Abstract:
A hand held appliance including a wall, a fluid flow path extending within the wall from a fluid inlet into the appliance to a fluid outlet from the appliance, a fan unit extending longitudinally within the wall for drawing fluid into the fluid inlet wherein the fan unit is non-concentric with respect to the wall. The fan unit may be positioned coaxially within the fluid flow path. The wall has a thickness and the thickness of the wall may varies. The wall may be generally tubular and the thickness of the wall varies around a circumference of the wall. The wall may be generally tubular and has an inner surface and an outer surface. A central axis of the inner surface may be different to a central axis of the outer surface.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priority of United Kingdom Application No. 1422356.4, filed Dec. 16, 2014, the entire contents of which are incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    This invention relates to a hand held appliance and in particular a hair care appliance such as a hairdryer. 
       BACKGROUND OF THE INVENTION 
       [0003]    Generally, a motor and fan are provided which draw fluid into a body; the fluid may be heated prior to exiting the body. The motor is susceptible to damage from foreign objects such as dirt or hair so conventionally a filter is provided at the fluid inlet. The fan and heater require power in order to function and this is provided via internal wiring from either a mains power cable or batteries attached to the appliance. 
       SUMMARY OF THE INVENTION 
       [0004]    According to a first aspect, the invention provides a hand held appliance comprising a wall, a fluid flow path extending within the wall from a fluid inlet into the appliance to a fluid outlet from the appliance, a fan unit extending longitudinally within the wall for drawing fluid into the fluid inlet wherein the fan unit is non-concentric with respect to the wall. 
         [0005]    According to an aspect, the invention provides a hand held appliance comprising a wall, a fluid flow path extending within the wall from a fluid inlet into the appliance to a fluid outlet from the appliance, a fan unit for drawing fluid into the fluid inlet wherein the fan unit is positioned asymmetrically within the wall.  
         [0006]    According to another aspect, the invention provides a hand held appliance comprising a wall, a fluid flow path extending within the wall from a fluid inlet into the appliance to a fluid outlet from the appliance, a fan unit for drawing fluid into the fluid inlet wherein the fan unit is eccentric with respect to the wall. 
         [0007]    The fan unit comprises an impeller and a motor for driving the impeller. Preferably, the impeller is axially aligned within the wall. 
         [0008]    Preferably, the fan unit is positioned coaxially within the fluid flow path. Thus, the fluid flow path is non-concentric, asymmetrical or eccentric within the wall. 
         [0009]    The fan unit is located within the fluid flow path between the fluid inlet and the fluid outlet. Thus, the impeller and the motor for driving the impeller are located within the fluid flow path between the fluid inlet and the fluid outlet. Fluid that enters the fluid inlet flows passed the impeller and the motor for driving the impeller. 
         [0010]    Having the fan unit and fluid flow path positioned off centre within the wall has a number of advantages; it provides a space within the wall for housing components, for example the wires; this space is provided with a smaller increase in diameter than if all the components were axially aligned. 
         [0011]    Preferably, the wall has a thickness and the thickness of the wall varies. It is preferred that the wall is generally tubular and the thickness of the wall varies around a circumference of the wall. Preferably, the wall is generally tubular and has an inner surface and an outer surface. It is preferred that a central axis of the inner surface is different to a central axis of the outer surface. 
         [0012]    It is preferred that the wall is formed from two parts. Preferably one of the wall parts is thicker than the other one of the wall parts.  
         [0013]    Preferably, power is supplied to the fan unit by wires extending from a power source and wherein the wires extending from the power source are housed in the wall. It is preferred that the wall is locally thicker in the vicinity of the wires. 
         [0014]    Preferably, wherein the wall comprises channels extending along the wall for housing the wires. It is preferred that the channels extend along the wall at least passed the fan unit. 
         [0015]    Preferably, the appliance comprises a control switch, wherein the control switch is aligned with the wires. 
         [0016]    Preferably, the appliance comprises a control switch wherein the control switch is aligned with the channels. 
         [0017]    In a preferred embodiment, the appliance has a body comprising a first end and a second end and a handle extending from the body wherein the wires extend along the handle in the wall and the wires are radially located within the handle proximate the first end of the body. 
         [0018]    Preferably, the appliance comprises a control switch, wherein the control switch is proximate the first end of the body. 
         [0019]    Preferably, the second end of the body comprises the fluid outlet from the appliance. 
         [0020]    It is preferred that the handle comprises the fluid inlet into the appliance. 
         [0021]    Preferably, the body comprises a further fluid inlet into the appliance. 
         [0022]    Preferably, a further fluid flow path extends axially through the appliance from the further fluid inlet to the second end of the body.  
         [0023]    It is preferred that the handle is orthogonal to the body and the fluid inlet is disposed at the distal end of the handle from the body. 
         [0024]    Preferably, the fan unit comprises an impeller and a motor for driving the impeller. 
         [0025]    It is preferred that the impeller is aligned axially within the wall. 
         [0026]    Preferably, the appliance is a hair care appliance. 
         [0027]    Preferably, the hair care appliance is a hairdryer. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0028]    The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
           [0029]      FIG. 1  shows a hairdryer according to the invention; 
           [0030]      FIG. 2  shows a cross-section through line A-A of the hairdryer shown in  FIG. 1 ; 
           [0031]      FIG. 3 a    shows a further cross-section though the hairdryer shown in  FIG. 1 ; 
           [0032]      FIG. 3 b    shows an enlarged view of the inlet area of the hairdryer shown in  FIG. 3 a   ; 
           [0033]      FIG. 4  shows a an isometric view of the inner structure of the handle of the hairdryer of  FIG. 1 ;  
           [0034]      FIG. 5  shows a cross section through the hairdryer of  FIG. 1  at line B-B; 
           [0035]      FIG. 6  shows a cross section through the hairdryer of  FIG. 1  at line C-C; and 
           [0036]      FIG. 7  shows a cross section through the hairdryer of  FIG. 1  at line D-D; 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0037]      FIGS. 1, 2, 3   a  and  3   b  show a hairdryer  10  with a handle  20  and a body  30 . The handle has a first end  22  which is connected to the body  30  and a second end  24  distal from the body  30  and which includes a primary inlet  40 . Power is supplied to the hairdryer  10  via a cable  50 . 
         [0038]    Referring now to  FIGS. 2 and 3   a  in particular which show a simplified version of the internal components of the hairdryer, the handle  20  has an outer wall  200  which extends from the body  30  to a distal end  24  of the handle. At the distal end  24  of the handle an end wall  210  extends across the outer wall  200 . The cable  50  enters the hairdryer through this end wall  210 . The primary inlet  40  in the handle  20  includes first apertures that extend around and along  42  the outer wall  200  of the handle and second apertures that extend across  46  and through the end wall  210  of the handle  20 . The cable  50  is located approximately in the middle of the end wall  210  so extends from the centre of the handle  20 . 
         [0039]    It is preferred that the cable  50  extends centrally from the handle  20  as this means the hairdryer is balanced regardless of the orientation of the handle  20  in a users&#39; hand. Also, if the user moves the position of their hand on the handle  20  there will be no tugging from the cable  50  as it does not change position with respect to the hand when the hand is moved. If the cable were offset and nearer one side of the handle then the weight distribution of the hairdryer would change with orientation which is distracting for the user.  
         [0040]    Upstream of the primary inlet  40 , a fan unit  70  is provided. The fan unit  70  includes a fan and a motor. The fan unit  70  draws fluid through the primary inlet  40  towards the body  30  through a fluid flow path  400  that extends from the primary inlet  40  and into the body  30  where the handle  20  and the body  30  are joined  90 . The fluid flow path  400  continues through the body  30 , around a heater  80  and to a primary fluid outlet  440  where fluid that is drawn in by the fan unit exits the primary fluid flow path  400 . The primary fluid flow path  400  is non linear and flows through the handle  20  in a first direction and through the body  30  in a second direction which is orthogonal to the first direction. 
         [0041]    The body  30  has a first end  32  and a second end  34  and includes an outer wall  360  and an inner duct  310 . The primary fluid flow path  400  extends along the body from the junction  90  of the handle  20  and the body  30  between the outer wall  360  and the inner duct  310  towards the primary fluid outlet  440  at the second end of the body  30 . 
         [0042]    Another fluid flow path is provided within the body; this flow is not directly processed by the fan unit or the heater but is drawn into the hairdryer by the action of the fan unit producing the primary flow through the hairdryer. This fluid flow is entrained into the hairdryer by the fluid flowing through the primary fluid flow path  400 . 
         [0043]    The first end  32  of the body includes a fluid inlet  320  and the second end  34  of the body includes a fluid outlet  340 . Both the fluid inlet  320  and the fluid outlet  340  are at least partially defined by the inner duct  310  which is an inner wall of the body  30  and extends within and along the body. A fluid flow path  300  extends within the inner duct from the fluid inlet  320  to the fluid outlet  340 . At the first end  32  of the body  30 , a side wall  350  extends between the outer wall  360  and the inner duct  310 . This side wall  350  at least partially defines the fluid inlet  320 . At the second end  34  of the body a gap  370  is provided between the outer wall  360  and the inner duct  310 , this gap  370  defines the primary fluid outlet  440 . The primary fluid outlet  440  is annular and surrounds the fluid flow path. The primary fluid outlet  440  may be internal so the primary fluid flow path   400  merges with the fluid flow path  300  within the body  30 . Alternatively, the primary fluid outlet  440  is external and exits from the body  30  separately to the fluid from the fluid flow path  300  at the fluid outlet  340 . 
         [0044]    A printed circuit board (PCB)  75  including the control electronics for the hairdryer is located in the body  30  near the side wall  350  and fluid inlet  320 . The PCB  75  is ring shaped and extends round the inner duct  310  between the inner duct  310  and the outer wall  360 . The PCB  75  is in fluid communication with the primary fluid flow path  400 . The PCB  75  extends about the fluid flow path  300  and is isolated from the fluid flow path  300  by the inner duct  310 . 
         [0045]    The PCB  75  controls such parameters as the temperature of the heater  80  and the speed of rotation of the fan unit  70 . Internal wiring (not shown) electrically connects the PCB  75  to the heater  80  and the fan unit  70  and the cable  50 . Control buttons  62 ,  64  are provided and connected to the PCB  75  to enable a user to select from a range of temperature settings and flow rates for example. 
         [0046]    In use, fluid is drawn into the primary fluid flow path  400  by the action of the fan unit  70 , is optionally heated by the heater  80  and exits from the primary fluid outlet  440 . This processed flow causes fluid to be entrained into the fluid flow path  300  at the fluid inlet  320 . The fluid combines with the processed flow at the second end  34  of the body. In the example shown in  FIG. 2 , the processed flow exits the primary fluid outlet  440  and the hairdryer as an annular flow which surrounds the entrained flow that exits from the hairdryer via the fluid outlet  340 . Thus fluid that is processed by the fan unit and heater is augmented by the entrained flow. 
         [0047]    Referring now to  FIGS. 3 a , 3 b    and  4  which shows the primary inlet area in more detail, a device  100  for distributing wires  102 ,  104  has a central hub  110  which houses the cable  50  and a pair of arms  120 ,  122  which house the wires  102 ,  104  as they are routed from the central hub  110  towards an inner wall  220  of the handle  20  of hairdryer  10 .  
         [0048]    The inner wall  220  has a greater diameter than the central hub  110  so the wires  102 ,  104  with the arms  120 ,  122  extend from the central hub  110  radially outwards towards the inner wall  220  forming a generally “Y” shaped device  100 . 
         [0049]    Referring to  FIG. 4  in particular, the inner wall  220  is formed from two parts  220   a,    220   b;  this simplifies assembly of the parts that are housed within the inner wall  220 . For example parts such as the fan unit  70  and wires  102 ,  104  may be placed within one of the two parts of the inner wall  220  then when all the parts are aligned correctly, the two parts of the inner wall  200  may be joined together to form an inner handle of the hairdryer  10 . 
         [0050]    The wires  102 ,  104  are housed within the arms  120 ,  122  which can be hollow shells but are alternatively solid with recesses adapted to accommodate a wire passing through the arm. 
         [0051]    Referring to  FIG. 5  in particular, the inner wall  220  includes a pair of recesses  224 ,  226  which in this example are partly formed in each of the two parts of the inner wall  220   a,    220   b  and when the two parts of the inner wall  220   a,    220   b  are assembled the pair of recesses  224 ,  226  are created to house the wires  102 ,  104 . Thus, the wires  102 ,  104  are protected from being snagged or caught and are safely out of the fluid flow path  400  where they would cause some disruption to the flow of fluid. 
         [0052]    The cable  50  includes a live wire  104  and a neutral wire  102 . The neutral wire  102  passes from the device for distributing wires  100  and into one of the recesses  226  and live wire  104  also passes from the device for distributing wires  100  and into a second recess  224 . 
         [0053]    Referring to  FIGS. 2, 3   a  and  5  to  7  in particular, the fan unit  70  is supported within the inner wall  220  by two annular seats which retain the motor longitudinally within the inner wall  220  and thus the handle  20 . The recesses  224 ,  226  could continue  passed the fan unit  70 , however in this embodiment, the recesses  224 ,  226  are discontinued where they meet the first annular seat  242 . Both the neutral wire  102  and the live wire  104  are routed from their respective recesses  224 ,  226  radially around the inner wall  220   a  and then longitudinally along a pair of channels  240  formed within the inner wall  220   a.  The pair of channels  240  is designed to receive the live wire  104  and the neutral wire  102  and hold those wires in place around the fan unit  70 . 
         [0054]    In order to fit the wires  102 ,  104  within the inner wall  220 , the inner wall  220  is has a greater thickness t 1  in the vicinity of the wires  102 , 104  compared to the thickness t 2  of the inner wall  220  diametrically opposite the wires  102 ,  104 . The thickness of the inner wall  220  may also vary along the length of the fan unit  70 . 
         [0055]    The inner wall  220  has an outer surface  230  having a central axis E and an inner surface  232  having a central axis F. Axes E and F are different thus the fluid flow path  400  does not flow centrally through the inner wall  220  or the handle  20  of the hairdryer. The fan unit  70  is disposed approximately centrally of the inner surface  242  of the inner wall  220  within motor mount  72 . The central axis M of the fan unit  70  is substantially the same as the central axis F of the inner surface  232  of the inner wall  200 . The central axis M of the fan unit is offset with respect to the central axis F of the outer surface  230  of the inner wall  200  and the central axis W of the outer wall  200 . 
         [0056]    Having a variable thickness in the inner wall  220  along with a fan unit  70  and fluid flow path  400  which are off-centre within the outer wall  200  of the handle  20  means that the diameter of the outer wall  200  of the handle  20  can be reduced compared to the diameter that would be required if all those components were axially aligned, for example by having a constant thickness around the circumference of the inner wall  220 . 
         [0057]    Upstream of the fan unit  70  is a control switch  62 . In order to simplify the wiring within the hairdryer, the control switch  64  is approximately radially disposed in line with the pair of channels  240 .  
         [0058]    The invention has been described in detail with respect to a hairdryer however, it is applicable to any appliance that draws in a fluid and directs the outflow of that fluid from the appliance. 
         [0059]    The appliance can be used with or without a heater; the action of the outflow of fluid at high velocity has a drying effect. 
         [0060]    The fluid that flows through the appliance is generally air, but may be a different combination of gases or gas and can include additives to improve performance of the appliance or the impact the appliance has on an object the output is directed at for example, hair and the styling of that hair. 
         [0061]    The invention is not limited to the detailed description given above. Variations will be apparent to the person skilled in the art.