US3833962A

US3833962A - Nozzle for vacuum cleaner

Info

Publication number: US3833962A
Application number: US00244806A
Authority: US
Inventors: K Krusche
Original assignee: Allstar Verbrauchsguter GmbH and Co KG
Current assignee: Allstar Verbrauchsguter GmbH and Co KG
Priority date: 1971-05-12
Filing date: 1972-04-17
Publication date: 1974-09-10
Anticipated expiration: 1991-09-10
Also published as: FR2137776A1; JPS5219396B1; ES180291Y; GB1340466A; DE2123436A1; NL7206384A; DE2123436B2; IT955394B; FR2137776B1; SE378351B; AU4214172A; BE783290A; ES180291U; CA1013104A; NL161052B; ZA723191B; CH537179A; AT315119B

Abstract

A nozzle for a vacuum cleaner having a hollow nozzle body having means for connecting the vacuum pipe of a vacuum cleaner to the nozzle body, the nozzle body having a vacuum pick-up opening in a side thereof which is turned away from the connecting means, the part of the opening in the side of the nozzle body being closed by an insert the outer area of which is covered by a brush cover. The insert may either be installed as a part removable from the nozzle body or as a permanent part thereof. In certain of the disclosed embodiments the bristles of the brush cover are tilted with respect to the main extent of the brush cover. The bristles may all be pointed in the same direction, as for example, in the pull direction of the vacuum nozzle. In another illustrative embodiment, a part of the bristles may be tilted in the pull direction and a part may be tilted in the push direction, so that the nozzle picks up lint, dirt and the like in both directions of its travel. The nozzle of the invention may also be pivotally connected with the vacuum pipe of a vacuum cleaner, and may include a pivotally mounted skirt which defines the vacuum area in communication with the vacuum port of the nozzle in all possible positions of tilting of the nozzle about its pivotal connection.

Description

llnited StatesPatent 1191 Krusche 1 Sept. 10, 1974 NOZZLE FOR VACUUM CLEANER I [75] Inventor: Kurt Krusche, Frankfurt/Main,

. Germany [73] Assignee: ALLSTAR Verbrauchsgueter GmbH & Co. KG, Frankfurt/Main, Germany [22] Filed: Apr. 17, 1972 [21] Appl. No.: 244,806

[30] Foreign Application Priority Data May 12, 1971 Germany 2123436 [52] US. Cl. 15/400, 15/231 [51] Int. Cl A471 9/06 [58] Field of Search 15/231, 393, 398, 399, 15/400 [56] References Cited UNITED STATES PATENTS 1,068,713 7/1913 Thurman ..15 /393 2,648,863 8/1953 Darling 15/231 2,793,385 5/1957 Ortega 15/400 X 3,108,310 10/1963 Allen et a1. 15/373 X 3,421,171 l/1969 Tsuruzawa 15/231 UX 3,619,846 11/1971 Krusche et a1...... 15/231 UX Primary Egcgm iner-l-larvey l-lornsby Assistant Examiner-C. K. Moore [5 7] ABSTRACT A nozzle for a vacuum cleaner having a hollow nozzle body having means for connecting the vacuum pipe of a vacuum cleaner to the nozzle body, the nozzle body having a vacuum pick-up opening in a side thereof which is turned away from the connecting means, the part of the opening in the side of the nozzle body being closed .by an insert the outer area of which is covered by a brush cover. The insert may either be installed as a part removable from the nozzle body or as a permanent part thereof. In certain of the disclosed embodiments the bristles of the brush cover are tilted with respect to the main extent of the brush cover. The bristles may all be pointed in the same direction, as for example, in the pull direction of the vacuum nozzle. In another illustrative embodiment, a part of the bristles may be tilted in the pull direction and a part may be tilted in the push direction, so that the nozzle picks up lint, dirt and the like in both directions of its travel. The nozzle of the invention may also be pivotally connected with the vacuum pipe of a vacuum cleaner, and may include a pivotally mounted skirt which defines the vacuum area in communication with the vacuum port of the nozzle in all possible positions of tilting of the nozzle about its pivotal connection.

9 Claims, 14 Drawing Figures PAIENTED SEP 1 0 1914 saw a or 7 Pmmmsmmm 3333.962, SHEET ME 7 FIG. 6 g

FIG.7 I

PATENTEDSEF 1 01914 sum 80$ 7 v NOZZLE FOR VACUUM CLEANER This invention relates to a nozzle for a vacuum cleaner; more particularly it relates to a nozzle of the type indicated provided with an insertprovided' with an outer surface in the form of a brush.

Nozzles which serve as supplemental cleaning tools for vacuum cleaners and which are adapted to be connected to the vacuum pipe of the cleaner are known to the art. Such nozzles have a connecting piece such as a sleeve adapted to be joined to the suction pipe of the cleaner, such connecting piece being joined to a body having an opening in one side thereof forming a nozzle. Such nozzles, which have either a wide or a thin nozzle opening, perform very well in gathering loose dirt and dust particles. They do not, however, perform well in removing fine threads, lint, or the like from a carpet.

This invention has among its objects the provision of a nozzle for vacuum cleaners which not only removes loose dirt particles without difficulty, but also removes small and fine foreign objects and lint that adhere to textile surfaces, as for example, a carpet, upholstery, and the like.

This object is achieved by a nozzle for vacuum cleaners that includes a connecting piece for connection. to a vacuum pipe and a nozzle body connected to. the connecting piece, such body having a side that is turned away from the connecting piece, is open, a part of the open side of the nozzle body being closed by means of an insert, the outer surface of which is covered with a brush. Such insert can be removable, or it may be firmly affixed to the nozzle body. Such brush is advantageously made out of a flat, flexible holder, like a textile fabric orthe like, in which short bristles are arranged close to one another. Advantageously, these bristles are all tilted or pointed in the same direction. The best results can be obtained with such a brush if the nozzle insert is so made and installed that the bristles all point in the direction of pulling of the nozzle as it is applied, for example, to a rug, an upholstered chair, or the like.

The connecting piece can be integral with the nozzle body or it can be so connected thereto as to be firmly or detachably mounted on the nozzle body. In order to increase the efficiency of the nozzle and in order to be able to hold it in the best vacuuming position, the connecting piece may be built in the form of a rotating joint; alternatively, the active components of the connecting piece may be so constructed as to tilt the brush, the nozzle having a movable flap or shutter which is so constructed that it limits the vacuum area or the width of the vacuum slit of the nozzle appropriately for every degree of tilt of the nozzle.

The accompanying drawings, which form a part of the disclosure of the brush of the invention, show a number of non-limiting illustrative embodiments of nozzles in accordance with the invention.

In the drawings:

FIG. I is a view in side elevation of a nozzle with an exchangeable insert;

FIG. 2 is a view in bottom plan of a nozzle with an elongated insert fitted to the nozzle body;

FIG. 2a (sheet 7 of the drawings) is a view in bottom plan of a nozzle with a different shape of nozzle insert;

FIG. 3 is a view in top plan of the nozzle shown in FIG. 1;

FIG. 4 is a view in central vertical section through the nozzle shown in FIG. I, the section being taken along the line CC of FIG. 6;

FIG. 5 is a fragmentary view in section through the brush of FIG. 4, the section being taken along the line 'D*D- of that Figure;

FIG. 6 is a view in vertical section taken along the line AA of FIG. 4;

FIG. 7 is a view in horizontal section taken along the line B-B of FIG. 6;

' FIG. 8 is a view in side elevation ofa further embodiment of nozzle in accordance with the invention. such nozzle having a firmly attached brush insert;

FIG. 9is a view in central vertical section taken in a manner similar to the section of FIG. 4 through the nozzle of FIG. 8;

FIG. 10 is a view in side elevation of a still further embodiment of nozzle, such nozzle being provided with a detachable connecting piece;

FIG. 11 is a view in side elevation of a nozzle with a rotating connecting piece;

FIG. 12 is a view in side elevation of a nozzle provided with a flap to limit the vacuum area and with a vacuum slit at an arbitrary tilt of the nozzle body; and

FIG. 13 is a view similar to that of FIG. 12 which is provided with a shutterrather than a flap as in the embodiment of FIG. 12.

In FIGS. 13, inclusive, there is shown a basic form of the nozzle according to the invention. Such nozzle,

which corresponds basically to the already known auxiliary nozzles for vacuum cleaners, is provided with an inclined connecting piece 2 which is joined to an elongated, relatively'wide nozzle body 3. A nozzle insert 4' is mounted in the nozzle body, the insert being preferably covered with a flat brush cover 5' by means of which dirt particles are disengaged from the area being cleaned, the particles then beingvacuumed. The insert 4 in this embodiment is a part of the open side of the nozzle body which lies opposite the connecting piece 2.

The insert can be mounted in the nozzle body so as to either be removable therefrom or to be permanently attached thereto. In either case, the basic form of the nozzle body is the same.

In FIGS. l-7, inclusive, of the drawing the nozzle 1 is shown in the various embodiments with an exchangeable insert 4. The nozzle insert 4 is in the form of a framed brush component, which can be easily removed from and replaced upon the nozzle body. A flat, flexible holder made, for example, out of a textile fabric or the like which is covered with bristles forms the brush cover 5.- This brush cover, which is supported upon an elastic upholstery liner, is placed on the bottom surface of the floor plate 6 of a cup-like body. The upper edge 7 of the entire circumference of the sidewall is toothed. The edge section of the brush cover 5 is put around the elevated toothed edge 7 of the cupshaped body. From above, that is to say, opposite the brush cover, an upper part 8 that is in the form of a cap is disposed with its side walls surrounding the elevated edge 7 of the floor plate 6 to press downwardly the edge section of the brush cover 5 which overlies edge 7. On the inner side of the side walls of the part 8 there are provided ribs 9 which are staggered in relation to the teeth of the edge 7 of the floor plate 6. After the mounting of the upper, lid part 8, these ribs 9 fit into the gaps of the teeth at the toothed edge 7 and grip the edge section of the brush cover 5 that lies in between such parts. In this manner, brush cover 5, floor plate 6, and the upper part 8 of the insert 4 are firmly connected.

The floor plate which is covered with the brush cover may also be connected firmly with the upper part of the insert, as for example, with some kind of interlocking clamping parts15 and 16 (FIG. 6) or the like that are generally known in the art. These also serve the function of stiffening the insert.

The middle piece of the upper side of the upper, lid part 8, is retained by means of a latch means 10. In the embodiment shown, the basic form of this latch 10 is a long, rectangle. Of course, it can have any other shape as well. The latch means 10 is secured removably in the space 12 in the upper side of the nozzle body 3. An advantageous removable connection can be achieved by means of engaging notchings and projections on the respective parts. An example of this is shown in FIGS. 4 and 7. In the middle of the opposing widths of the latch means 10, a wedge-shaped notching 11 is provided from the outside. The space 12 in the upper side of the nozzle body 3 is limited by side walls 13 that extend downwardly. At the open end of these side walls 13, corresponding to the notchings 11, there are provided projections on the inner side, that is, opposing each other, also preferably wedge-shaped. The downwardly projecting side walls 13 are slightly elastic, so that they are pressed somewhat to the outside when the latch means 10 is being inserted, whereby the projections 14 slide along the outer side of the long shaped walls of the latch means 10. As soon as the projections 14 have reached the notchings 11, they lock with them and lock the nozzle insert 4 in the nozzle body 3. By means of pressure from above on the latch means 10, the elastic side walls 13 are sprung apart from each other by the slope of the wedge-shaped notchings 11; the projections 14 slide out'of the notchings and release the insert 4. Of course, other removable connections are possible.

A simpler embodiment is shown in FIGS. 8 and 9 in which the insert 4a is built into the nozzle body 3a. Here there is no upper part of the insert that is shaped as a lid and also no latching means. The brush cover 5a which is placed upon the floor plate 6a is held by means of the lid-shaped nozzle body 3a. The assembly thus basically corresponds to the one with the exchangeable insert 4. The brush cover 5a which is supported by an elastic upholstery liner, or which is lined, has its edge section placed around the elevated edge 7a of the floor plate 6a and over the toothed fringe of the edge 7a. The nozzle body 3a is shaped on the side opposing the brush cover 5a in such a way that the sides S, S which are tilted downwards like lids, surround the elevated edge 7a of the floor plate 6a and thus surround the edge section of the brush cover 5a that lies in between. From the inner side of the side walls S, S there project thin ripples 9a which point inwardly. These ripples are staggered in relation to the teeth of the toothed edge of the floor plate 6a. When the nozzle body 3a is placed on the floor plate, the ripples 9a interlock with the tooth spaces at the toothed edge and clamp the edge section of the brush cover. In this manner, the insert 4a and the nozzle body 3a form a unit.

By means of this manner of clamping, in the exchangeable version, and also in the firmly built-in insert, there is no necessity for any screwing together or adhesion of the parts that are to be connected with each other, so that the assembly of the parts may be performed fully automatically and thus very economically.

It is desired to point out that this clamping can be satisfactorily obtained in an even simpler way (not shown), and also fully automatically. Here the elevated edge of the floor plate 6 or 6a ends in a sharp edge, which points up vertically or is slightly pointed outwards. Around the outer side of the elevated edge of the floor plate and also around the sharp edge of it there is placed the edge section of the brush cover, the floor plate also being provided preferably with the resilient support or lined upholstery, as in the case above. When assembling the lid-shaped part of the exchangeable insert 9 or of the lid-shaped nozzle body, its side parts surround the edge section of the brush cover, and its upper side presses the brush cover from above onto the sharp edge and clamps it firmly.

The

insert

4 or 4a in the embodiments shown preferably occupies the whole width of the front area of the open side of the

nozzle body

3 or 3a. Behind the insert there is the vacuum area or

vacuum part

17, or 17a, which leads into the vacuum opening of the connecting

piece

2, 2a. The connecting piece is connected to a vacuum pipe (not shown) of the vacuum cleaner. By sliding the nozzle to and fro, the dirt particles which are loosened or disengaged by the brush cover are then removed by vacuum.

The nozzle, according to the invention, is especially suitable for a brush cover made out of a Hat, flexible holder, which is covered with bristles that are arranged close to each other and which are all tilted in the same direction. The direction of tilting of the bristles extends at an angle to the vertical axis of the insert and the tips point towards the vacuum port, that is, in the direction of pulling of the nozzle, which is determined by the tilted connecting piece. When the vacuum cleaner or the vacuum pipe is being pulled with the nozzle, the bristles also collect the finest dirt particles and foreign objects that are sticking to the ground and sweep them into bristle spaces of the brush cover of the nozzle insert. As soon as the nozzle is pushed, all the collected foreign bodies and dirt particles are released from the spaces in between the bristles and emerge, in a loosened condition, immediately in front of the vacuum area or the

vacuum port

17, 17a, where they are swiftly vacuumed into the vacuum opening of the connecting piece. In this way, one can obtain, by easy pulling and pushing of the vacuum cleaner with the connected nozzle, an optimal cleaning of carpets, upholstery, blankets, wall-hangings and the like. In such construction, the brush cover hereby cleans itself again and again.

In a nozzle insert which is equipped with such tilted bristles on a brush cover, other possible and advantageous embodiments of this insert are possible. It can, for example, envelope the entire nozzle opening and can have in its middle an elongated vacuum port (FIG. 2a). The

brush cover

5 and 5a is arranged either around or along the two longitudinal axial sides of the vacuum port 17 either in one line or in divided strips. The bristles of the brush cover are preferably tilted with their tips towards the vacuum port 17. In this manner, the dirt particles are taken up both when pulling and pushing the nozzle and are again released, as in the two different movements one part of the bristle tips of the brush cover are always pointed for reception (taking up) of dirt and another part of the same are pointed for releasing dirt. The optimal vacuum procedure thus is obtained with each and every movement of the nozzle. Such a nozzle insert can be built either in an exchangeable version of it can be permanently built-in.

FIG. shows a changed embodiment of the nozzle itself. Such nozzle consists of a nozzle body 18 with a firmly installed insert 19. In the back part of the nozzle body its upper side is provided with a space member 20, which is aligned with the vacuum area or the vacuum port 21. The space member 20 is built so that it fits onto a nozzle 22 which is connected to the vacuum pipe. Such nozzles, that basically. have the same form as a connecting piece of the above-mentioned sort, are known and are sold in different shapes as additional parts for vacuum cleaners.

One can easily vacuum and clean reachable areas with a connecting piece that is rigidly affixed to a nozzle body. But, if the nozzle is to be moved under fumiture, like cabinets, easy chairs, couches, and the like, in order to vacuum under them, it cannot be done with an inflexible nozzle. Mostly the vacuum pipe and the connecting piece are too high, so that-both have to be lowered to a high degree, that is to say, both have to be moved towards the floor. Thus, however, a rigidly affixed nozzle and thus also the brush cover is tilted upwards by rotation, and the effective area is elevated out of contact with the area that is to be cleaned. In order to avoid this disadvantage, the nozzle body can be flexibly affixed in relation to the connecting piece. The known flap hinges, however, are not suitable for. nozzles that have an insert which is covered with a brush cover.

When pushing the nozzle forward, the friction of the rough area of the brush cover on the rough area of the texture to be cleaned, for example, a carpet, is so great that the nozzle tilts towards the flap hinge. The embodiment of FIG. 11, which incorporates a rotating joint between the nozzle and the connecting piece, overcomes this disadvantage. This embodiment is shown with an exchangeable, removable insert. Of course, here also the insert can be firmly built-in. The nozzle body 23 is a closedin compartment whose back wall 24 runs basically vertically. In the upper section of this back wall, a round opening is provided, in which fits the front part of the axle-shaped connecting piece 25. This front part is inserted in such a manner into the opening that it cannot be moved horizontally, but is easily turnable through 360. In this manner, the vacuum pipe (not shown) can be rotated with the connecting piece 25, while the nozzle body 23 does not this turning movement relative to the floor. In order to push the nozzle under a couch or the like, the vacuum pipe together with the connecting piece 25, for example, has to be turned through 90 so that this connecting piece lies about in the same plane as the upper side of the nozzle body 23. The effective area of the insert always remains in contact with the area that is to be cleaned.

A different embodiment, in which the nozzle can be used in different positions, is shown in FIG. 12. Here the nozzle body 26 is rigidly connected to the connecting piece. The brush cover, which is covered with insert 28, is shown rounded to the outside, so that, each time the connecting piece 27 tilts down, a part of the effective area of the brush cover touches the area to be cleaned. If, however, the connecting piece 27 in such anozzle is elevated, thus enlarging the angle between it and the area to be cleaned, the vacuum area, that is to say, the vacuum port 29 is enlarged and the vacuum pull no longer concentrates on the desired area.

To eliminate this disadvantage, the nozzle is equipped with a skirt 30, which defines the vacuum area communicating with the vacuum port 29 at every desired tilted position of the nozzle. This skirt 30 is made out of a frame that is limited on its sides, and whose side walls 31 are slightly flared out from the back side to the front side, while its back wall 32 is rectangular. Preferably this back wall 32 is slightly tilted and it corresponds to the back wall 26a of the nozzle body 26. The lower edge 31a of each

side wall

31, 31 runs in a bow or arch corresponding to the insert 28. Each side wall of the skirt 30 is bored at its front side and, for example, is connected by a screw 33 with the side walls 31 of the nozzle body 26. This connection, however, is not rigid but the aligned screws form a turning axle around which the skirt 30 is turnable or pivotable. The area for this turning movement is sufiiciently large so that the skirt 30 can be moved by its gravity when elevating the nozzle, so that the lower edges 31a of the side walls 31 as well as the lower edge of the back wall 32 of this skirt always lie on the floor. Thus the vacuum area connected to vacuum port 29 is limited on all sides by the side walls 31a and backwall 32 of the skirt 30, as shown in FIG. 12; the vacuum efficiency of the vacuum cleaner is thus concentrated. The skirt 30 adjoining the inner sides of the nozzle body or the outer sides of the nozzle body can be arranged in an envelop ing manner. Instead of the screws 33, a different advantageous pivot connection can be provided.

Instead of the skirt 30, for example, a seesaw-shaped shutter 34 can be used, as is shown in FIG. 13. The nozzle is provided with a connecting piece 27 and a nozzle body 26 with an insert, the effective area of which is tilted to the outside as in FIG. 12. The shutter 34 envelopes at all sides the side parts of the nozzle body 26. with a small working space or play. I

The front side and rear side V and R of the nozzle body and thus the front side and rear side of the shutter 34 are preferably slightly tilted, so that an opposingangular movement of these adjoining walls can be achieved without disturbance, as indicated with the arrow P. The shutter 34 and the nozzle are pivotable at the elongated sides by a turning point that is situated in the middle. The advantage of such a seesaw-shaped shutter 34 is that it cannot get stuck in any position. By means of its form and method of hanging, it has to be held to the floor with its lower edge 340, so that in every position of the nozzle during the vacuuming procedure, it limits the vacuum area connected to the vac- ,uum port 29' at all sides, in whatever position it ma Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such plurality of embodiments, but is capable of numerous modification within the scope of the appended claims. I

What is claimed is:

l. A nozzle for a vacuum cleaner, comprising a hollow nozzle body having means for connecting the vacuum pipe of a vacuum cleaner thereto, a side of the nozzle body which is turned away from the vacuum pipe connecting means having an opening therein, and an insert in the nozzle body closing a portion of such opening, said insert having a transverse bottom plate and upstanding side walls, the outer area of the insert being covered with a brush cover which extends across the bottom plate outwardly thereof and up along the side walls and a lid-shaped upper part clamping the brush cover downwardly upon the upper edge of the side walls of said insert, wherein said insert has a cupshaped body and the upper edges of the side walls have a plurality of sawtooth projections, and the lid-shaped upper part has a downwardly extending skirt which has a plurality of projections so as to interdigitate with the projections on the side walls and to clamp the edges of the brush between said skirt and said side walls.

2. A nozzle according to claim 1, wherein the insert is installed so as to be removable from the nozzle body.

3. A nozzle according to claim 1, wherein said projections on said skirt comprise a plurality of thin radially inwardly-directed ribs on the inner surface of the skirt, said ribs extending parallel to the axis of the skirt and being spaced so that when the lid-shaped upper part is assembled on the insert with the upstanding edge portions of the brush cover therebetween, the ribs on the skirt and the saw-tooth projections on the upper edge of the side walls of the body are interdigitated and clamp the brush cover therebetween.

4. A nozzle according to claim 1, wherein the lidshaped upper part forms part of the insert and comprises an upstanding central stem which is received within a critical passage in the body of the nozzle, and comprising interfitting locking formations on said stem and the wall of the passage whereby to hold the insert in place.

5. A nozzle according to claim 4, wherein the passage extends through the upper surface of the body, and the upper end of the stem extends upwardly through the passage to be exposed in the form of a button protruding upwardly from the body of the nozzle.

6. A nozzle according to claim 4, wherein the interlocking formations comprise radially inwardly generally wedge-shaped projections on the inner wall of the passage through the body of the nozzle, and generally similarly shaped radially outwardly open seats in the wall of the stem which receive such projections.

7. A nozzle according to claim 1, wherein the insert covers the entire area of the opening in the nozzle body at the front thereof, and comprising a nozzle port in the nozzle body behind the. insert, said nozzle port being connected to the means for connecting a vacuum pipe to the nozzle body.

8. A nozzle according to claim 1, wherein the brush cover includes a resilient liner underlying the portion of the brush cover which lies outwardly exposed, the brush having a plurality of closely-spaced short bristles which are all pointed in the same direction and are tilted in a direction which is disposed at an angle to the longitudinal axis of the insert.

9. A nozzle according to claim 8, wherein the insert covers the entire area of the opening in the nozzle body at the front thereof, and comprising a nozzle port in the nozzle body behind the insert, said nozzle port being connected to the means for connecting a vacuum pipe to the nozzle body; and wherein the insert is installed in the body of the nozzle in such manner that the tips of the bristles of the brush cover point in the direction of the vacuum port in the direction of pulling of the vacuum nozzle in USE.

Claims

1. A nozzle for a vacuum cleaner, comprising a hollow nozzle body having means for connecting the vacuum pipe of a vacuum cleaner thereto, a side of the nozzle body which is turned away from the vacuum pipe connecting means having an opening therein, and an insert in the nozzle body closing a portion of such opening, said insert having a transverse bottom plate and upstanding side walls, the outer area of the insert being covered with a brush cover which extends across the bottom plate outwardly thereof and up along the side walls and a lid-shaped upper part clamping the brush cover downwardly upon the upper edge of the side walls of said insert, wherein said insert has a cup-shaped body and the upper edges of the side walls have a plurality of sawtooth projections, and the lid-shaped upper part has a downwardly extending skirt which has a plurality of projections so as to interdigitate with the projections on the side walls and to clamp the edges of the brush between said skirt and said side walls.

4. A nozzle according to claim 1, wherein the lid-shaped upper part forms part of the insert and comprises an upstanding central stem which is received within a critical passage in the body of the nozzle, and comprising interfitting locking formations on said stem and the wall of the passage whereby to hold the insert in place.

7. A nozzle according to claim 1, wherein the insert covers the entire area of the opening in the nozzle body at the front thereof, and comprising a nozzle port in the nozzle body behind the insert, said nozzle port being connected to the means for connecting a vacuum pipe to the nozzle body.