GB2161902A

GB2161902A - Non-return flap valve for vacuum cleaner

Info

Publication number: GB2161902A
Application number: GB08516288A
Authority: GB
Inventors: Alain Verdier; Marc Polly
Original assignee: Black and Decker Inc
Current assignee: Black and Decker Inc
Priority date: 1984-07-18
Filing date: 1985-06-27
Publication date: 1986-01-22
Also published as: IT8521499A0; FR2567744A1; DE8519055U1; GB8516288D0; GB2161902B; FR2567744B1; IT1185213B

Abstract

A non-return flap valve for a vacuum cleaner has a movable sealing flap (10) and a mounting part (20) having sleeves (21) for mounting the non-return flap valve (10) inside a nozzle body (1) of the vacuum cleaner. One or more strips (30) connect the flap (10) to and space it from the mounting part (20). A constriction in thickness, such as a groove (31), across each strip (30) defines and extends along a flexing axis about which the flap (10) pivots relative to the mounting part (20). Preferably, the flap, the mounting part, and the strips are integrally formed. The flap (10) and the mounting part (20) may each be substantially rigid. <IMAGE>

Description

SPECIFICATION Non-return flap valve for vacuum cleaner FIELD OF THE INVENTION The present invention relates to a non-return flap valve for the nozzle of a vacuum cleaner, in particular a miniature hand vacuum cleaner, as well as a vacuum cleaner of this kind.

BACKGROUND OF THE INVENTION Such a miniature hand vacuum cleaner is described, in particular, in European patent number 0,008,11 7, in which the suction noz- zle is formed by the front part of the collecting chamber of the appliance. To prevent the dust and debris accumulated in this chamber from escaping when the appliance is switched off, provision is made for a non-return flap valve which seals this nozzle.

Figs. 1 and 2 show such a device of the prior art: the nozzle 1 comprises a suction channel 2 which has at its end an internal flange 3 on the periphery of which rests a sealing flap 4 which is connected to the body of the nozzle inside the latter. As a result of the partial vacuum created by the vacuum cleaner, the flap is able to move between a closed position (reference numeral 4) and an open position (reference numeral 4'). In the closed position, the flap forms a good-closure with the flange 3.

Until now, this sealing flap had been made from a shaped piece of flexible material (such as rubberized cloth with a substantially isotropic structure) which rests against the internal flange 3, is fixed to the nozzle body by insertion onto pins 5 and locked in position by means of eyelets 6 (visible in Fig. 2). Preferably, as disclosed in German patent 1,628,707, the plane defined by the peripheral flange 3 is slightly inclined (by an angle designated 8 in Fig. 1) with respect to the plane against which the eyelets 6 rest. In this way, when at rest, the shaped piece of flexible material forming the flap is slightly flexed and thus improves the tightness of the flap valve in the closed position.

This type of flap valve, despite the advantage of its simplicity, has proved to possess a number of drawbacks when used.

In particular, after prolonged use, permanent deformation of the flap can be noted, due to ageing of the rubberized cloth. This results not only in the flap being applied less weakly against the flange (the above mentioned flexing effect being reduced), but also in a loss of flatness of the flap: the latter tends to warp slightly with time and no longer forms a good closure with the internal flange of the nozzle.

Furthermore, on account of the flexibility of the material, debris or dust can accumulate in the vicinity of the eyelets between the upper region of the flange and the flap and is kept there because of the flexible nature of the rubberized cloth. This results, therefore, in a permanent loss of tightness in this area.

Finally, positioned and insertion of the eyelets constitute a delicate operation on account of the poor accessibility of the pins which are mounted right at the back of the vacuum cleaner chamber and in the narrowest part of the latter.

SUMMARY OF THE INVENTION The object of at least preferred embodiments of the present invention is to provide an improved flap valve for a vacuum cleaner which mitigates or overcomes the above drawbacks.

Accordingly, therefore, the invention provides a non-return flap valve for a vacuum cleaner, comprising a movable sealing flap, a stationary part having means for mounting the non-return flap valve in a nozzle body of the vacuum cleaner, a strip connecting said flap to said stationary part and spacing said flap from said stationary part, and a constriction iri thickness across said strip, said constriction defining and extending along a flexing axis about which said flap articulates relative to said stationary part.

Advantageously, the flap (and the stationary part) may be substantially rigid.

In this way, the flap is articulated with respect to the mounting means, around the flexing axis formed by the hinge, so as to pivot with a single degree of freedom.

Preferably, the flap, the strip, and the mounting means are integrally formed as a single piece assembly.

The expression "substantially rigid" means that the shape given to the part forming the flap (generally a flat shape) remains constant during the course of time and unaffected by external stresses, unlike the shaped piece of rubberized cloth (which, if it were rigid, would prevent opening of the flap valve altogether).

In the structure according to the invention, however, opening of the flap is ensured merely by the strip or a plurality of such strips.

Due to the non-warping feature of the preferred flap, the resistance to ageing is improved considerably compared with the flap of the prior art; moreover, debris is unable to accumulate between the flap and the internal flange since the flap is not inherently flexible enough to retain this debris.

Preferably, each strip of material has, over its entire width, a constriction in thickness, for example a constriction in the form of a groove with a cylindrical surface.

Preferably, also, a plurality of strips is provided, whose respective constrictions are rectilinear and aligned.

Moreover, advantageously, the mounting means comprises at least one sleeve for co operating with a matching pin which is integral with the nozzle body.

The flap valve can therefore be fixed very simply by pushing it onto the pins, without having to use eyelets in order to keep the flap valve in place. Thus, unlike the prior art, it is possible to avoid the use of additional fixing pieces, which are also difficult to position and secure.

To this end, advantageously, the flexibility of the sleeve is greater than that of the material forming the pin so as to permit forcefitting of the sleeve onto the pin, to keep the flap valve in place on the nozzle body.

The mounting means may comprise a plurality of sleeves which are connected together by a common stiffening element. This feature enables the double advantage of making the sleeves integral with one another (which simplifies positioning of the flap valve during mounting, the sleeves being arranged at intervals and aligned), and of preventing possible deformations of the flap when acted upon by stresses which tend to deform it with respect to its original shape (generally a flat shape).

Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiment, the appended claims and the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawing: Figure 1, mentioned above, is a section, along the line I-I of Fig. 2, of a nozzle and a flap valve of the prior art; Figure 2, also mentioned above, is a section along the line ll-ll of Fig. 1; Figure 3 is a plan view of a flap valve according to the invention; Figures 4 and 5 are sections of the flap valve of Fig. 3 on the lines IV-IV and V-V, respectively, of Fig. 3; Figure 6 shows the detail within the circle designated VI in Fig. 5; and Figure 7 is a similar view to Fig. 1, but showing a flap valve according to the invention.

DETAILED DESCR!PTION OF THE PREFERRED EMBODIMENTS The preferred embodiment of the invention is shown in Figs. 3 to 7.

In Fig. 3, a movable sealing flap 10, which has a flat shape, is connected to a stationary part 20 by strips of material 30, of which there are three for example. The stationary part 20 comprises a plurality of parallel sleeves 21, 22, for example two, which are connected together by a rib-like stiffening ete- ment 23. As can be appreciated from Figs. 4 and 7, the sleeves 21, 22 have a slightly conical shape, and the entrance portion 35 of each sleeve adjacent the flap 10 is tapered to facilitate the sleeves 21, 22 being force-fitted onto the pins 5. The pins 5 are integral with the extend rearwardly into the nozzle body (see Fig. 7). The material forming the singlepiece flap valve is chosen so as to have a greater flexibility than that of the pins 5 to permit precisely this force-fitting operation and avoid the use of an additional part to ensure securing.The flap 10 and the stationary part 20 thus form two essentially rigid elements which are articulated so as to pivot about the flexing axis of the hinge formed by the strips 30. This structure allows pivoting with a single degree of freedom, unlike the rubberized-cloth sealing flaps of the prior art, which were deformable in all directions.

Fig. 6 shows a detail of this hinge; each strip of material 30 has a groove 31 of cylindrical shape, so as to form a constriction 32 which improves the flexibility of the part in this area. The respective dimensions of the groove 31 and of the constriction 32 are chosen, in accordance with the physical characteristics of the material, so as to achieve a desirable balance between too great a rigidity (which would prevent the flap from opening sufficiently under the effect of the partial vacuum created by the motor driven fan of the vacuum cleaner) and too great a flexibility (which would not ensure a sufficient degree of tightness in the closed position). The constrictions 32 of the plurality of strips 30 define and extend along the flexing axis of the flap 10.The constrictions 32 are preferably all on the same side of the flap 10 adjacent the junction between the respective strip 30 and the flap 10. The constrictions 32 may be formed on the rib 23 side of the flap 10, i.e.

in the opposite side of the strips 30 to that shown in Figs. 4 and 6.

To improve the tightness of the closure despite the very flexible hinges, it is possible, as disclosed in German patent 1,628,707 mentioned above, to flex slightly the hinge in the closed position, by inclining at an angle H (see Fig. 7) the plane of the flange 3 against which the flap rests and the plane perpendicular to the pins 5 (and therefore to the sleeves 21 and 22). Also, the flap 10 may be permanently inclined at an acute angle to a plane containing the axes of the sleeves 21, 22, somewhat in the orientation shown in Fig. 7.

As can be appreciated from Fig. 4, the stiffening rib 23 extends rearwardly from the flap 10 in a plane transverse to the plane of the flap 10, the parallel axes of the sleeves 21, 22 substantially lying in the plane of the stiffening rib 23. Also, the spaced apart strips 30 space the flap 10 from the stationary part 20 as can be seen in Fig. 3.

The above described embodiments, of course, are not to be construed as limiting the breadth of the present invention. Modifications, and other alternative constructions, will be apparent which are within the spirit and scope of the invention as defined in the

Claims

appended claims. CLAIMS

1. A non-return flap valve for a vacuum cleaner, comprising: a movable sealing flap; a stationary part having means for mounting the non-return flap valve in a nozzle body of the vacuum cleaner; a strip connecting said flap to said stationary part and spacing said flap from said stationary part; and a constriction in thickness across said strip, said constriction defining and extending along a flexing axis about which said flap articulates relative to said stationary part.

2. The non-return flap valve of Claim 1, wherein said flap, said stationary part, and said strip are integrally formed.

3. The non-return flap valve of Claim 1 or 2, wherein said constriction is adjacent the junction of said strip and said flap.

4. The non-return flap valve of any preceding claim, wherein said constriction is formed by a groove in said strip.

5. The non-return flap valve of any preceding claim, having a plurality of spaced apart strips connecting said flap to said stationary part, each strip having a said constriction extending along said flexing axis.

6. The non-return flap valve of any preceding claim, wherein said mounting means comprises a sleeve adapted to be forced fitted onto a pin in said nozzle body.

7. The non-return flap valve of Claim 6, wherein said sleeve extends transversely away from said flap and an entrance of said sleeve adjacent said flap is tapered to facilitate force fitting of said sleeve onto said pin.

8. The non-return flap valve of any one of Claims 1 to 5, wherein said stationary part comprises a stiffening element and said mounting means comprises a plurality of sleeves connected together by said stiffening element.

9. The non-return flap valve of Claim 8, wherein said stiffening element comprises a flat rib extending in a plane transverse to said flap, said sleeves have parallel axes disposed in said plane, each said strip extends from said rib in a direction transverse to said plane, and said flexing axis is parallel to but spaced from said plane.

10. The non-return flap valve of any preceding claim, wherein said flap and said stationary part are each substantially rigid.

11. A vacuum cleaner having a nozzle body inside which is mounted the non-return flap valve as claimed in any preceding claim.

12. A non-return flap valve for a vacuum cleaner substantially as hereinbefore described with reference to Figs. 3 to 7 of the accompanying drawing.

13. A vacuum cleaner substantially as hereinbefore described with reference to Fig.

7 of the accompanying drawing.