Abstract:
This invention relates to a telescopic vacuum cleaner tube comprising a first inner tube, a second inner tube, and an outer tube, wherein the first and second inner tubes are arranged to form first and second telescopic links relative to first and second end portions of the outer tube, respectively. The outer tube forms the intermediate tube of the three-part tube while at the same time being fully accessible in any position, whereby one common grip for operating both of the two respective telescopic links, formed by the first and second inner tubes and the intermediate outer tube, of the three part telescopic tube is obtained.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to a telescopic tube for a vacuum cleaner, and more particularly to a three part telescopic tube. 
       BACKGROUND OF THE INVENTION 
       [0002]    The idea of using telescopic tubes to be able to adjust the length of a vacuum cleaner tube is known. One advantage with telescopic vacuum cleaner tubes is to be able to optimize the tube length for a specific cleaning task or for the height of a person that is using the vacuum cleaner. Telescopic tubes also provide the benefit of minimizing the length of the tube when not in use, thus facilitated storage is provided. 
         [0003]    The basic concept of telescopic tubes is to have an inner tube that is movably arranged within an outer tube. The tubes are further provided with a locking member, for instance a simple form of recess and engagement means that is released by means of a control mechanism, for instance by pressing down a release button, while the user pushes or pulls out the movable tube with respect to the outer tube. When the required length of the tube has been reached the locking member keeps the inner tube in position. 
         [0004]    Telescopic tubes comprising three tubes joined with two telescopic links in the same unit are available on the market today. With two telescopic links a telescopic tube, which can be minimized in respect to its maximum length, i.e. when the two movable tubes are fully extended, is obtained. The two telescopic links are controlled by two separate control mechanisms, each controlling one individual telescopic link. A problem with this known three-part telescopic tube is that the adjusting the length of the tube by operating the telescopic links can be experienced as troublesome. 
       SUMMARY OF THE INVENTION 
       [0005]    It is one object of the present invention to provide a three part telescopic tube for a vacuum cleaner that alleviates the above-mentioned problem of the prior art. This object may be achieved by a telescopic tube for a vacuum cleaner according to the present invention as defined in claim  1 . 
         [0006]    Thus, in accordance with an aspect of the present invention, there is provided a telescopic tube for a vacuum cleaner, comprising a first inner tube, a second inner tube, and an outer tube. The first and second inner tubes are slidably arranged inside the outer tube and the first and second inner tubes are lockable relative the outer tube. The first inner tube is arranged relative to a first end portion of the outer tube to form a first telescopic link with the outer tube such that the first inner tube is extendable from the first end portion. The second inner tube is arranged relative to a second end portion of the outer tube to form a second telescopic link with the outer tube such that the second inner tube is extendable from the second end portion. 
         [0007]    Thus, there is provided a three-part telescopic tube for a vacuum cleaner, where the outer tube encompasses two inner tubes that each are arranged to form a telescopic link at a respective end of the outer tube. Hence, the outer tube forms the intermediate tube of the three-part tube while it at the same time is fully accessible in any position: the fully extended position, the fully retracted position or any intermediate position between these positions. Thus both tubes are easily accessible at their respective ends at all times, and the total length of the tube is easily adjustable. 
         [0008]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  2 , the first inner tube and the first end portion of the outer tube are arranged with a first releasable locking member, and the second inner tube and the second end portion of the outer tube are arranged with a second releasable locking member. Due to the releasable locking members, the tubes can be securably locked relative each other in a locking position of the locking members and easily movable relative each other in a released position of the locking members. 
         [0009]    In accordance with the telescopic tube for a vacuum cleaner, as defined in claim  3 , the telescopic functions of the two respective telescopic links can be easily controlled by a control mechanism for the locking members, which control mechanism is arranged on the outside of the outer tube. 
         [0010]    In accordance with the telescopic tube for a vacuum cleaner as defined in claim  4 , the control mechanism is arranged to control the first and second locking members simultaneously. 
         [0011]    This exemplary embodiment of the invention provides a telescopic three-part tube, that has two telescopic links that are controlled with only one control mechanism that is arranged to control the first and second locking members simultaneously. The telescopic tube is thereby allowed to be operated from retracted to extended positions by a one grip operation, which may simplify the length adjustment of the telescopic tube. Using one control mechanism also may simplify the construction complexity compared with prior three-part tubes, i.e. fewer parts can be used, and thus the manufacturing costs of the tube can be decreased. 
         [0012]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner the control mechanism comprises an interconnecting part between the first locking member and the second locking member, which is favourable for allowing simultaneous control of the first and second locking member. 
         [0013]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  5 , the interconnecting part is at least a part of a cylinder shell surface encompassing the outer tube. Since the outer tube is accessible in all position it allows for a common grip when extending and/or retracting the first and second telescopic links. The interconnecting part may be an integrated part of the outer tube. 
         [0014]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  6 , the first locking member and the second locking member are arranged to be released when receiving a longitudinally directed force in excess of a predefined threshold force. Hence, the operation of the telescopic tube is user friendly. The user only has to hold the outer tube with one hand and push or pull the inner tubes with the other hand to change the inner tube positions. According to an example embodiment, it is even possible to extend or retract the first and second inner tubes at the same time by using a third support, e.g. one foot on the suction nozzle, to hold one end of the telescopic tube and then push or pull the tubes in the required direction. 
         [0015]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  7 , the control mechanism includes a releasable locking device for releasing the first and second locking members allowing the repositioning of the inner tubes to a required position. When deactivating the locking device and after reaching the new required position, the locking device then locks the telescopic tube in the new position. 
         [0016]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  8 , the outer tube has a larger diameter than the first inner tube and the second inner tube, and the second inner tube has a larger diameter than the first inner tube. Thus, the first inner tube can be retracted into the second inner tube, which in turn can be retracted into the outer tube. This allows for achieving a reduced length of the telescopic tube in the fully retracted position. Thus, valuable space can be saved when storing the tube. 
         [0017]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  9 , the position of the inner tubes relative to the outer tube is continuously adjustable, thus making it possible for the user to make a precise adjustment of the length to fit to his or her own height or to some other required criteria, like for instance required radial range of the vacuum cleaner tube. 
         [0018]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  10 , the position of the inner tubes relative to the outer tube is stepwise adjustable, allowing fixed preferred positions of the telescopic tube. 
         [0019]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  11 , at least one of the first and second inner tubes is connectable to a vacuum cleaner nozzle. According to an exemplary embodiment, wherein the first inner tube has a smaller diameter than the second inner tube, it may be more favorable to connect the vacuum cleaner nozzle to the first inner tube than the second inner tube. Due to the first inner tube having a smaller diameter than the second inner tube, the air steam will flow from a smaller diameter tube to a greater diameter tube, reducing the risk that dust particles in the air stream will clog the tube or that larger debris will get stuck further up the tube. Furthermore, placing the first inner tube with the smallest diameter closest to the vacuum cleaner nozzle may be favorable to the weight distribution of the vacuum cleaner tube, and may make the telescopic tube easier to manoeuvre. 
         [0020]    In accordance with an embodiment of the telescopic tube for a vacuum cleaner as defined in claim  12 , at least one of the first and second inner tubes is connectable to a vacuum cleaner housing or a flexible tube. The telescopic tube is advantageously connected directly to the vacuum cleaner housing or to a flexible tube, depending on the type of vacuum cleaner. On an upright model one end of the telescopic tube is preferably placed directly on the vacuum cleaner housing while the other end is provided with a handle, while on a canister model the telescopic tube is used as the vacuuming tube and is connected to a vacuum cleaner nozzle at one end and to a flexible tube at the other end. In an alternative upright model the telescopic tube is used as a vacuuming tube and is connected to a vacuum cleaner nozzle at one end, and to the vacuum cleaner housing at the other end, as shown in  FIG. 5 . 
         [0021]    These and other aspects, features, and advantages of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter, but are not intended to limit the scope of the claimed or disclosed invention in any way. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    The invention will now be described in more detail and with reference to the appended drawings in which: 
           [0023]      FIG. 1  shows schematic drawings of an embodiment of a telescopic tube for a vacuum cleaner according to the present invention:  a ) in fully extended position,  b ) in an intermediate position,  c ) in an intermediate position, and  d ) in fully retracted position; 
           [0024]      FIG. 2   a ) and  b ) shows cross-sectional views of an embodiment of a telescopic tube for a vacuum cleaner according to the present invention; 
           [0025]      FIG. 3   a ) and  b ) shows cross-sectional views of an embodiment of a telescopic tube for a vacuum cleaner according to the present invention. 
           [0026]      FIG. 4  shows a cross-sectional view of an embodiment of a telescopic tube for a vacuum cleaner according to the present invention. 
           [0027]      FIG. 5   a ) and  b ) shows schematic drawings of embodiments of a telescopic tube for a vacuum cleaner according to the present invention. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0028]    Referring to  FIG. 1   a ), there is shown a schematic drawing of a telescopic tube for a vacuum cleaner  10  according an embodiment of the present invention. The telescopic tube  10  comprises a first inner tube  11 , herein after referred to as the lower tube  11 , a second inner tube  12 , herein after referred to as the upper tube  12 , and an outer tube  13 . The upper tube  12  is arranged to be longitudinally movable inside the outer tube  13 , while the lower tube  11  is arranged to be longitudinally movable inside the upper tube  12  and the outer tube  13 . Hence, the outer tube  13  can encompass at least a portion of the upper tube  12  and at least a portion of the lower tube  11 . In this embodiment the outer tube  13  is of about the same length as, but somewhat shorter than, the lower tube  11  and upper tube  12 . Hence, the outer tube  13  contributes to a substantial part of the fully extended telescopic tube  10 , while at the same time allowing the inner tubes,  11  and  12 , to be almost fully retracted into the outer tube  13 . This minimizes the length of the fully retracted position of the telescopic tube  10  with respect to the fully extended position of the telescopic tube  10 . However, in an alternative embodiment the length proportions of the lower tube  11 , the upper tube  12  and the outer tube  13  may be chosen differently and such alternatives are not excluded from the scope of the invention as claimed. 
         [0029]    The telescopic tube  10  further comprises a control mechanism  14 , which is arranged at the outer tube  13 , and further controls the longitudinal movability of the upper tube  12  and the lower tube  11 . 
         [0030]      FIG. 1   a ) shows the telescopic tube  10  in its fully extended position, with the upper tube  12  and the lower tube  11  in the maximum extended position out of the outer tube  13 , with only a minor part of the total length of the upper tube  12  and the lower tube  11  still arranged inside the outer tube  13 . To manipulate the telescopic tube  10  into a fully retracted position, the user simply holds the outer tube  13 , and hence the control mechanism  14 , with a first hand and then apply a longitudinal force onto, for instance, the upper tube  12  with a second hand, i.e. the user holds the tube  12  and pushes it towards the outer tube  13 , see  FIG. 1   b ). The user then holds the lower tube  11  with his second hand, while keeping the first hand on the outer tube  13 , and pushes the lower tube  11  towards the outer tube  13 , see  FIG. 1   c ). To manipulate the telescopic tube  10  from fully retracted position, which is shown in  FIG. 1   d ) to fully extended position, the user simply holds the outer tube  13 , and the control mechanism  14 , with a first hand and then apply a longitudinal force on to, for instance, the upper tube  12  with a second hand, i.e. holds the tube  12  and pulls it out of the outer tube  13 . Then the user holds the lower tube  11  with his second hand, while keeping the first hand on the outer tube  13 , and pulls the lower tube  11  out of the outer tube  13 . Any intermediate position between the fully extended position and fully retracted position is allowed for the lower tube  11  and the upper tube  12 . 
         [0031]    In this embodiment the control mechanism is activated by overcoming a threshold force working on each locking member, such as described herein under. 
         [0032]    Referring now to  FIG. 2 , which shows a cross-sectional view of an embodiment of the invention, the relation between the diameters of the three tubes  11 ,  12 , and  13 , is set so that the outer tube  13  has a diameter that is larger than the diameter of the upper tube  12 , while the upper tube  12  has a larger diameter than the lower tube  11 . Hence, the outer tube  13  encompasses both inner tubes,  11  and  12 , when the telescopic tube  10  is in a retracted position. A vacuum cleaner nozzle  40  preferably, as shown in  FIG. 2   b ), is connected to the lower tube  11 . In an alternative embodiment of the present invention the inner tubes,  11  and  12 , have the same diameter. 
         [0033]    The control mechanism  14 , which preferably is arranged at the outer tube  13 , comprises a first locking member  15  and a second locking member  16 . The first releasable locking member  15  is arranged at a first end portion  13   a  of the outer tube  13  and bears against the lower tube  11 . The first locking member  15  is arranged to lock the position of the lower tube  11 . The second locking member  16  is arranged at a second end portion  13   b  of the outer tube  13  and bears against the upper tube  12 . The second locking member  16  is arranged to lock the position of the upper tube  12 . When the control mechanism  14  is subjected to a longitudinally applied force, according to the description above where retraction and protraction of the telescopic tube was done by simply pulling or pushing the constituent tubes  11 ,  12 , and  13  apart or together, respectively, the control mechanism  14  is arranged to release the first locking member  15  and the second locking member  16  simultaneously. The longitudinally directed force must exceed a predefined threshold force, i.e. the received force must be greater than the force imparted onto the inner tubes,  11  and  12 , by the locking members holding the upper tube  12  and lower tube  11  in position. When the locking members,  15  and  16 , are released the inner tubes,  11  and  12 , are longitudinally movable relative to the outer tube  13 . When the control mechanism  14  is no longer subjected to a longitudinal force, the locking members are reactivated and lock the inner tubes  11  and  12  in position. 
         [0034]    According other embodiments of a telescopic tube for a vacuum cleaner, the locking members,  15  and  16 , are provided as friction devices or clamping devices (such as conical wedges or the like) or a combination thereof. In these embodiments the positions of the inner tubes  11 ,  12  relative to the outer tube  13  are continuously adjustable. When using friction as the locking mechanisms  15  and  16 , the control mechanism  14  is preferably designed as an integrated part of the outer tube  13  or the control mechanism  14  is designed to simply constitute the outer tube  13 . An alternative way to manipulate the telescopic tube  10  from the fully retracted position, which is shown in  FIG. 1   d ) to the fully extended position, is in this alternative embodiment that the user holds the lower tube  11  with a first hand and then applies a force on to the upper tube  12  with a second hand, i.e. holds the tube  12  and pulls the lower tube  11  and upper tube  12  apart. 
         [0035]      FIGS. 3 and 4 , show cross-sectional views of embodiments according to the present invention. Hereinafter the telescopic link for the upper tube  12  is described, but the description is valid for the telescopic link for the lower tube  11  as well. Here, the upper tube  12  (and lower tube  11 ) is provided with a guide track  20  extending along the upper tube  12 , and a plurality of positioning recesses  21  distributed along the upper tube  12 . The guide track  20  is arranged to engage with a guide protrusion  30  arranged on the locking member  16 . The function of the guide protrusion  30  and the guide track  20  is to keep the upper tube  12  from turning with respect to the outer tube  13  and can be arranged anywhere around the circumference of the upper tube  13 . The locking member  16  further comprises a positioning protrusion  31  that is arranged to lock the longitudinal position of the upper tube  12  by engaging with any one of the positioning recesses  21 . The locking member  16  is further provided with an M-shaped portion  37 , se  FIG. 4 , which is kept in position with two biasing springs  32  and  33 . A protruding portion  34  on the M-shaped portion  37  is arranged to press against the positioning protrusion  31  which then remains engaged with a positioning recess  21 . When the control mechanism  14  is operated, according to the description above, a longitudinally applied force in excess of a threshold force works on the control mechanism  14 , whereby one of the biasing springs  32  or  33  is compressed and the protruding portion  34  of the M-shaped portion  37  is repositioned to release the locking member  16  (and locking member  15 ) when the positioning protrusion  31  is released. When the locking member  16  is released the upper tube  12  is movable longitudinally relative to the outer tube  13 . When the control mechanism is no longer subjected to a force, the protruding portion  34  of the M-shaped portion  37  is repositioned to lock the locking member  16  when the positioning protrusion  31  engages with another positioning recess  21   b , whereby the position of the upper tube  12  is fixed. In this embodiment the position of the inner tubes,  11  and  12 , relative to the outer tube  13  is stepwise adjustable due to the stepwise distribution of the positioning recesses  21 . 
         [0036]    It should be clear that the locking members can be realized in a number of ways by any suitable well-known telescopic tube locking means. 
         [0037]    In an alternative embodiment, the upper, lower and outer tubes,  11 ,  12 , and  13 , have an oval shape, hence guide tracks are not necessary, because the shape of the tubes prevents the tubes from rotating with respect to each other. Hence, the guide protrusion  30  and guide track  20  can be left out of the construction. Of course, any other suitable cross section can be used for the tubes, for example a rectangular or a polygonal cross section. 
         [0038]    In an alternative embodiment of the telescopic tube for a vacuum cleaner at least one of the inner tubes  11 ,  12  is arranged to be fully detachable from the outer tube  13 . 
         [0039]    In an alternative embodiment of the telescopic tube for a vacuum cleaner the control mechanism further includes a releasable locking device  18 , for locking the inner tube  11  and the upper tube  12  in position. 
         [0040]    Referring now to  FIG. 5 , a telescopic tube  10  according to an embodiment of the present invention is connectable to a vacuum cleaner housing. As it can be seen in  FIG. 5   a ) the telescopic tube  10  is connected to the top of a vacuum cleaner housing  55  of an upright vacuum cleaner  50 . The upper tube  12  (or lower tube  11  if the telescopic tube  10  is connected to the upright vacuum cleaner via the upper tube  12 ) is here preferably provided with a handle  56 , which may be fixed or detachable. 
         [0041]    In  FIG. 5   b ) the upper tube  12  of a telescopic tube  10 , according to an embodiment of the present invention, is connected to a flexible vacuum cleaner tube  70 , which flexible vacuum cleaner tube  70  is connected to a canister vacuum cleaner  60 , an upright vacuum cleaner, or a remote central vacuum. The lower tube  11  of the telescopic tube  10  is connected to a vacuum cleaner nozzle  40 . In an alternative embodiment the telescopic tube  10  is connected to a vacuum cleaner housing  55  in one end and a vacuum cleaner nozzle  40  in the other end as illustrated for the vacuum cleaner model shown in  FIG. 5   c ). 
         [0042]    Embodiments of a telescopic tube for a vacuum cleaner according to the present invention have been described herein. These should be seen as merely non-limiting examples. As understood by a skilled person, many modifications and alternative embodiments are possible within the scope of the invention. 
         [0043]    It is to be noted, that for the purposes of this application, and in particular with regard to the appended claims, the word “comprising” does not exclude other elements or steps, and that the words “a” and “an”, do not exclude a plurality, which will be apparent to a person skilled in the art.