EP1106133A1

EP1106133A1 - Telescopic vacuum cleaner suction pipe

Info

Publication number: EP1106133A1
Application number: EP99123985A
Authority: EP
Inventors: Pangeng Shen
Original assignee: Wuxian Yuexi Power Cable and Electrical Factory
Current assignee: Wuxian Yuexi Power Cable and Electrical Factory
Priority date: 1999-12-07
Filing date: 1999-12-07
Publication date: 2001-06-13

Abstract

The telescopic vacuum cleaner suction pipe according to the present invention is characterised by an adjustment means for adjustment of the length of the telescopic suction pipe which is adjustable to an arbitrary length and which is of a simple construction and easy to operate.

The adjustment means comprises a first clamping element (4) being attached at one end of said outer pipe (1) and having a conical inner surface (13) tapering towards the end opposite to said outer pipe and a second clamping element (5) axially adjacent to said first clamping element (4) and having an inner diameter being slightly greater than the outer diameter (d2) of said inner pipe (6) and a conical outer surface (14) tapering towards its end opposing said first clamping element (4), wherein said second clamping element (5) is axially movable in the direction towards said first clamping element (4) whereby said conical inner surface (13) and said conical outer surface (14) are overlapping each other and an inner surface (15) of said second clamping element (5) is pressed against an outer surface of said inner pipe (6) to clamp said inner pipe (6) in the respective axial position relative to said outer pipe.

Description

BACKGROUND OF THE INVENTION

The present invention generally relates to telescopic vacuum cleaner suction pipes, and more particularly to a telescopic vacuum cleaner suction pipe as defined in claim 1.
Conventional suction pipes for vacuum cleaners comprise an outer pipe and an inner pipe having an outer diameter smaller than the inner diameter of said outer pipe wherein said inner pipe is axially slidable within the outer pipe, i.e. a telescopic suction pipe, to adjust the length of the suction pipe. Those telescopic suction pipes conventionally include an adjustment mechanism to adjust the length of the suction pipe.
In, for example, DE 299 09 219 U1 and DE 299 09 221 U1 there are disclosed telescopic vacuum cleaner suction pipes comprising a special adjustment mechanism to adjust the length of the suction pipe. The adjustment mechanism includes an axially extending locking strip provided on the inner pipe and a locking means being movable along the longitudinal axis of the suction pipe and comprising at least one locking surface. For adjustment of the inner pipe relative to the outer pipe the at least one locking surface engages with locking countersurfaces provided in locking recesses of the locking strip. For changing the length of the suction pipe the locking surface is released from the locking countersurface and the inner pipe is slided within the outer pipe. A similar adjustment mechanism is further disclosed in EP 0 552 481 B1.
However, the known adjustment mechanisms used in conventional telescopic vacuum cleaner suction pipes do only provide an adjustment of the length of the suction pipe in predefined steps, wherein these steps are defined by the usually evenly spaced apart locking recesses of the locking strip provided on the inner pipe.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a telescopic suction pipe for vacuum cleaners which is adjustable to an arbitrary length by means of a simply constructed and easy to operate adjustment means.
This object is achieved by a telescopic vacuum cleaner suction pipe comprising an outer pipe, an inner pipe having an outer diameter smaller than the inner diameter of the outer pipe wherein the inner pipe is axially slidable within the outer pipe and an adjustment means to adjust the length of the suction pipe, characterised in that the adjustment means comprises a first clamping element being attached at one end of the outer pipe and having a conical inner surface tapering towards the end opposite to the outer pipe and a second clamping element axially adjacent to the first clamping element and having an inner diameter being slightly greater than the outer diameter of the inner pipe and a conical outer surface tapering towards its end opposing the first clamping element, wherein the second clamping element is axially movable in the direction towards the first clamping element whereby the conical inner surface and the conical outer surface are overlapping each other and an inner surface of the second clamping element is pressed against an outer surface of the inner pipe to clamp the inner pipe in the respective axial position relative to the outer pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings, in which:

Fig. 1: is an exploded cross-sectional view of a telescopic vacuum cleaner suction pipe according to the present invention; and
Fig. 2: is a cross-sectional view of the assembled suction pipe of Fig. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A description will now be given of a preferred embodiment of the present invention with reference to Figs. 1 and 2.
The telescopic suction pipe for vacuum cleaners according to the present invention comprises an outer pipe 1 having an inner diameter dl and an inner pipe 6 having an outer diameter d2 which is smaller than the inner diameter dl of the outer pipe 1. Thus the inner pipe 6 is axially slidable within the outer pipe 1, as indicated by an arrow a in Fig. 2. Further, the outer pipe 1 comprises a radially diminished portion (not shown) provided at the end of the outer pipe 1 opposite to the end thereof shown in Figs. 1 and 2. This radially diminished portion has an inner diameter being smaller than the outer diameter d2 of the inner pipe 6 so that the inner pipe 6 may not slide totally through the outer pipe 1 but will stop at the diminished portion of the outer pipe 1.
For the adjustment of the length of the telescopic suction pipe the suction pipe further comprises an adjustment means. This adjustment means includes a first clamping element 4 and a second clamping element 5 which are of an essentially tubular construction. The first clamping element 4 comprises a first outer surface portion 19 having an outer diameter being slightly smaller than the inner diameter dl of the outer pipe 1 so that the outer pipe can be axially slided onto the surface portion 19 of the first clamping element. To define the axial positioning of the outer pipe 1 relative to the first clamping element the outer surface of the first clamping element 4 comprises an annular shoulder 18 serving as a stopping element for the axial movement of the outer pipe. In addition, at least one locking projection 8 is provided on the outer surface portion 19 near the end opposing the outer pipe 1 which is engageable with at least one locking recess 7 being provided in the inner surface of the outer pipe 1. In the engaged state of the locking projections 8 and the locking recesses 7 the first clamping element 4 is attached to the outer pipe 1 in a fixed position. Further, the locking projection 8 of the first clamping element 4 may be provided with a spring element (not shown) to bias the locking projection 8 radially against the inner surface and into the locking recess 7 of the outer pipe 1.
It should be noted that, alternatively, the locking projection 8 may be provided on the inner surface of the outer pipe 1 and the locking recess 7 may be provided on the outer surface of the first clamping element 4 as well.
Further, the first clamping element 4 comprises a conical inner surface 13 provided at the end of the first clamping element being opposite to the outer pipe 1, as can be best seen in Fig. 1. This conical inner surface 13 tapers towards the end side of the first clamping element 4, i.e. the inner diameter of the first clamping element 4 at the end portion thereof is greater than the inner diameter of the first clamping element 4 at the axially center portion thereof Moreover, the inner diameter of the first clamping element 4 along its entire length has to be greater than the outer diameter d2 of the inner tube 6.
In addition, the first clamping element 4 comprises a projection 10 provided on its outer surface and serving as a rotational stopping element for a displacement means 3 and an external thread 12 provided on its outer surface and serving as a connection with an interior thread 11 of the displacement means 3. The displacement means 3 will be described in more detail hereinbelow
The second clamping element 5 of the adjustment means has an inner diameter which is only slightly greater than the outer diameter d2 of the inner pipe 6. However, the inner pipe 6 is still axially slidable through the second clamping element 5 in the released state of second clamping element 5.
In the assembled telescopic suction pipe the second clamping element 5 is arranged axially adjacent to and partially overlapping with the first clamping element 4, as can be best seen from Fig. 2. Therefore, the second clamping element 5 is provided with a conical outer surface 14 at the end of the second clamping element 5 opposing the first clamping element 4. The conical outer surface 14 of the second clamping element 5 tapers towards the end side of the second clamping element 5, i.e. the outer diameter of the second clamping element 5 at the end portion thereof is smaller than the outer diameter of the second clamping element 5 at the axially center portion thereof. Further, the maximum outer diameter of the conical outer surface 14 of the second clamping element 5 is greater than the minimum inner diameter of the conical inner surface 13 of the first clamping element 4 and the minimum outer diameter of the conical outer surface 14 of the second clamping element 5 is smaller than the maximum inner diameter of the conical inner surface 13 of the first clamping element 4 so that the second clamping element 5 may not slide totally through the first clamping element.
At the end of the second clamping element 5 opposite to the conical outer surface 14 the outer surface of the second clamping element 5 is provided with one or more annular grooves 16. The annular projections located axially between these annular grooves 16 are extending radially outward.
Further, the adjustment means comprises a displacement means 3 which is provided for axially moving the second clamping element 5 in the direction to and away from the first clamping element 4.
The displacement means 3 is of an essentially tubular construction the inner diameter thereof being greater than the outer diameters of the outer pipe 1 and the first and second clamping elements 4 and 5. The displacement means 3 is provided with an internal thread 11 extending along a predefined portion in the axial direction and corresponding to the external thread 12 of the first clamping element 4. In the assembled state shown in Fig. 2, the external thread 12 of the first clamping element 4 engages with the internal thread 11 of the displacement means 3. Therefore, the displacement means 3 is rotationally mounted on the first clamping element 4 via the thread connection 11, 12.
To limit the rotational movement of the displacement means 3 in the clockwise direction as well as in the counter-clockwise direction the displacement means 3 comprises an annular projection 9 provided on its inner surface and extending along a predefined circumferential portion of the displacement means 3. In the assembled state of the telescopic suction pipe, the projection 9 of the displacement means 3 and the above-mentioned projection 10 on the outer surface of the first clamping element 4 are located in the same plane in axial direction. Therefore, the projection 10 of the first clamping element 4 functions as a stopping element for the annular projection 9 of the displacement means3 so that the rotational movement of the displacement means 3 around the first clamping element 4 can be limited and the displacement means 3 may not be unintendedly separated from the first clamping element 4.
By rotation of the displacement means 3 around the first clamping element 4 the displacement means 3 also performs an axial displacement relative to the first clamping element 4 and the outer pipe 1. The amount of this axial displacement depends on the angle of rotation as well as the lead of the threads 11, 12. This axial displacement of the displacement means 3 is transferred to an axial displacement of the second clamping element 5 as follows.
The displacement means 3 is provided with one or more annular projections 17 extending radially inwardly from the inner surface of the displacement means 3. These annular projections 17 are axially located at an position where, in the assembled telescopic suction pipe, the annular grooves 16 of the second clamping element 5 are axially located. Further, the axial spacings between the annular projections 17, the widths and the inwardly extensions of the annular projections 17, the axial spacings between the annular grooves 16 and the widths and the outwardly extensions of the annular grooves 16 are selected so that the annular projections 17 and grooves 16 are able to engage with each other. The engagement, however, is preferably achieved without wedging so that on the one hand the telescopic suction pipe is easy to assemble and the displacement means 3 is rotatable in respect to the second clamping element 5.
By the engagement of the annular projections 17 of the displacement means 3 and the annular grooves 16 of the second clamping element 5, the axial displacement of the displacement means 3 due to its rotational movement is transferred to an axial displacement or movement of the second clamping element 5. The amount and direction of the axial movement of the second clamping element 5 correspond to the amount and direction of the axial displacement of the displacement means 3.
The axial movement of the second clamping element 5 in the direction towards the first clamping element 4 causes the conical surfaces 13, 14 of the first and second clamping elements 4, 5 to overlap each other. If a certain amount of overlap is achieved the end of the second clamping element 5 comprising the conical outer surface 14 is pressed inwardly since an outwardly movement of the first clamping element 4 is prevented by the stable displacement means 3 surrounding the first clamping element 4. To increase the stability of the first clamping element 4 the thread connection 11, 12 between the first clamping element 4 and the displacement means 3 is located at the axially outermost end of the first clamping element, as illustrated in Fig. 1.
By means of the above inwardly pressing of the second clamping element 5 the inner surface 15 of the second clamping element 5 is pressed against the outer surface of the inner pipe 6 extending through the second clamping element 5 thereby clamping and securing the inner pipe 6 in a fixed axially position relative to the outer pipe to prevent the inner pipe 6 from axially moving relatively to the outer pipe 1.
On the other hand, if the displacement means 3 is turned in the other rotational direction this causes an axial movement of the second clamping element 5 in the direction away from the first clamping element 4, whereby the conical surfaces 13, 14 of the first and second clamping elements 4, 5 are released from each other. If a certain amount of releasing movement is achieved the end of the second clamping element 5 comprising the conical outer surface 14 returns to its normal position whereby the inner surface 15 of the second clamping element 5 is released from the outer surface of the inner pipe 6 extending through the second clamping element 5. After that, the inner pipe 6 may be axially slided through the second clamping element 5 again to adjust the length of the telescopic suction pipe.
To allow the second clamping element 5 to be resiliently pressed inwardly, the second clamping element 5 is preferably C-shaped in cross section, i.e. the second clamping element 5 comprises a slot extending in its longitudinal direction, as illustrated in Fig. 1.
As shown in Fig. 1, the displacement means 2 further comprises an annular end cover 2. The end cover 2 may be snapped or screwed onto the end of the displacement means 3 opposite to the end provided with the projections 17. The inner diameter of the end cover 2 is approximately the same as the outer diameter of the outer pipe 1 so that the displacement means 3 is supported on the outer surface of the outer pipe 1.
To assembly the above discussed telescopic suction pipe, as a first step the first clamping element 4 is fitted onto the inner pipe 6. Afterwards, a seal ring (not shown) is attached onto the surface of the inner pipe 6 at the end which will extend within the outer pipe 1 in the assembled state. With such a seal ring on the inner pipe 6, the inner pipe 6 may not slide completely out of the outer pipe 1 and the second clamping element 4. Next, the end of the first clamping element 4 being provided with the outer surface portion 19 and the locking projection 8 is inserted into the outer pipe 1 and the locking projection 8 of the first clamping element 4 is engaged with the locking recess 7 of the outer pipe 1.
After that, the assembled outer pipe 1 and first clamping element 4 are pushed into the displacement means 3 from the right side to the left side in Figs. 1 and 2. For this operation, the end cover 2 of the displacement means 3 must not yet be put onto the displacement means 3. From the other side, i.e. from the left side in Figs. 1 and 2, the second clamping element 5 is put onto the inner pipe 5 and pushed into the displacement means 3 for engagement of the inwardly extending projections 17 of the displacement means 3 with the annular grooves 16 of the second clamping element 5. Then, the displacement means 3 is turned to clamp the inner pipe 6 by means of the second clamping element 5 in the above discussed manner. Last, the end cover 2 is snapped onto the displacement means 3.
The testing of the telescopic suction pipe according to the present invention showed that when the inner pipe 6 is clamped by means of the second clamping element 5 the telescopic suction pipe cannot be extended or compressed by hand. Further, contrary to the telescopic suction pipes for vacuum cleaners known from the prior art, the telescopic suction pipe according to the present invention is provided with a stepless length adjustment, i.e. the telescopic suction pipe may be adjusted to any arbitrary length, to satisfy the needs of the user very well.
Furthermore, the adjustment of the length of the telescopic suction pipe according to the present invention is reliably achieved by an easy operation of the displacement means which will result in a more convenient and easier operation of the telescopic suction pipe by the user. The easy construction of the length adjustment arrangement also allows an easy and unexpensive manufacturing and assembling of the telescopic suction pipe according to the present invention.

Claims

A telescopic vacuum cleaner suction pipe comprising: an outer pipe, an inner pipe having an outer diameter smaller than the inner diameter of said outer pipe wherein said inner pipe is axially slidable within the outer pipe and an adjustment means to adjust the length of the suction pipe,
characterised in that
said adjustment means comprises a first clamping element (4) being attached at one end of said outer pipe (1) and having a conical inner surface (13) tapering towards the end opposite to said outer pipe and a second clamping element (5) axially adjacent to said first clamping element (4) and having an inner diameter being slightly greater than the outer diameter (d2) of said inner pipe (6) and a conical outer surface (14) tapering towards its end opposing said first clamping element (4), wherein said second clamping element (5) is axially movable in the direction towards said first clamping element (4) whereby said conical inner surface (13) and said conical outer surface (14) are overlapping each other and an inner surface (15) of said second clamping element (5) is pressed against an outer surface of said inner pipe (6) to clamp said inner pipe (6) in the respective axial position relative to said outer pipe.
The telescopic vacuum cleaner suction pipe as claimed in claim 1,
characterised in that
said clamping means further comprises a displacement means (3) for axially moving said second clamping element (5) in the direction to and away from said first clamping means.
The telescopic vacuum cleaner suction pipe as claimed in claim 2,
characterised in that
said displacement means (3) is provided with an interior thread (11) engaging with an exterior thread (12) provided on said first clamping element (4) so that said displacement means (3) is rotatable around said first clamping element (4) thereby producing an axial movement of said displacement means (3) with respect to said first clamping element (4).
The telescopic vacuum cleaner suction pipe as claimed in claim 2 or 3,
characterised in that
said displacement means (3) comprises a first engagement means (17) for engagement with a second engagement means (16) provided on said second clamping element (5) to connect said displacement means (3) and said second clamping element (5) for a common axial movement.
The telescopic vacuum cleaner suction pipe as claimed in anyone of preceding claims,
characterised in that
said second clamping element (5) is C-shaped in cross section to be resiliently deformable in the radially inward direction.
The telescopic vacuum cleaner suction pipe as claimed in anyone of claims 2 to 5,
characterised by
a limiting means (9, 10) to limit the rotational movement of said displacement means (3) with respect to said first clamping element (4) to prevent separation of the displacement means (3) from said first clamping means (4).
The telescopic vacuum cleaner suction pipe as claimed in anyone of preceding claims,
characterised by
an engagement means (7, 8) for attachment of said outer pipe (1) with said first clamping element (4) in a fixed position.
The telescopic vacuum cleaner suction pipe as claimed in anyone of claims 2 to 7,
characterised by
a supporting means (2) attached at one end of said displacement means (3) for supporting said displacement means (3) on the outer pipe (1).