The present invention relates to the sector of electric household appliances for performing cleaning by means of suction, such as a vacuum cleaner, a vacuum cleaner drum, an electric broom, a carpet beater, a cyclone vacuum cleaner or a similar apparatus. In particular it relates to the sector of tubes and telescopic extensions for such electric household appliances. The present invention relates, even more particularly, to a sleeve which can be associated with a telescopic extension, or with a non-telescopic tube or with an accessory or a handle. The present invention relates also to an assembly consisting of tubes and sleeve and an assembly method.
Telescopic extensions for electric household appliances in which an inner tube and an outer tube are configured to slide in a sealed manner one inside the other and assume a plurality of positions between a completely closed configuration and a completely extended configuration are known.
Based on the suction direction in a telescopic extension an input end and an output end are identified. The input end is typically removably fixed to a suction tool such as a so-called vacuum cleaner brush or vacuum cleaner nozzle (or head). The brush slides over the surface to be cleaned and sucks up solids or liquids such as dust, debris, crumbs or water. The material sucked up from the ground enters into the telescopic extension through the input end and exits the telescopic extension through the output end. Downstream of the telescopic extension the material sucked up from the ground is stored, passing optionally through another tube, for example a rigid or flexible tube of the spiralled type.
Similarly, depending on the suction direction, an input end and an output end are also identified for the inner tube and outer tube. In fact, the input end of the inner tube corresponds to the input end of the telescopic extension and the output end of the outer tube coincides with the output end of the telescopic extension.
In order to fix in a removable manner a vacuum cleaner brush to a telescopic extension a sleeve is mounted on that end of the telescopic extension to which the brush is to be fixed. The sleeve comprises a locking tooth which is pushed by means of a spring diametrically towards the inside of the sleeve (and the extension). A pushbutton allows the elastic pressure exerted on the locking tooth to be opposed so as to obtain an unlocked configuration in which it is possible to insert/remove the brush into/from the telescopic tube.
Similarly, a sleeve is mounted in order to mount a handle on a vacuum cleaner tube or in order to connect the inner tube to the outer tube in a telescopic extension.
The inventor has noticed that the steps of assembling a sleeve together with a tube (for example a telescopic extension) are relatively complex and may not be easily automated. Moreover, assembly of the various components of the sleeve may not be performed before mounting the sleeve on the tube of an electric household appliance and must be carried out when the telescopic extension is formed.
Manual assembly in turn results in a relatively high cost, with the result that assembly is uneconomical in those countries where the cost of labour is relatively high.
The inventor has realized that a major drawback of non-automated manual assembly and pre-assembly is the fact that a window for the pushbutton is formed in the tube. In practice the assembly of a known sleeve involves inserting the main body of the sleeve inside the tube and then inserting a spring and the pushbutton from the outside into the window and finally engaged a cover-piece with the pushbutton in order to keep it in position.
The inventor has realized that the assembly of a sleeve on a tube (preferably of a tubular extension for an electric household appliance) may be facilitated by forming a slit in the tube and not a window.
For the purposes of the present description and the claims, the term "slit" is understood as meaning an opening formed in any known manner in the wall of a tube in such a way as to be bounded by the tube wall on three sides. A slit is therefore open along the edge of the tube, but is closed by the wall of the tube along the two sides which extend in the longitudinal direction of the tube and the side which joins together the two longitudinal sides.
For the purposes of the present description and the claims, the term "window" is understood as meaning an opening formed in any known manner in the wall of a tube in such a way as to be bounded by the tube wall on four sides. The sides are preferably curved lines or segments.
Owing to the slit, the sleeve may be preassembled and may be mounted on the tube with a translation movement, thus resulting in simple and low-cost assembly.
Merely for the purposes of simpler illustration the present description and claims will refer mainly to a sleeve for a telescopic extension. However, the present invention is equally well applicable also to a non-telescopic extension and also, more generally, to a pair of tubes (qualified as "inner" and "outer" in relation to the sleeve). Therefore, for the purposes of the present invention, the expression "telescopic extension" must be understood in a wider sense so as to include also a non-telescopic extension and also an (outer) tube and an inner tube of a handle or an accessory (for example a vacuum cleaner brush).
According to one aspect of the present invention a sleeve for connecting together an outer tube and an inner tube of an electric household appliance is provided, the sleeve comprising:
The sleeve according to the present invention may advantageously be pre-assembled or mounted on the extension by fitting the outer tube onto it. While the sleeve is fitted onto the inner tube, the tooth of the pushbutton is inclined slightly in the unlocked position and then returns into the locking position once it is located in the end-of-travel position.
Advantageously the inner tube has a cavity (with a closed bottom) for the tooth. This prevents air leakages and therefore loss of power.
Preferably the tooth comprises a chamfered leading edge. This is advantageous at the moment when the sleeve is fitted onto the inner tube.
Preferably the tooth is integral with the actuating button. Therefore, according to the present invention, locking components separate from the actuating button are not provided.
Preferably the elastic member is a cylindrical spring seated inside a housing opposite said tooth and open towards the cover-piece. The cylindrical spring is kept in position by means of a pin and the cover-piece is easily positioned so as to retain the actuating button. In the locking position the axis of the cylindrical spring is substantially perpendicular to the tooth (to the bottom of the housing) and to the inner surface of the cover-piece. The fact that the spring works in an axial direction is advantageous and prevents any jamming.
Preferably the window is inside the seat delimited by a retaining wall. The window is not outside the housing, but is protected by it.
Preferably, the end of the main body opposite to the head end comprises a sealing lip, formed as one piece with the sleeve and configured to engage with the inner surface of the outer tube. The sleeve according to the present invention has a sealing lip integral with the rest of the sleeve. This ensures a better sealing performance and facilitates assembly.
According to embodiments, the main body also comprises a platform which is raised with respect to the surface of the side wall, the shape of said platform being substantially complementary to the shape of said slit. This compensates for the absence of material in the region of the slit.
According to embodiments, the platform is raised with respect to the rest of the side wall by a height substantially equal to the thickness of the wall of the outer tube.
According to embodiments, the circular ring comprises a closed-ring annular strip. The closed-ring annular strip may comprises a zone with a smaller width.
According to embodiments, the sleeve also comprises a retaining molding projecting radially outwards from the surface of the side wall, the molding being configured to engage inside a slot in the outer tube.
According to another aspect, the present invention relates to an assembly comprising a sleeve of the aforementioned type, an inner tube and an outer tube, wherein the inner tube comprises a cavity having a closed bottom configured to receive the tooth of the actuating button and wherein the outer tube comprises a slit. The inner tube and the outer tube may form part of a telescopic extension for a vacuum cleaner or the like. Alternatively, the inner tube forms part of an accessory or a handle.
According to another aspect of the present invention a method for mounting a sleeve between an inner tube and an outer tube is provided, the method comprising:
According to preferred embodiments, the sleeve is inserted inside the outer tube in an assembled configuration in which the pushbutton and the cover-piece are associated with the main body in an operating configuration.
The present invention will become clear from the following detailed description of examples of embodiment, to be read with reference to the attached figures, in which:
The sleeve 1 according to an embodiment of the present invention comprises a main body 10, a pushbutton 30, an elastic member 40 and a cover-piece 50. With reference to
The main body 10 has a more or less cylindrical shape with a more or less circular cross-section. Preferably, it is made by means of molding (for example injection molding) using a plastic or thermoplastic material.
The main body 10 comprises a head end 12, an opposite sealing end 14 and a side wall 16. The side wall 16 of the main body 10 is provided with a seat 20 for the actuating button 30 and a latch 22 for the cover-piece 30.
The head end 12 of the main body 10 comprises a circular ring 121 which is connected to the front edge of the main body 10, as shown in the cross-section of
Preferably, the circular ring 121 extends with a constant width along the whole circumference. However, it preferably forms a recess 123 facing the seat 20 for the actuating pushbutton 30. The function of this recess 123 in the circular ring 121 will become clear below. In any case, it is provided so as not to interfere with the actuating button 30.
The end 14 of the main body 10 opposite to the head end 12 comprises preferably a sealing lip 141. Preferably, the sealing lip 141 comprises a thinner strip which opens outwards slightly in the form of a cone. The sealing lip 141 is configured to engage with the inner surface of the tube 62 on which the sleeve 1 is mounted. The sealing lip 141 preferably is connected to the side surface 16 of the main body 10 of the sleeve 1 with an inclined surface 142.
The side wall 16 of the main body 10 of the sleeve 1 is generally a cylindrical surface substantially without projections or recesses. However, as shown in all of
The seat 20 comprises a retaining wall 21 projecting radially outwards. The retaining wall 21 is preferably U-shaped, namely is closed on three sides and open on one side. A groove 201 which defines an axis of rotation of the actuating button is preferably provided inside said retaining wall 21, on the bottom. Preferably, the groove 201 is divided into two separate portions.
As shown in
Preferably, latch members 22 configured to engage with the cover-piece 30 are present on the two opposite sides of the retaining wall 21.
Preferably, a platform 18 raised with respect to the remainder of the surface of the side wall 16 is present between the open side of the retaining wall 21 and the head end 12. Preferably, the platform 18 is raised by a height substantially corresponding to the thickness of the wall of the tube 62. Preferably the raised platform 18 is present also along the two opposite sides of the retaining wall 21. Preferably, along the two opposite sides of the retaining wall 21, the raised platform 18 has an edge 181 inclined to form a receiving surface.
Preferably, the main body 10 of the sleeve 1 comprises a retaining molding 19 projecting radially outwards from the surface of the side wall 16. Said molding 19 preferably is situated between the retaining wall 21 and the lip 141 and follows substantially the progression of the said lip.
Hereinbelow the pushbutton 30, shown in
The cover-piece 50 is mounted so to complete the aesthetic and functional features and provide a counter-surface for the said elastic member 40. In other words, when the cover-piece 50 is mounted and retained by the latch members 22, the elastic member 20 is located between the pin 33 and the internal surface of the cover-piece 50. If no pressure is exerted on the zone 31, the elastic member 40 presses elastically the tooth 34 downwards. The tooth 34 penetrates inside the window 24 and engages with a corresponding cavity in the inner tube. In this way, the inner tube is firmly locked to the tube 62. If a pressure is exerted on the pushbutton 30, the tooth 34 is raised against the elastic force of the elastic member 40 and no longer interferes with the inner tube.
Advantageously, the sleeve 1 according to the present invention may be pre-assembled before being mounted on the tube 62.
With reference to
Pushing the sleeve 1 towards the tube 62 has the effect that the edge 621 of the tube 62 penetrates into the gap 122 of the head part 12 of the main body 10 of the sleeve 1. The ring 121 of the head part 12 is continuous and closes the edge 621 of the tube 62 which is open due to the slit 64. The opening of the slit 64 is a structural weak point of the tube 62 and, owing to the ring 121, the rigidity of the tube 62 is reestablished, as though no slit were present. However, it is clear that the slit 64 is advantageous for assembly, on the production line, of the sleeve 1 with the tube 62.
Locking of the sleeve 1 to the tube 62 occurs owing to the cooperation between the molding 19 and a slot 629 in the tube 62. When the molding 19, which preferably has a slightly inclined surface 191 so as not to deform the material of the tube 62, penetrates into the slot 629, the tube 62 and the sleeve 1 are joined together integrally. In other words, the sleeve 1 can no longer be extracted from the tube 62 other than by forcing the molding 19 downwards using a tool so that it comes out of the slot 629. Typically this operation is not reversible and the tube (typically metallic) is permanently deformed and/or the sleeve 1 is deformed or breaks.
This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.