EP0737437B1 - Vacuum cleaner nozzle having wheels at the rear - Google Patents

Description

The present invention relates to a vacuum cleaner nozzle comprising a housing which has a top and at least one rear wall element, a sole disposed under the housing, and two rear wheels, capable of roll on the ground, arranged at the rear of the housing and mounted on an axis of rotation arranged in the longitudinal direction of the housing. This axis of rotation has a middle portion and two end portions, and is supported by at least one support member cooperating with said element rear wall. Each rear wheel includes a housing for one of the end portions of the axis.

In known nozzles of this type (see document DE-A-30 09648), the two wheels are mounted free to rotate relative to the axis of rotation and therefore include, each, a hub rotating relative to the axis, and fixing parts such as circlips, washers and screws. Editing is therefore a relatively complicated operation and requires many parts.

Furthermore, it has been discovered that allowing the wheels to turning relative to the axis, therefore one relative to the other, does not constitute necessarily an advantage. Indeed, with this arrangement, the trajectory of the crevice, when the user pushes or pulls it, is not naturally straight. Consequently, insofar as, in particular for relatively large floor areas, it is desirable to clean in one passage, a whole strip of soil, the user is often forced to provide, in addition to the initial pushing or pulling effort, a guiding on a straight path, avoiding lateral movement of the nozzle.

The present invention aims to remedy these drawbacks by proposing a nozzle for which, in order to limit the weight and the costs of manufacturing, the assembly of the rear wheels is simplified, the number of parts used for this assembly is limited and these wheels are integral one of the other in rotation.

For this purpose, the support member constitutes a support bearing by ratio at which the axis of rotation is free to rotate. For each wheel rear, the housing is constituted by a cylindrical sleeve made of material plastic in which an end portion of the axis of rotation is likely to be force-fitted. In addition, each end portion of the axis of rotation includes locking means inside the sleeve in which it is engaged.

Thanks to this conformation, the mounting of the rear wheels is particularly simple, since it consists in placing the axis of rotation in its bearing (s) and press-fit the wheel sleeves on the two end portions of this axis. Furthermore, this provision constitutes a particularly simple way to secure the rotating wheels. The only parts required are the support bearing (s) of the axle rotation, this axis of rotation and the two wheels fitted with their sleeves respective.

Preferably, the axis of rotation is metallic, while the wheels, which are made in one piece, are made of plastic material relative flexibility, so that the blocking means of each end portion of the axis of rotation inside the sleeve of each wheel can simply be constituted by means of hooking this axis in the plastic.

Advantageously, the rotation lock is ensured by axial grooves, while locking in translation is provided by a radial attachment face.

The invention will be well understood and its advantages will appear better at reading the following detailed description of an embodiment shown by way of nonlimiting example.

• la figure 1 est une vue en coupe du suceur selon l'invention dans un plan de symétrie antéro-postérieur,
• la figure 2 est une vue éclatée montrant les deux roues, l'une d'entre elles étant représentée en coupe axiale et l'autre en vue extérieure, et l'axe de rotation,
• la figure 3 est une vue de détail d'une portion d'extrémité de l'axe de rotation, et
• la figure 4 est une vue en coupe selon la ligne IV-IV de la figure 1, sur laquelle, pour simplifier, les roues sont schématisées en vue extérieure.

The description refers to the accompanying drawings in which:

• FIG. 1 is a sectional view of the nozzle according to the invention in an anteroposterior plane of symmetry,
• FIG. 2 is an exploded view showing the two wheels, one of them being shown in axial section and the other in external view, and the axis of rotation,
• FIG. 3 is a detailed view of an end portion of the axis of rotation, and
• Figure 4 is a sectional view along the line IV-IV of Figure 1, on which, for simplicity, the wheels are shown schematically in external view.

Figure 1 shows a vacuum cleaner nozzle comprising a housing 10 susceptible, by means of a connection tube 12 directed upwards and backwards, to be connected to a suction tube (not shown). The housing has a top 14 and at least one rear wall element. A sole 18 disposed under the housing has a suction opening 20, connected to a suction channel 22 located inside the housing, this channel being itself connected to the suction pipe 12.

In the example shown, a scraper member is located behind the suction opening 20. In a manner known per se, this scraper member could be replaced by a retractable brush, mounted on a plate mobile, and capable of being lowered through marginal slots in the sole to come into contact with the ground or to be raised to be retracted.

The nozzle also includes rear wheels 26 and 28, only the wheel 28 being visible in FIG. 1, capable of rolling on the ground (shown by line l 1), and arranged at the rear of the housing 10. These wheels are mounted on an axis of rotation 30 disposed in the longitudinal direction of the housing, that is to say perpendicular to the cutting plane of Figure 1.

In general, we consider that the management anteroposterior of the squeegee is that in which, in normal situation of use, one pushes forward or one pulls towards the bitter the nozzle, while that its longitudinal direction is perpendicular to this anteroposterior direction.

The nozzle of the nozzle of FIG. 1 has a first part 12a cooperating with the housing and pivotally mounted around of an axis whose position coincides with that of the axis of rotation 30 of wheels, and a second part 12b fitted in the first.

This is only an example of an embodiment, the connection tubing can indeed be pivotally mounted about an axis parallel to the axis of wheel rotation and distant from it.

As best seen in Figure 2, the axis of rotation 30 has a middle part 32 and two end portions, respectively 36 and 38.

The end portion 36 is capable of being forcibly engaged in a cylindrical sleeve 27 of the wheel 26, and the end portion 38 is capable of being force fitted into the sleeve 29 of the wheel 28.

The middle part 32 of the axis 30 is arranged in a bearing of support, cooperating with the rear wall element of the housing, relative to which this axis 30 is free to rotate, and which will be described more precisely below with reference to FIG. 4.

Each end portion 36 or 38 of the axis of rotation comprises blocking means inside the sleeve 27 or 29 in which it is engaged.

We will now describe these locking means in detail with reference in Figures 2 and 3. They include a grooved portion 40 whose splines are arranged axially. The tops 41 of these grooves are find at a radial distance D1 from the geometric center of the axis 30 (located on the axis of symmetry C) greater than the radius R1 of the internal periphery of the sleeve in which the end portion considered is engaged, before inserting this end portion. In other words, the vertices or the edges of the grooves are substantially located on a circle of radius greater than that of the inner periphery of the sleeve.

The sleeves being made of a plastic material having a certain flexibility or a certain softness, the grooves of the portion 40 line the inside of the sleeves when the end portions of the axle are engaged in these sleeves. Because of the difference, advantageously on the order of 0.2 to 0.4 mm, between the internal radius of the sleeves and the radial distance from the tops of the grooves, the scratches thus practiced are deep enough for the wheels to stop rotating relation to the axis is effective.

The locking means of each end portion 36 or 38 to the interior of the sleeve 27 or 29 also have at least one face radial attachment. In the example shown, two radial faces attachment 42 and 44 are present. They are both made up of a radial face of a shoulder, which faces the middle portion 32 axis 30 and which has a substantially circular external edge, 43 and 45 respectively, whose radius is substantially equal to the distance radial D1 of the tops of the grooves.

Thus, when the end portions are engaged inside the sleeves, these sharp edges catch on the inside of the sleeve and realize thus an axial locking of the wheels relative to the sleeve.

More specifically, the end portion 38 of FIG. 3 has, successively arranged in the direction from the end 33 of the axis 30 towards its middle portion 32, that is to say in the direction indicated by the arrow F, an extreme cylindrical portion 46, a first annular groove 48, the grooved portion 40, and a second annular groove 50.

The radius of the extreme cylindrical portion 46 is substantially equal to the radial distance D1 from the tops of the grooves and therefore greater than the radius R1 of the internal periphery of the sleeve 29. On the other hand, the radii D2 and D3 of grooves 48 and 50 are lower or, at least, substantially equal, to radius R1. The radii D2 and D3 are preferably equal.

The first attachment face 42 is constituted by the annular edge throat 48 closest to the end 33. It is also possible consider that this attachment face is constituted by the radial face of the cylindrical portion 46 directed towards the middle portion 32 of the axis.

Similarly, the second attachment face 44 is formed by the nearest substantially annular edge of the groove 50 of the end 33. It can also be considered that this face 44 is constituted by the radial face of the grooved portion 40 directed towards the part median 32 of the axis.

The edge 43 of the first face 42 is circular, while the edge 45 of the face 44 can be serrated due to the presence of the grooves. The main thing is that the current radius of each of these edges is greater to the radius R1 of the internal periphery of the sleeve in which they are engaged.

Advantageously, the radius of the middle part of the axis is equal to that of the cylindrical end portion 46, itself substantially equal to the distance D1. For example, this radius can be of the order of 2.5 mm, while the radii D2 and D3 are of the order of 2.2 to 2.3 mm.

The radius R1 of the inner peripheries of the sleeves, i.e. their radius before insertion of the end portions, may be of the order of 2.2 to 2.3 mm.

To facilitate the insertion of the end portions of the axle into the sleeves, we can foresee that the entry of these sleeves is slightly wider than their current part.

Advantageously, it can also be provided that the end of each end portion of the axis 30 has a centering ramp substantially frustoconical flared in the direction going from the end considered, towards the middle portion 32 of the axis. So the end 33 of the end portion 38 has the ramp 47.

Advantageously, to facilitate the insertion of each portion end in each sleeve beyond the grooved portion 40, the edge of the groove 50 further from the end 33 can also be substantially tapered, flared in the direction towards the middle part 32 of the axis. The two wheels, and therefore the sleeves 27 and 29, are identical, as well as the two end portions of the axis.

In FIG. 2, the wheel 28 is shown in axial section, while the wheel 26 is shown in external view. The two wheels being identical, only wheel 28 is described. It has an external wall 50 substantially cylindrical, which has a first open side 52 and a second side closed by a side wall 54. The cylindrical sleeve 29 is disposed inside the outer wall 50 and has a first end 29a open towards the first side 52 of the wall 50, and a second end 29b closed. The latter is likely to constitute a stop for the end 33 of the axis of rotation when the portion end 38 is engaged in the sleeve 29.

We see in Figure 2 that the end 29b is located inside the wheel, away from the axial end of the wall 50 opposite the side 52 of the latter. This allows for relatively long wheels without have to fit the axis over their entire length. In fact, the sleeve hollow cylindrical 29 is provided with a connection extension 56 which extends, towards the side wall 54 of the wheel, beyond the second end 29b of the sleeve. This extension connects the sleeve to the wall side 54 and is connected to the cylindrical wall 50 by connecting webs 58. We see that the end 57 of the extension 56 opposite the sleeve 29 is open on the side wall 54.

This arrangement makes it possible to manufacture the wheel in a simple manner, by one piece molding. The presence of extension 56 and the sails of connection 58 ensures the desired maintenance of the sleeve 29 at inside the wheel. Note that the connecting sails extend over the entire length of the extension 56, which they actually connect to the external part 50 and to the side wall 54. They also extend over a short length of the sleeve 29 beyond its end 29b.

However, we note that most of the length of the sleeve 29 is free of connecting webs. We saw previously that the end portion 38 of the axis is force fitted into this sleeve. The providing that a significant portion of this sleeve extending from of its free end, that is to say free of connecting veils makes it possible to make sure that the rigidity of this portion is not too great to oppose the press fitting of the end of the axis, which, in particular due to differences in radius previously mentioned and the presence of splines, may slightly deform the sleeve.

We also note that the end 29a of the sleeve is located outwards, slightly beyond the open side 52 of the wall 50.

This wall 50 of the wheel 29 has an annular tread 60 which projects radially from it and is located on the first side of this wall. The free axial end of the tread 60 coincides with the open side 52 of the wall 50, and the tread extends axially towards the side wall 54 over a determined length l , for example of the order of 1 cm , advantageously between 1 / 6th and 1 / 5th of the total length L of the external cylindrical wall 50. As can be seen in FIG. 2, this tread 60 has a slightly grainy surface. The same can be said for the entire outer surface of the wheel.

When the two wheels are mounted, as shown in Figure 4, the two treads 60 determine, particularly on hard ground, privileged rolling zones, located near the axis of symmetry To who is in the median anteroposterior plane of the squeegee.

It was previously indicated that the fact that the two wheels are integral in rotation allowed to give the nozzle a trajectory naturally straight. Although this is the most common trajectory used, the user is sometimes led to search for a curved trajectory, for example to get around certain obstacles. If the wheels carried always along their entire length, it would be necessary, to obtain such trajectory, completely lift one of the wheels by turning the nozzle around axis A. Insofar as the two treads are close to this axis, it is much easier to rotate the squeegee by only printing a slight movement. The grainy surface of the strips of rolling allows to increase the grip of the wheels in particular on ground hard and prevent them from spinning.

Note that on carpets or rugs, the tread can constitute a main support area, but the wheels can carry on any their length.

We saw previously that the sleeves were advantageously made of a relatively flexible or soft plastic. In fact, wheels are made in one piece from the same plastic. So, the outer wall 50 of each wheel may be slightly deformable elastically in the radial direction. It can therefore be slightly crushed contact with the ground, which has the advantage of increasing the surface grip.

Referring to Figures 1 and 4, we now describe more precisely the means forming a support bearing for the axis of rotation 30.

The rear wall element 16 of the nozzle has an opening central which has two lateral edges 64 and 66, perpendicular to the longitudinal direction of the squeegee. In fact, seen from the back of the squeegee, the opening 62 is generally rectangular and comprises, in addition to the two lateral edges 64 and 66, an upper edge 62a and a lower edge 62b substantially horizontal.

The lateral edges 64 and 66 are each provided with a circular orifice, respectively 65 and 67, whose diameter is substantially equal to the diameter current of the axis 30, that is to say the diameter of the middle part 32 of this axis. The two orifices 65 and 67 are aligned on an axis X parallel to the longitudinal direction of the squeegee, which corresponds to line C in FIG. 3.

The suction tube 12, or at least the first part 12a of this tubing, has a front end 70 capable of being engaged in the central opening 62. This front end is provided with a tube longitudinal 72 whose internal diameter is substantially equal to the diameter of the middle part 32 of the axis 30. As can be seen in the figures, when the front end 70 is actually engaged in the opening central 62, this tube 72 extends longitudinally between the orifices 65 and 67 lateral edges 64 and 66 of this opening.

When the wheels are mounted, the axle 30 is therefore engaged in the orifices 65 and 67 and in the tube 72. These are therefore both the lateral edges 64 and 66, as well as the tube 72 which play the role of the support bearing for the axis.

To ensure the efficiency of the wheels, it is important to ensure that, whatever the type of soil, the grip of the wheels on the ground is greater than any friction forces that may arise between the axis 30 and the internal wall of the tube 72, taking into account the fact that the contact zone between the axis and the tube extends over a relatively length important.

To do this, the inner surface of the tube is smooth as is the middle part of the axis, while, as we saw previously, at minus the treads 60 are relatively rough or grainy. Likewise, the axial internal face of the orifices 65 and 67 is smooth. Note that the axis can be metallic, while the tube is plastic, and that these two materials do not have affinities between them capable of causing significant friction.

Furthermore, to axially chock the wheels, it is important that they find practically in contact with the lateral edges 64 and 66. In the since these edges are obviously fixed, it is important to avoid that the wheels do not rub too much against them, which would affect their rotation. It's for this reason that the sleeve of each wheel extends slightly towards the outside beyond the open edge of the wheel, so that only the end sleeve is likely to come into contact with the side edge adjacent, this contact surface is small enough that the forces friction are negligible.

In the event that the pivot axis of the connection pipe does not does not coincide with the axis of rotation of the wheels, the support bearing for these wheels can be formed in one piece with the rear wall of the housing, or be made in a room attached to this wall.

Claims (9)

1. Vacuum cleaner nozzle including a case (10) having a top (14) and at least one rear wall element (16), a sole piece (18) arranged under the case and two rear wheels (26, 28) which can run on the ground (1₁), arranged at the rear of the case and mounted on a rotation shaft (30) arranged in the longitudinal direction of the case, this rotation shaft having a median part (32) and two end portions (36, 38) and being supported by at least one support organ co-operating with the said rear wall element, each rear wheel (26, 28) comprising a housing (27, 29) for one of the end portions (36, 38) of the shaft,
      characterised by the fact that the support organ constitutes a support bearing (64, 66, 72) relative to which the rotation shaft (30) is free to rotate,

   by the fact that for each rear wheel (26, 28), the housing consists of a cylindrical sleeve (27, 29) made of plastics material in which an end portion (36, 38) of the rotation shaft can be force-fitted, and

   by the fact that each end portion (36, 38) of the rotation shaft (30) includes locking means (40, 42, 44) inside the sleeve (27, 29) in which it is engaged.
2. Vacuum cleaner nozzle as described in claim 1, characterised by the fact that each end portion (36, 38) of the rotation shaft (30) includes a fluted portion (40) provided with axial fluting the peaks (41) of which are at a radial distance (D1) from the geometric centre (C) of the rotation shaft (30) greater than the radius (R1) of the internal circumference of the sleeve (27, 29) in which the end portion (36, 38) is engaged, before insertion of the latter, and a radial catching surface (42, 44), the latter consisting of a radial surface of a shoulder facing towards the median portion (32) of the shaft (30) and having a substantially circular outer ridge of radius substantially equal to the radial distance (D1) of the peaks (41) of the fluting.
3. Vacuum cleaner nozzle as described in claim 2, characterised by the fact that each end portion (36, 38) of the rotation shaft (30) has, arranged successively in the direction passing from the end (33) towards the median portion (32) of the shaft, an end cylindrical portion (46) the radius of which is substantially equal to the radial distance (D1) of the peaks (41) of the fluting, a first annular groove (48) having a first radial catching surface (42), the fluted portion (40), and a second annular groove (50) having a second radial catching surface (44).
4. Vacuum cleaner nozzle as described in any one of claims 1 to 3, characterised by the fact that the end of each end portion (36, 38) of the rotation shaft (30) has a centring incline (47) substantially in the form of a truncated cone opening out in the direction passing from the end (33) in question towards the median part (32) of the shaft.
5. Vacuum cleaner nozzle as described in any one of claims 1 to 4, characterised by the fact that each rear wheel (26, 28) is hollow, formed in one piece and includes a substantially cylindrical outer wall (50), having a first side (52) open and a second side closed by a lateral wall (54), the cylindrical sleeve (27, 29) being arranged axially within the outer wall (50) and having a first end (29a) open towards the first side (52) of this wall and a second closed end (29b), able to co-operate as a stop with an end (33) of the rotation shaft (30).
6. Vacuum cleaner nozzle as described in claim 5, characterised by the fact that, for each rear wheel (26, 28), the cylindrical sleeve (29) is provided with a connecting extension (56) extending towards the lateral wall (54) of the wheel in question, beyond the second end (29b) of the sleeve, and connecting the sleeve to this lateral wall (54), this connecting extension being joined to the cylindrical wall (50) of this wheel by joining webs (58).
7. Vacuum cleaner nozzle as described in either of claims 5 or 6, characterised by the fact that the outer wall (50) of each rear wheel (26, 28) has an annular running strip (60) projecting radially relative to this wall (50), situated on the first side (52) of the latter and having a granulated surface.
8. Vacuum cleaner nozzle as described in any one of claims 5 to 7, characterised by the fact that the outer wall (50) of each rear wheel (26, 28) is slightly elastically deformable in the radial direction.
9. Vacuum cleaner nozzle as described in any one of claims 1 to 8, characterised by the fact that the rear wall element (16) includes a central opening (62) having two lateral edges (64, 66) perpendicular to the longitudinal direction of the nozzle and each provided with a circular orifice (65, 67) substantially equal in diameter to the running diameter of the rotation shaft of the rear wheels, the two orifices being aligned along an axis (X) parallel to the longitudinal direction of the nozzle, and by the fact that it includes a suction pipe (12) having a front end able to be engaged in the central opening, the said front end being provided with a longitudinal tube (72) having an internal diameter substantially equal to the diameter of the median part (32) of the rotation shaft (30) of the rear wheels and extending, when the front end (70) of the pipe is engaged in the central opening (62), between the orifices (66, 67) of the lateral edges (64, 66) of this opening.

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