadening the diameter range of connectable tubes, it is provided that the inner diameter of one section widens in the flow direction of the vacuum air flow.

By arranging several vacuum air ports, of which at least one extends from the bottom of the working chamber into the front end face of the housing, a large mechanical action area for the brush roller is provided locally without the upholstery or the like to be cleaned penetrating too deep into the working chamber of the vacuum cleaning tool. The spatial configuration of the vacuum air ports enables excellent cleaning of corners, seams or the like. Since the partial vacuum air flows entering through the vacuum air ports, respectively, are combined in the working chamber and pass through the turbine chamber as a common vacuum air flow and drive the air turbine, a high torque and thus an excellent mechanical cleaning action are obtained.

Expediently, the vacuum air ports are approximately of identical configuration; in particular, they are positioned at identical, preferably minimal, spacing adjacent to one another.

When a vacuum air port extends from the bottom of the working chamber into the front end face of the housing, a configuration results that enables also excellent cleaning of corners, seams or the like. The vacuum air port extends across the housing edge formed by the bottom of the working chamber and the end face of the housing upwardly from the bottom into the end face of the housing.

The drive of the brush roller is realized by means of a belt drive wherein the belt pulley that is fixedly connected to the brush roller is not provided at the end of the brush roller but between the ends of the brush roller on its base member. In connection with the several vacuum air ports, the belt pulley of the brush roller is to be arranged on the brush roller in the area between the vacuum air ports. The housing web that remains between two vacuum air ports can thus cover the belt pulley and the driving belt so that the belt drive, despite the large surface area opening of the working chamber provided by the large vacuum air ports, has no parts that are open to the exterior.

By means of an advantageous spatial arrangement of the discharge opening, the turbine, and the brush roller in such a way that the center point of the discharge opening into the connecting socket, the air turbine axis, and the axis of rotation of the brush roller are positioned approximately in a common plane, a vacuum cleaning tool is provided that is easy to handle and has a great performance.

Expediently, the base member is provided with a widened diameter portion on which the belt pulley is secured. A part of the belt pulley, preferably the entire belt pulley, can be formed as a unitary part of the base member of the brush roller.

When the housing web remaining between the two vacuum air ports covers the belt pulley and the driving belt, the design of the belt pulley and of the housing web can provide essentially a closed receiving space or chamber for the driving belt.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective illustration of a vacuum cleaning tool according to the invention.

FIG. 2 is a side view of the vacuum cleaning tool according to FIG. 1.

FIG. 3 is a front view of the vacuum cleaning tool according to FIG. 1.

FIG. 4 is a perspective illustration of the bottom side of the vacuum cleaning tool according to FIG. 1.

FIG. 5 shows the vacuum cleaning tool according to the invention as shown in FIG. 1 with the housing top part removed.

FIG. 6 is a longitudinal section of the vacuum cleaning tool according to FIG. 1.

FIG. 7 is a horizontal section of the vacuum cleaning tool according to FIG. 1.

FIG. 8 is a detail view of a belt pulley of a belt drive arranged on a base member of a brush roller.

FIG. 9 is a plan view onto the open vacuum cleaning tool according to FIG. 1.

FIG. 10 shows an axial section of the support arrangement of the air turbine.

FIG. 11 shows a further longitudinal section of the vacuum cleaning tool according to FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The vacuum cleaning tool 1 according to the invention illustrated in the Figures is provided to be connected to a vacuum hose of a vacuum cleaning device, not illustrated, particularly a vacuum cleaner. For this purpose, the housing 2 assembled from a housing top part 2b and a housing bottom part 2a is provided at its rearward end 3 with a connecting socket 4 that is formed as a unitary or monolithic part of the housing 2. As can be seen in particular in the section illustrations of FIG. 6 and FIG. 7, a socket insert 5 is inserted into the connecting socket 4 (see section illustration of FIG. 6); the socket insert 5 has a stepped inner diameter S1, S2 in order to receive in a vacuum-tight way connecting tubes of different diameters. For this purpose, the first section 71 formed at the open end 104 is provided with an inner diameter S1 that is greater than the inner diameter S2 of the inwardly positioned second section 72 that neighbors the turbine chamber 11. Preferably, the diameters of the sections 71, 72 taper in the flow direction of the vacuum air flow 30. The socket insert 5 changes approximately at half its insertion length from the greater inner diameter S1 to the smaller inner diameter S2. Expediently, between the first section 71 and the second section 72 of the socket insert 5 a shoulder, preferably an annular shoulder, 73 is formed that serves as a stop for the insertion depth of connecting tubes with greater diameter.

The socket insert 5 is secured by a catch 6 captively within the connecting socket 4. After assembly of the housing parts 2a and 2b at the separation plane 2c of the housing 2 the socket insert 5 is inserted axially into the open end 104 of the connecting socket 4 until the catch 6 locks in place and the socket insert 5 that is manufactured separately from the connecting socket 4 is captively secured in the connecting socket 4.

The leading end 7 of the vacuum cleaning tool 1 is designed as a working chamber 8 that extends essentially transversely, in particular at a right angle, to the longitudinal axis 9 of the vacuum cleaning tool 1. The longitudinal axis 9 extends in the working direction 10 of the vacuum cleaning tool 1 from the rearward end 3 to the leading end 7.

Between the working chamber 8 and the connecting socket 4, a turbine chamber 11 is provided in the housing 2; the turbine chamber 11 houses an air turbine 12 (FIG. 5). The design of the vacuum cleaning tool 1 is such that the housing 2 of the vacuum cleaning tool 1 in the area between the turbine chamber 11 and the working chamber 8 has a waist. This waist 13 can be seen in FIGS. 2, 4, and 6 and is the result of the diameter K of the turbine chamber 11 being significantly greater than the diameter A of the working chamber 8 (FIG. 6). Since moreover the arrangement is such that the axis of rotation 14 of the brush roller 15 rotatingly supported in the working chamber 8 and the turbine axis 16 as well as the center point 17 of the discharge opening 18 that opens into the connecting socket 4 are positioned approximately in a common plane 19, the vacuum cleaning tool 1 according to the invention has a configuration that essentially extends with its longitudinal axis 9 in the working direction 10. By means of this configuration, the plane 19 is approximately a plane of symmetry of the vacuum cleaning tool.

In the bottom 20 of the working chamber 8 several vacuum air ports 21, 22, 23 are formed that are positioned adjacent to one another in a direction transverse to the longitudinal axis 9 of the vacuum cleaning tool 1. As shown in FIG. 3 and FIG. 4, the outer vacuum air ports 21 and 23 are identically designed while the central vacuum air port 22 is designed approximately like the outer vacuum air ports 21, 23. In this connection, all of the vacuum air ports extend from the bottom 20 of the working chamber 8 across the housing edge 51 into the front end face 24 of the working chamber 8 or of the housing 2. The vacuum air ports, as can be seen in the front view of FIG. 3, are designed like an archway. In the illustrated embodiment, the central vacuum air port 22 extends farthest upwardly in the end face 24; the outer vacuum air ports 21 and 23 have a lower height H in the end face 24.

In operation of the vacuum cleaning tool, a partial vacuum air flow 31, 32, 33 passes through each one of the vacuum air ports 21, 22, 23 into the housing 2; the partial vacuum air flows 31-33 then flow as a common vacuum air flow 30 through the connecting socket 4 into the vacuum cleaning device.

For guiding the vacuum air flow between the working chamber 8 and the turbine chamber 11, a connecting opening 25 is provided as illustrated particularly in FIGS. 5 to 7. Through the connecting opening 25 the partial air flows 31, 32, 33 that combine to a common vacuum air flow 30 flow into the turbine chamber 11, drive the air turbine 12 arranged within the turbine chamber 11 at high speed, and exit the vacuum cleaning tool 1 through the connecting socket 4.

The air turbine 12 configured as a flow-through turbine with a vane-free center drives by a belt drive 26 the brush roller 15 that is rotatably supported in the working chamber 8. The axis of rotation 14 of the brush roller 15 is positioned transversely to the longitudinal axis 9 of the housing 2. The brush roller 15 is comprised of a base member 27 that has one or several rows of bristle arrangements 28 arranged in spiral. The bristles project minimally through the vacuum air ports 21, 22, 23 and act on the surface to be treated.

The belt drive 24 (FIG. 5, FIG. 10) is comprised of a driving belt 29 that, as shown in particular in FIG. 11, is preferably a toothed belt. The driving belt 29 is positioned on a drive wheel 34 that is fixedly connected to the air turbine 12 as well as on a belt pulley 35 of the brush roller 15. With regard to its diameter, the drive wheel 34 is significantly smaller than the belt pulley 35 of the brush roller 15.

As illustrated in FIG. 7 and FIG. 8, the belt pulley 35 is fixedly connected to a portion 36 having a larger diameter relative to the base member 27. In a particular configuration a part of the belt pulley 35 is a unitary part of the base member 27 of the brush roller 15. As illustrated in FIG. 8, one lateral flank of the belt pulley is formed like an annular flange 37 as a unitary part of the base member 27 in the area of the portion 36 having the larger diameter. The second part of the belt pulley that is configured as an L-shaped base member 38 is pushed onto the portion 36 having the larger diameter until it meets the flange 37 and is then fixedly attached. The annular flange 37 of the base member 27 and the pushed-on L-shaped base member 38 together form the belt pulley 35.

The belt pulley 35 which is fixedly connected to the brush roller 15 is positioned between the ends 40 and 41 of the brush roller 15; this can be seen in particular in FIG. 9. The arrangement is such that the belt pulley 35 divides the length of the brush roller 15 in a ratio of 1/3 to 2/3. The position of the brush roller 15 in the housing 2 is secured by bearings 39 arranged on the ends 40 and 41 and mounted in the housing. The arrangement is provided such that the belt pulley 35 is positioned precisely between two vacuum air ports 22 and 23 so that the housing web 32 positioned between the two ports 22, 23 covers the belt pulley 35 and the belt 29. In this connection, the housing web 42, as shown in FIG. 7 and FIG. 8, is positioned at only minimal spacing relative to the outer circumference of the belt pulley 38 so that the housing web 42 and the belt pulley 35 (lateral flank or annular flange 37 and base member 38) delimit a receiving space (chamber) 43 for the driving belt 29. In the area of the leading end face 24, the housing web 42 has inner webs 44 that are arranged in the area of the housing end wall 24 and impart to the web 42 a U-shaped cross-section (FIG. 7). The opening of the U is facing the belt pulley 35 so that the receiving space 43 extends to the ceiling area of the working chamber 8.

In order to generate sufficient torque at the brush roller 15, it is provided that the air turbine 12 is arranged with a portion of its diameter D in a turbine channel 45 that projects into the turbine chamber 11. The turbine channel 45 is illustrated in FIG. 7 and FIG. 9. Is it is comprised essentially of lateral walls 46 adjoining the connecting opening 25; the lateral walls 46, as shown in FIG. 11, extend across the entire height T of the turbine chamber 12. The turbine channel 45 is thus delimited by the bottom of the housing bottom part 2a, the lateral walls 46, and the ceiling of the housing top part 2b. The turbine channel 45 has free ends within the turbine chamber 11 ending at a spacing in front of the discharge opening 18 that opens into the connecting socket 4. The air turbine 12 projects across a depth into the turbine channel 45 that is greater than the radius of the air turbine 12 and is preferably smaller than its diameter D.

The base member 112 of the air turbine or its hub 47 can be arranged between the lateral walls 46 of the turbine channel 45. The spacing c of the lateral walls 46 is then minimally greater than the axial width B of the air turbine so that the hub 47 of the air turbine 12 is tightly held between the lateral walls 46. The vacuum air flow 30 flowing in through the connecting opening 25 must therefore flow between the turbine vanes 53 into the vane-free center 54 of the air turbine 12 and from the free center must flow out by passing through the vane arrangement again. The air turbine 12 itself is comprised of a central disc with turbine vanes arranged on both sides and connected or secured only by the central disc. The vane ring is open toward the free end face wherein the vanes of one side are displaced relative to the vanes of the other side in the circumferential direction. The vacuum air flow 30 is divided approximately uniformly onto the two vane arrangements of the two axial sides of the central disc.

The connecting opening 25 corresponds advantageously to the width c of the turbine channel 45 and has a height that is less than its width. The connecting opening 25 is approximately slot-shaped when viewed in an end view.

The connecting opening 25 is positioned, as shown in FIG. 6, underneath a plane 49 that is determined by the turbine axis 16 and the center point 17 of the discharge opening 18 that opens into the connecting socket 4. Preferably, the top edge 50 of the connecting opening is positioned in this imaginary plane 49.

Expediently, the axis of rotation 14 of the brush roller 15 is arranged above the imaginary plane 49 that is determined by the turbine axis 16 and the center point 17 of the discharge opening 18.

In order to provide the driving air turbine 12 with a simple support that can be mounted easily and is essentially loss-free, it is provided to mount the base member 112 of the air turbine 12 fixedly, in particular secured against rotation, on a bushing 147 that preferably projects at one end 134 from the base member hub 47 and carries the drive wheel 34 for the driving belt 29 of the belt drive; the drive wheel 34 is fixedly connected to the bushing 147. In the embodiment according to FIG. 10, the bushing 147 is of a unitary configuration. It can be expedient to design the bushing 147 of a multi-part configuration, for example, in that into each end of the base member hub 47 a shorter bushing is inserted. The base member hub 47 is then supported at both axial ends.

Advantageously, the bushing 147 can be integrally cast into the base member 112.

The bushing 147 is supported on a support shaft 116 that is preferably secured at both axial ends 148 in the housing 2. As shown in the embodiment according to FIG. 10, the axial ends 148 of the shaft 116 are supported by a bearing 48, respectively, in the housing. The bearing 48 is received in a corresponding receptacle of the housing bottom part 2a and is secured by the web 102 of the housing top part 2b in the receptacle in a positive-locking way. It can be expedient to secure the support shaft 116 fixedly in the housing, i.e., so that the shaft is prevented from rotating. For a loss-free supporting action of the bushing 147 a fixed securing action (no rotation) of the support shaft 116 is however not mandatory. It can be advantageous to support the support shaft 116 in the housing 2 so as to be rotatable so that the support shaft 116 itself is rotatably secured in the housing and the air turbine 12 is rotatably supported by its bushing 147 on the rotatable support shaft 116.

As shown in the embodiment according to FIG. 10, the hub 47 of the air turbine 12 advantageously extends through the wall 46 of the turbine channel 45 wherein the bushing 147 is positioned with minimal play between the bearings 48 fixedly mounted in the housing. In this way, axial oscillating movements of the air turbine12 are prevented. A simple, easily reproducible axial support action is achieved.

While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.