Patent Publication Number: US-2004050441-A1

Title: Articulated joint for an electric household appliance and electric household appliance comprising said joint

Description:
[0001] This application is based on Italian Patent Application No. MI2002A 001567 filed on Jul. 16, 2002, the content of which is incorporated hereinto by reference.  
       [0002] The present invention relates to an articulated joint for an electric household appliance and an electric household appliance comprising said joint.  
       [0003] More particularly, the present invention relates to a joint for an electric household appliance intended to suck up dust and rubbish.  
       [0004] As is known, an electric household appliance of the said type comprises an accessory for cleaning such as, for example, a suction nozzle or a suction brush.  
       [0005] Said electric household appliance, for example a vacuum cleaner or an electric brush, makes use of a suction tube having a first end associated with said suction accessory and a second end communicating with a container for collecting the dust and rubbish sucked up by said suction accessory.  
       [0006] Usually, a section of said suction tube, if necessary provided with a suitable grip, is manoeuvred by the operator so as to direct the suction accessory on the surface to be cleaned.  
       [0007] In the conventional art, this suction tube section is formed by a long rigid tubing connected, at its far end, to said suction accessory.  
       [0008] Said tube section, which may be provided with a suitable grip and is manoeuvred by the operator so as to direct the suction accessory on the surface to be cleaned, is also called “steering means”.  
       [0009] Conventional steering means have the drawback that said long rigid tubing obliges the operator to bend down whenever the surface to be cleaned is situated underneath a piece of furniture such as, for example, a bed, a table and the like.  
       [0010] Moreover, sometimes, this operation is also hindered by the fact that the space surrounding said furniture is restricted and does not allow said steering means to be introduced easily underneath the furniture.  
       [0011] The present invention aims to overcome the above-mentioned drawbacks.  
       [0012] According to a first aspect thereof, the present invention therefore concerns, by way of steering means, an articulated joint for tubes of electric household appliances, comprising a plurality of axially hollow modular elements, each modular element comprising a male end and a female end, coupling means for joining said modular elements to each other, resilient means fitted to at least two adjacent modular elements, said resilient means being deformable resiliently under the action of a force with simultaneous rotation of a modular element with respect to an adjacent modular element and consequent variation in the configuration from straight to curved and resilient return into the straight configuration when said force ceases to act.  
       [0013] Typically, said axially hollow tubes are made of rigid material.  
       [0014] Preferably, said coupling means retain the male end of a first modular element inside the female end of a second modular element.  
       [0015] Conveniently, said coupling means connect a male end of the first modular element having the form of a substantially spherical head inside the female end of the second modular element.  
       [0016] According to a preferred embodiment, said coupling means comprise a first and a second annular unit, said first annular unit being able to be associated with the male end of the first modular element and said second annular unit being able to be inserted with pressure inside the female end of the second modular element, said first annular unit interfering with said second annular unit so as to retain said two modular elements together.  
       [0017] Typically, said first annular unit comprises two semi-annular bands.  
       [0018] Preferably, said second annular unit comprises a first annular band followed by a portion with a narrower cross-section forming a step and by a second annular band having a smaller diameter than the first band, said second annular unit being able to be inserted with pressure inside said female end of the modular element.  
       [0019] Conveniently, said second annular unit which can be inserted with pressure inside said female end of the modular element is inserted until said second annular band is brought into contact against a suitable shoulder of the modular element.  
       [0020] Preferably, each modular element comprises a substantially spherical head provided with a pair of lateral pins emerging so as to project outwards in opposite directions and each semi-annular band comprises a groove for each receiving one of said pins, each pin having a height not greater than the thickness of said groove.  
       [0021] Advantageously, said groove has a substantially semi-circular shape and houses one of said pins with a small amount of play so as to allow rotation of each element with respect to at least one other element only in a substantially common plane.  
       [0022] However, by providing said grooves with a shape extending longitudinally along a part of the peripheral portion of said semi-annular bands, said pins will be allowed to rotate also with respect to said first annular unit.  
       [0023] Typically, said resilient means are aligned with each other.  
       [0024] Advantageously, said resilient means comprise metal springs, each spring having a first end constrained to a first modular element and a second end constrained to an adjacent modular element. Alternatively, said resilient means consist of a single spring which extends along all the elements of the articulated joint and is constrained to at least two elements of said joint, preferably, to at least the two terminal elements.  
       [0025] As an alternative to the metal springs, the resilient means may be formed by other resiliently deformable bodies made of metal, rubber or other suitable materials.  
       [0026] In another embodiment, said resilient means are associated with the elements of the articulated joint during the process for moulding of the latter.  
       [0027] Conveniently said modular elements comprise means for housing the resilient means,  
       [0028] Advantageously, said housing means comprise in a modular element a single casing formed by two shells having a first closed end and a second open end, each resilient means being inserted in the open end of two shells of two adjacent modular elements.  
       [0029] Conveniently the two terminal elements of said joint are provided at their ends with two hollow cylindrical portions which can be associated with two tubes, a first tube being able to be connected to a suction accessory such as, for example, a nozzle or a brush of said electric household appliance and a second tube being able to be connected to a container for collecting the dust and rubbish sucked up by said accessory of said electric household appliance.  
       [0030] Advantageously, said second tube is provided with a suitable grip.  
       [0031] According to a second aspect thereof, the present invention relates to an electric household appliance comprising an articulated joint according to the present invention. 
     
    
    
     [0032] The present invention will now be further illustrated with the aid of the description which follows and the accompanying figures which are provided solely by way of example and without intended to be limiting, in which:  
     [0033]FIG. 1 shows a front view of an articulated joint according to the invention;  
     [0034]FIG. 2 shows an exploded perspective front view of a modular element according to FIG. 1;  
     [0035]FIG. 3 shows a front perspective view of the element according to FIG. 2, prior to assembly with another element of the joint;  
     [0036]FIG. 4 shows a perspective view of an assembly step following that shown in FIG. 3;  
     [0037]FIG. 5 shows a further perspective view of a step for assembly of the joint, following that shown in FIG. 4;  
     [0038]FIG. 6 shows a constructional detail prior to insertion into an element of the joint. 
    
    
     [0039] The electric household appliance to which reference will be made by way of a non-limiting example is a vacuum cleaner.  
     [0040] This electric household appliance comprises, at a first end “a” of an articulated joint  1  of the invention, a tube  1  which is internally hollow and associated with a suction tube  3  provided with an end suction nozzle  3 ′.  
     [0041] The second end “b” of the articulated joint  1  of the invention is associated with an internally hollow tube  4  which has, connected to it, a hollow connection piece  5  or other connection means with an equivalent hollow shape, communicating with a box-shaped body  5 ′ of the electric household appliance.  
     [0042] This box-shaped body  5 ′ comprises inside it (in a manner known per and therefore not illustrated) both a container (associated with the connection piece  5 ) such as, for example, a bag for collecting dust and rubbish and, optionally, a suction motor.  
     [0043] The box-shaped body  5 ′ also has, integral with it, a grip (not shown) used by the operator in order to manoeuvre said joint  1  and, by means of it, said suction nozzle  3 ′.  
     [0044] The articulated joint  1  comprises a plurality of modular elements  6  which are internally hollow and arranged in succession: said two tubes  2 , 4  are connected to two terminal elements  7 , 8  of the articulated joint  1 .  
     [0045] The articulated joint  1  also comprises coupling means and resilient means associated, as explained further below, with adjacent modular elements.  
     [0046] In the embodiment shown in FIGS.  1 - 6 , said coupling means have only one degree of freedom and are able to allow rotation of a modular element with respect to an adjacent modular element, in a substantially common plane which coincides with the plane of the sheet.  
     [0047] This rotation of each modular element  6  allows the articulated joint  1  to assume different curved configurations depending on the force applied to the “steering means” by the person operating the electric household appliance. By way of example, FIG. 1 shows an angle of inclination α of the articulated joint  1  in a configuration which is curved with respect to the straight configuration.  
     [0048] Advantageously, this angle of inclination α varies between 1° and 90°, and preferably between 20° and 70°.  
     [0049] More particularly, these coupling elements comprise in each modular element  6  (FIG. 2) a male end  9 , having the form of a spherical head  10 , and a female end  11 , intended to receive or retain the male end  9  of an adjacent modular element  6  (FIG. 4).  
     [0050] The coupling means of the end terminal element  7  comprise (FIG. 3) a female end  11  intended to receive and retain by means of interference the male end  9  of the adjacent modular element  6 .  
     [0051] Moreover, the terminal end  7  comprises an end  12  in the form of a cylindrical sleeve  13  which can be associated with the tube  2 .  
     [0052] In turn the coupling means of the terminal element  8  comprise (FIG. 5) a male element  9  which can be inserted in the female end  11  of the adjacent modular element  6 .  
     [0053] Moreover, the terminal element  8  comprises an end  14  in the form of a cylindrical sleeve  15  which can be associated with the tube  4 .  
     [0054] The preferred embodiment of the coupling means envisages the association of the male end  9  and female end  11  with special annular units.  
     [0055] More precisely, said coupling means comprise a first annular unit  16  (FIG. 2) formed by two semi-annular bands  17 , 18  which can be associated with the spherical head  10  of the male end  9 .  
     [0056] Moreover, said coupling means comprise a second annular unit  19  which can be inserted with pressure inside the female end  11  in the direction of the arrow shown in FIG. 6.  
     [0057] Said spherical head  10  also comprises two pins  20  (only one of which is shown in FIG. 2) emerging so as to project laterally outwards and said semi-annular bands  17 , 18  comprise two grooves  21  which are open on the axially external side.  
     [0058] These grooves  21  have a substantially semi-circular shape and receive the pins  20  with a small degree of play. The axes of the two pins  20  are arranged along a straight line m-m (FIG. 2). The height of the pins  20  is not greater than the thickness of the grooves  21 .  
     [0059] With this configuration of the grooves  21 , the coupling means have substantially only one degree of freedom and allow each element ( 6 ) to rotate only in a substantially common plane.  
     [0060] By providing said grooves  21  with a shape extending longitudinally along a part of the peripheral portion of said semi-annular bands  17 , 18 , said pins  20  will be allowed to rotate also with respect to said first annular unit  16 .  
     [0061] During assembly, the semi-annular bands  17 , 18  are associated with the spherical head  10  of the male end  9  and the pins  20  of the head  10  are inserted inside the grooves  21  of these semi-annular bands  17 , 18 .  
     [0062] Locking of the two semi-annular bands  17 , 18  on the head  10  is performed by means of special constraining devices of the interlocking type. For this purpose the band  18  comprises a tooth  22  and a slit  23  which are intended to be constrained, respectively, with a corresponding slit and a corresponding tooth (not shown) of the band  17 .  
     [0063] The coupling means also comprise said second annular unit  19  formed (FIG. 6) by a first annular band  24  followed by a portion with a narrower cross-section forming a step  25  and by a successive second annular band  26  having a diameter smaller than the first band.  
     [0064] During assembly, the second annular unit  19  is inserted with pressure (FIG. 6) inside said female end  11  until the second band  26  comes up against a special shoulder (not shown).  
     [0065] The articulated joint  1  further comprises resilient means formed by aligned metal springs  27 . In FIG. 5 these springs  27  are aligned along the upper portions of the modular elements; each spring  27  has a first end constrained to a modular element  6  or, respectively, to a terminal element  7 , 8  and a second end constrained to an adjacent modular element  6 .  
     [0066] In particular, each spring  27  is housed inside special housing means said housing means being provided in each modular element  6  in the form of a casing  28  (FIG. 2) comprising two shells  29 ,  30 .  
     [0067] The terminal element  7  has only one shell  29 , while the terminal element  8  has only one shell  30 .  
     [0068] These shells  29 ,  30  have a first closed end and a second open end.  
     [0069] The open end  31  of the shell  29  lies substantially in the plane perpendicular to the start of the spherical head  10  and the open end  32  of the shell  30  lies in the same plane as the female end  11 .  
     [0070] Each spring  27  may be housed (FIGS.  3 - 5 ) inside the shell  29  of a first modular element  6  or, at the end b of the joint  1 , of the terminal element  8 , and inside the shell  30  of a second adjacent modular element  6  or, at the end a of the joint  1 , of the terminal element  7 .  
     [0071] During assembly of the articulated joint  1 , it is envisaged assembling together the male end of a modular element  6  or, at the end b of the joint  1 , the male end of the terminal element  8 , and the female end of the adjacent modular element  6  or, at the end a of the joint  1 , the female end of the terminal element  7  (FIG. 4).  
     [0072] This step is performed by inserting with pressure the spherical head  10 —already associated with the semi-annular bands  17 , 18 —of the modular element  6  or, at the end b of the joint  1 , of the terminal element  8 , inside the annular unit  19  already mounted in the adjacent modular element  6  or, at the end a of the joint  1 , in the terminal element  7 .  
     [0073] The male end  9  penetrates inside the first annular band  24  as far as the zone of the pins  20 .  
     [0074] The spherical head  10  is thus able to rotate about the hinge formed by the pins  20  since the height of the pins being less than the thickness of the grooves  21 , does not touch the walls of the first annular band  24 .  
     [0075] Moreover, during insertion of the male end  9  inside the female end  11 , the pairs of shells  29 , 30  of two adjacent elements are brought closer together with consequent initial prestressing of the spring  27  arranged between them.  
     [0076] For this purpose, as illustrated in the figures, the open end  32  of the shell  30  has a greater width than the open end  31  of the shell  29 ; therefore a portion of the shell  29  penetrates inside the shell  30 , achieving the desired prestressing of the spring  27 .  
     [0077] The same steps are repeated in a similar manner for joining together all the modular elements  6  of the joint  1 .  
     [0078] During assembly it is envisaged associating the terminal elements  7 , 8  with the adjacent modular elements  6  by assembling a male end and a female end as already described.  
     [0079] The articulated joint  1  thus constructed is associated with the tubes  2 , 4  by means of the sleeves  13 , 15  of the terminal elements  7 , 8  (FIG. 1).  
     [0080] Advantageously, the operator during operation of the electric household appliance may perform the various cleaning operations while keeping the bust of the body in a substantially erect position.  
     [0081] In fact, the articulated joint  1  is able to assume the most appropriate angles of curvature necessary for introducing the suction nozzle  3 ′ into spaces which are difficult to access such as, for example, underneath a bed or a table, without the operator having to bend down.  
     [0082] Advantageously, during the various operations performed by means of the electric household appliance, the articulated joint  1  retains a controllable structure, despite the presence of a plurality of movable elements  6 , 7 , 8 .  
     [0083] In fact, the resilient deformation imparted to the springs  27  between adjacent elements allows the articulated joint  1  according to the invention to assume and maintain, when a force is applied by the operator, a stable curved configuration in a similar manner to what would occur when a single elastic cord is subjected to a bending moment.  
     [0084] Essentially, the springs  27  prevent a modular element from being subjected to a movement which is not coordinated with respect to that of the other modular elements during operation of the electric household appliance.  
     [0085] Moreover, again advantageously, when force is no longer exerted on the articulated joint  1 , it assumes the initial straight configuration.