Abstract:
A cuff ( 10 ) for joining together an inner and outer pipe ( 16, 14 ), the cuff being slideable along at least part of the inner pipe to allow nesting of the pipes. The cuff ( 10 ) comprises a housing ( 12 ) and an interlocking member ( 28 ). The interlocking member ( 28 ) lies, in use, in a plane extending transversely to the longitudinal axis of the pipes. The interlocking member has an actuator and an interengaging portion for interengaging with the inner pipe ( 16 ). In use, the interengaging portion lies on the side of inner pipe ( 16 ) remote from the actuator portion ( 30 ) so that, when the interlocking member ( 28 ) is translated within the plane on actuation, the interengaging portion is released from the inner pipe. A pair of diametrically opposed lugs (not shown) are located on the interlocking member ( 28 ) and a compression spring (not shown) acts between each lug and the housing ( 12 ) so as to bias the interengaging portion into engagement with the inner pipe.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a cuff for joining together pipes. Particularly, but not exclusively, it relates to a cuff for joining together two pipes in which the cuff is slideable along at least part of one of the pipes to allow nesting of the pipes. 
     It is understood that the term “pipe” referred to throughout the specification includes a rigid pipe or a flexible pipe (hose). 
     BACKGROUND OF THE INVENTION 
     Cuffs of the types referred to above are known for joining the flexible hose portion and the rigid pipe portion of a wand of a vacuum cleaner  1  as shown in FIG.  1 . The cuff  10  is attached to one end of the flexible, extendable hose portion  14  of the wand  3 . The cuff  10  is slideable along the rigid pipe portion  16  so that the rigid pipe portion  16  nests within the flexible hose portion  14  for storage but can be fully extended when in use. In the stored position, the cuff is slid to the uppermost end of the rigid pipe portion  16 , the flexible hose portion  14  rests over the rigid pipe portion  16  and the assembly is then clipped onto the body  5  of the vacuum cleaner with the nozzle  7  of the wand  3  uppermost. The nozzle  7  then forms a handle for manoeuvring the vacuum cleaner over a surface to be cleaned. For above-floor cleaning the wand  3  is unclipped from the body  5  of the vacuum cleaner and the cuff  10  is slid to the lowermost end of the rigid pipe portion  16  so that the wand  3  is fully extended as shown in FIG.  1 . The wand  3  can then be used to clean awkward areas. The flexible pipe portion  14  is extendable giving the user full flexibility. 
     This type of cuff provides a partial seal between the flexible hose portion and the rigid pipe portion so that the air flow path defined by the flexible hose, cuff and rigid pipe portion is continuous but not fully airtight. This can cause loss of suction. The cuff also ensures that the rigid pipe portion and the flexible hose portion are not detached from each other. However, the cuff does not hold the rigid pipe portion with respect to the flexible pipe portion and therefore the cuff can slide along the rigid hose portion during use. This causes the end of the rigid pipe portion to project into the flexible pipe portion which, since the flexible pipe portion will normally follow a curved path, in use, the rigid pipe portion contacts the inner wall of the flexible pipe portion causing wear at the point of contact. At the lowermost end of the rigid pipe portion, there is provided means for preventing it from completely falling out of the cuff. Therefore, for above-floor cleaning tools must be attached to the remote end of the rigid pipe portion. Since the rigid pipe portion is inflexible, it can be awkward for cleaning particularly confined spaces. 
     Another type of known cuff provides means for retaining two or more rigid pipe portions in predetermined positions with respect to each other. Examples are shown and described in WO 94/10494, U.S. Pat. No. 5,090,747 and U.S. Pat. No. 4,863,201. However, such cuffs are generally bulky and are therefore unsuitable for use in situations in which space and weight are at a premium as in the case, for example, of a vacuum cleaner wand of the type shown in FIG. 1, particularly a domestic vacuum cleaner. 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide a cuff for joining together two pipes which can retain the pipes at a predetermined position with respect to each other and which is also compact. The present invention also seeks to provide a cuff for joining together two pipes and which is suitable for use in a wand for a vacuum cleaner, particularly a domestic vacuum cleaner. 
     According to the present invention, there is provided a cuff for joining together an inner pipe and an outer pipe, the cuff being slideable along at least part of the inner pipe to allow nesting of the pipes, the cuff comprising a housing and an interlocking member supported by the housing, the interlocking member lying, in use, around the inner pipe in a plane extending transversely to the longitudinal axis of the inner and outer pipes, and having an actuator portion and an interengaging portion for interengaging with the inner pipe, the interengaging portion lying, in use, on the side of the inner pipe remote from the actuator portion so that, when the interlocking member is translated within the plane on actuation, the interengaging portion is released from the inner pipe, characterised in that a pair of diametrically opposed lugs are located on the interlocking member and in that a compression spring acts between each lug and the housing so as to bias the interengaging portion into engagement with the inner pipe. 
     The interlocking member of the cuff according to the present invention provides means for retaining the cuff at a predetermined position with respect to the inner pipe, thus preventing slippage of the inner pipe when in use and minimising wear. Further, the release of the interengaging portion from the inner pipe by translation of the interlocking member in the plane, which extends transversely to the longitudinal axis of the pipes, provides a more compact cuff which is more suitable for storage where space is minimal. Furthermore the interlocking member generally follows the shape of the pipes to minimise the size of the cuff. The outer edge of the interlocking member and the housing of the cuff are preferably circular or substantially circular so as to conform to the shape of the inner and outer pipes to further minimise the size of the cuff. 
     In providing two compression springs, the bias required to maintain engagement of the tongue and groove is shared. Therefore, the size of the springs can be further reduced and hence also the size of the cuff housing. The cuff enables the inner pipe to be completely released from the cuff so that tools can be inserted directly and held in place by the interlocking member. 
     Preferably, the interengaging portion interengages the inner pipe by a tongue and groove arrangement. In alternative arrangements, the interengaging portion comprises one or two tongues which interengage at least one groove in the inner pipe, or the interengaging portion comprises one or two grooves which interengage a corresponding tongue on the inner pipe. 
     Preferably, the actuator portion comprises a push-button which, when pressed, counteracts the bias of the compression springs to release the interengaging portion from its engagement with the inner pipe. 
     In a preferred embodiment, the interengaging portion comprises a substantially annular ring and the actuator portion is located on the annular ring diametrically opposite the interengaging portion and perpendicular to that joining the lugs. 
     In a preferred embodiment, the cuff further comprises a second interlocking member lying in a plane extending transversely to the longitudinal axis of the inner and outer pipes, and having a second actuator portion and a second interengaging portion for interengaging with the inner pipe, the second interengaging portion lies on the side of the inner pipe remote from the second actuator portion so that, the second interlocking member is translated within the plane on actuation in a direction opposite to the translation of the first interlocking member to release the second interengaging portion from the inner pipe. 
     Preferably, the cuff comprises a seal for sealing the housing and the interlocking member with the inner pipe. Therefore, an improved seal is achieved which provides improved suction when the cuff forms part of a vacuum cleaner. 
     The cuff of the present invention is particularly suitable for joining the inner and outer pipes of a wand for a vacuum cleaner where the inner pipe is a rigid pipe and the outer pipe is a flexible pipe. 
     In the case of use in a wand for a vacuum cleaner therefore, tools can be attached to the flexible hose for above-floor cleaning making the cleaner easier to use in particularly awkward places. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A embodiment of the present invention will now be described with reference to the accompanying drawings, in which: 
     FIG. 1 shows a known vacuum cleaner having a wand which incorporates a cuff; 
     FIG. 2 is a perspective view of a cuff according to the present invention; 
     FIG. 3 is a front view of the cuff of FIG. 2; 
     FIG. 4 is a section taken along the line A—A of the cuff of FIG. 3 in the locked position; 
     FIG. 5 is a section taken along the line B—B of the cuff of FIG. 3 in the locked position; 
     FIG. 6 is a section taken along the line B—B of the cuff of FIG. 3 in the unlocked position; 
     FIG. 7 is a side view of the cuff according to the present invention; 
     FIG. 8 is a section taken along the line C—C of the cuff of FIG. 7; 
     FIG. 9 shows a first alternative arrangement of the interlocking member of the cuff according to the present invention; and 
     FIG. 10 shows a second alternative arrangement of the interlocking member of the cuff according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A cuff according to the present invention is shown in FIGS. 2 to  8  of the drawings. The cuff is described with reference to its use in a wand for a vacuum cleaner. Of course, the cuff may be used in different applications. 
     The cuff  10  has a generally cylindrical housing  12 . One end of a flexible hose  14  is inserted into one end of the housing  12  and fixedly held therein by, for example, gluing or welding. One end of a rigid pipe  16  is slidingly inserted into the other end of the housing  12  so that the cuff joins the flexible hose  14  and rigid pipe  16  together to form a continuous air flow path. The direction of air flow is indicated by the arrow X shown in FIG.  5 . The cuff  10  is slideable along part of the rigid pipe  16  so that the rigid pipe  16  can nest inside the flexible hose  14 . 
     The end of the housing  12  extending over the flexible hose  14  terminates with a bell shaped mouth  18  which helps to reduce wear on the flexible hose  14 . The flexible hose preferably has a stretch ratio of 6.25:1. The mouth  20  at the other end of the housing  12  fitted around the rigid pipe  16  has a reduced inner diameter which corresponds to the outer diameter of the rigid pipe  16 . The mouth  20  is formed from two concentric cylindrical walls, an inner wall  22  and an outer wall  24 . The inner wall  22  and the outer wall  24  are joined by a base or seat  26 , at the end thereof remote from the mouth  20 . 
     An interlocking member  28  is fitted within the housing  12  to rest on the seat  26 . The interlocking member  28  comprises an actuator portion  30  which is a push-button. The actuator portion  30  projects through a hole  32  in the housing  12 . The area surrounding the hole  32  of the housing is flattened to form a generally triangular depression  34 . The interlocking member  28  is held in place by a guide member  36  which is snap fitted into the housing  12  by means of a pair of diametrically opposing projections  38  which engage with corresponding holes  40  in the housing. The guide member  36  abuts against the lower edge of the interlocking member  28  preventing the interlocking member  28  from moving in the direction of the longitudinal axis of the housing  12 . The inner dimension of the guide member  36  corresponds to that of the rigid pipe  16 . 
     The flexible hose  14  is bonded to the outer surfaces of the guide member  36  with adhesive. This provides an excellent seal between the flexible hose  14  and the cuff  10 . This seal is further improved by the fact that the guide member  36  is profiled to match exactly the helical form of the flexible hose  14 . The guide member  36  and the bonded hose  14  are inserted into the bell shaped mouth  18  of the housing  12  of the cuff  10  and snap-fitted into the holes  40  in the housing  12  by holding the interlocking member  28  in the correct position. 
     To form an airtight seal between the components of the cuff  10 , nylon lip seals  44  are provided between the guide member  36  and the housing  12  and between the guide member  36  and the rigid pipe  16 . 
     The rigid pipe  16  has an annular groove  46 . In the drawings, one groove is shown but any number of grooves can be provided at predetermined positions along the length of the rigid pipe  16 . The groove  46  is located towards one end of the rigid pipe remote from the other which is adapted to receive dirty air during use. The interlocking member  28  farther comprises a tongue  48  which extends radially inwards diametrically opposite the push-button  30 . The tongue  48  engages with the annular groove  46  of the rigid pipe  16  in the locked position as shown in FIG. 5 when the rigid pipe is fully extended ready for use and is held in that position, thus preventing any further movement between the rigid pipe  16  and the flexible hose  14 . Wear due to relative movement of this sort is thereby eliminated. 
     The interlocking member  28  extends in the plane perpendicular to the longitudinal axis of the rigid pipe  16 , the flexible hose  14  and the cuff  10  to form an annular zing  49  around the rigid pipe  16 . The inner diameter of the ring  49  is greater than the diameter of the rigid pipe  16  to allow translation in that plane. Alternatively, the interlocking member can have a central aperture which is slightly elliptical or oval, as opposed to circular. The tongue  48  is biased to engage the annular groove  46  of the rigid pipe  16  by means of a pair of diametrically opposite compression springs  50  acting on lugs  53  positioned at either end of a diameter of the interlocking member lying at right angles to that joining of the push-button  30  and the tongue  48 . The compression springs  50  rest above the guide member  36  in recesses  51  formed in the wall of the housing  12  and act against the ends of those recesses. 
     To release the tongue  48  from the groove  46 , the push-button  30  is pressed radially inwardly against the bias of the compression springs  50  so that the interlocking member  28  translates in the plane perpendicular to the longitudinal axis of the flexible hose  14  and rigid pipe  16  by a distance of approximately 1.75 mm until the tongue  48  is clear of the groove  46 . The rigid pipe  16  can then slide with respect to the cuff  10  as shown in FIG.  6 . The interlocking member  28  remains in this unlocked position until the tongue  48  engages a groove in the rigid pipe  16 . 
     FIG. 9 shows an alternative arrangement of the interlocking member of the present invention. The other common components of the cuff as shown in FIGS. 2 to  8  have been omitted here for simplicity. The interlocking member  128  comprises a push-button  130  and an arcuate member  149 . The arcuate member  149  extends partly around the inner, rigid pipe  116  in a plane extending transversely to the longitudinal axis of the pipe. The push-button  130  is located at the midpoint of the arcuate member  149  so as to protrude from the housing as in the embodiment described above. A tongue  148  is located at each end of the arcuate member  149 . The tongues  148  extend inwardly to interengage with the rigid pipe  116  on the side of the pipe remote from the push-button  130 . As in the embodiment described above, the tongues  148  engage with at least one annular groove (not shown) in the inner pipe  116 . A pair of compression springs  150  are provided to act on the arcuate member  149  to bias the tongues  149  into the groove. The springs  150  are located diametrically opposite each other on either side of the push-button  130  as before. 
     FIG. 10 shows another alternative arrangement of the interlocking member of the present invention. The other common components of the cuff as shown in FIGS. 2 to  8  have been omitted here for simplicity. 
     The interlocking member  328   a ,  328   b  comprises a pair of members, a first interlocking member  328   a  and a second interlocking member  328   b . Each member is similar to the interlocking member  28  described with reference to FIGS. 2 to  8 . This arrangement could also be realised with the interlocking member described with reference to FIG.  9 . 
     The first interlocking member  328   a  rests on a seat  326  formed by an inner wall  322  and an outer wall  324  of the housing  312  of the cuff  310  as described above with reference to FIGS. 2 to  8 . The second interlocking member  328   b  rests against the first interlocking member  328   a  and a guide member  336 . The guide member  336  corresponds to that described above with reference to FIGS. 2 to  8 . A flexible hose (not shown) is attached to the housing as described above with reference to FIGS. 2 to  8 . 
     Each interlocking member  328   a ,  328   b  comprises a push-button  330   a ,  330   b . Each push-button  330   a ,  330   b  projects through a hole  332   a  and  332   b  in the housing  312 . Each hole  332   a  and  332   b  are located diametrically opposite each other and displaced in the direction of the longitudinal axis of the housing  312  so that the push-buttons  330   a ,  330   b  of the first and second interlocking member  328   a ,  328   b  are diametrically opposite and project through their respective holes  332   a ,  332   b.    
     Each interlocking member  328   a ,  328   b  also comprises a tongue  348   a ,  348   b  which extends radially inwards diametrically opposite its respective push-button  330   a ,  330   b . Each tongue  348   a ,  348   b  engages an annular groove  346  formed in a rigid pipe  316 . In the drawing, one groove is shown but any number of grooves can be provided at predetermined positions along the length of the rigid pipe  316 . The groove  346  is located towards one end of the rigid pipe remote from the other which is adapted to receive dirty air during use. 
     Each tongue  348   a ,  348   b  is formed on the inner side of the first and second interlocking member  328   a ,  328   b  which rest against each other so that each tongue  348   a ,  348   b  simultaneously engages the same groove  346 . 
     To release the tongue and groove arrangement both push-buttons  330   a ,  330   b  of the first and second interlocking members  328   a ,  328   b  are pushed radially inwards, as indicated by the arrows Y and Z, at the same time, to counteract the bias of the compression springs (not shown). In this way the two interlocking members  328   a ,  328   b  share the compression springs. Pressing the push-buttons  330   a ,  330   b  causes each interlocking member  328   a ,  328   b  to move in the plane perpendicular to the longitudinal axis of the housing  312  of the cuff  310  in opposing directions until each tongue  348   a ,  348   b  is clear of the groove  346 . The rigid pipe  316  can then slide with respect to the cuff  310 . 
     The tongue and groove arrangement described, with reference to FIGS. 2 to  10  can be interchanged so that the tongue is either part of the interlocking member  28 , 128 , 328   a , 328   b  or is located on the inner pipe  16 , 116 , 316  and the groove is either located on the inner pipe  16 , 116 , 316  or on the interlocking member  28 , 128 , 328   a , 328   b.    
     In the preferred embodiments described above, the cuff joins a flexible hose to a rigid pipe. The cuff slides along the rigid pipe so that the rigid pipe and flexible hose are nested which is particularly useful for use in a wand of a vacuum cleaner as shown in FIG.  1 . Further, the rigid pipe can be removed from the cuff and tools can be attached to the flexible hose via the cuff. The vacuum cleaner  1  is preferably of the type containing a cyclonic separator. 
     In the light of this disclosure, modifications of the described embodiments as well as other embodiments, all within the scope of the appended claims, will now become apparent to persons skilled in the art.