Abstract:
The invention discloses a hand blender with a built-in 2-speed gearbox with its output shaft rotating clockwise whenever the motor rotates clockwise or anticlockwise, by means of a differential transmission assembly and a one-way bearing, two different output speeds are realized. Thus, different food can be processed with different stirring speeds, and single type of food can be processed with different stirring speed in different mixing stage of a stirring process.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a hand-held blender, and in particular to a hand blender with a built-in 2-speed gearbox which can outputs two different speeds coaxially. 
         [0002]    Hand-held food blenders become more and more popular because of the compact size and convenient to use. Almost hand blenders have one stirring speed, cannot meet the demand on stirring of different food because rotate speed is not high enough or too low. In the process of stirring, it is more suitable to stir in low speed for some material after high speed blending in order to achieve better taste and nutritive value, conventional design cannot meet the demand. 
         [0003]    In addition, the patent application made in China, whose publication number is CN1697622 discloses a hand blender. The output shaft and input shaft of hand blender are not set in the same straight line, only through driving gear broadside engage with driven gear, to realize reducing speed function, the defect of this structure is transmitting instability, and if want to achieve large transmission ratio while enlarge diameter of gear, it is necessary to increase the volume of housing, especially increase radial of the housing, therefore also wasting space of interior housing. 
       BRIEF SUMMARY OF THE INVENTION 
       [0004]    The present invention provides an improved hand blender with a built-in 2-speed gearbox. 
         [0005]    A hand blender with a built-in 2-speed gearbox includes 
         [0006]    a housing; 
         [0007]    a stirring tool; 
         [0008]    a motor secured in the housing; 
         [0009]    an input shaft connected to the motor and configured to rotate synchronously with the motor; 
         [0010]    an output shaft meshing with the stirring tool and configured for outputting power to the stirring tool; 
         [0011]    a gearbox meshing with the input shaft and the output shaft and configured for driving the output shaft to rotate in a first direction with a first speed when the motor rotate in the first direction and for driving the output shaft to rotate in the first direction with a second speed when the motor rotates in a reverse direction. 
         [0012]    An improvement of the above scheme, the input shaft and output shaft are coaxially arranged, the gearbox comprises a constant transmission assembly, the constant transmission assembly is a one-way bearing I, the inner ring and the outer ring of the one-way bearing I are respectively engaged with the input shaft and the output shaft and are rotated coaxially therewith: The rollers of the one-way bearing I slip or free-wheel when the inner ring rotates in a second direction opposite to the first direction. 
         [0013]    A further improvement of the above scheme, the upper end of the output shaft defines a counter bore, the outer ring of the one-way bearing I is fixed in the counter bore. 
         [0014]    A further improvement of the above scheme, the gearbox comprises a differential transmission assembly engaged with the input shaft and the output shaft; the differential transmission assembly is configured to transmit power to the output shaft when the motor rotates in a second direction that is opposite to the first direction, permitting the output shaft to rotate in the first direction with the second speed that is slower than the first speed. 
         [0015]    A further improvement of the above scheme, the differential transmission assembly comprises: 
         [0016]    a sun gear which is sleeved on the input shaft and rotates along with the input shaft; 
         [0017]    an annular gear fixed in the housing: 
         [0018]    a planet gear set received in the annular gear and directly engaged with both the sun gear and the annular gear; 
         [0019]    a planetary carrier for holding the planet gear set; 
         [0020]    an upper transmission turntable which is steady connected with the planetary carrier and rotates synchronously with the planetary carrier; 
         [0021]    an upper bevel ring arranged at a lower end surface of the upper transmission turntable which faces the stirring tool; 
         [0022]    a plurality of bevel gears engaged with the upper bevel ring directly and uniformly distributed circumferentially; 
         [0023]    a bevel gear carrier fixed to the housing and configured for holding the plurality of bevel gears therein, wherein the inner surface of the bevel gear carrier defines a plurality of holes for receiving the fear axes of the plurality of bevel gears; 
         [0024]    a lower transmitting turntable arranged under the bevel gear and sleeved on the output shaft, wherein the upper end surface of the lower transmitting turntable arranges a lower bevel ring which directly engaged with the plurality of bevel gears; and 
         [0025]    a one-way bearing II ( 71 .  75 ) configured at one of the following positions or both of the positions: 1) between the input shaft and the sun gear, and 2) between the lower transmitting turntable and the output shaft; 
         [0026]    wherein the rollers of the one-way bearing II slip or free-wheel when the inner ring of the one-way bearing II is rotated in the first direction. 
         [0027]    A further improvement of the above scheme, the planet gear set comprises 3˜5 planet gears, the planet gears are all circumferential distributed uniformly in the lower end surface of the planetary carrier by their vertical spindles. 
         [0028]    A further improvement of the above scheme, a plurality of fixed pins fixes the planetary carrier and the upper transmission turntable to realize rotating synchronously between the planetary carrier and the upper transmitting turntable. 
         [0029]    A further improvement of the above scheme, the fixed pins are vertical spindles stretching downward and penetrating fixedly into the interpenetrating holes preinstalled in the planetary carrier. 
         [0030]    A further improvement of the above scheme, the number of the bevel gears is 3˜5, the bevel gears are arranged in the bevel gear carrier by its fear axes, the fear axes are mutually perpendicular to the output shaft. 
         [0031]    A further improvement of the above scheme, the lower end of the output shaft is provided with a connector which is butt jointed with the stirring tool. 
         [0032]    An further improvement of the above scheme, an upper end cover and a lower end cover are configured under the motor and above the connector, respectively. 
         [0033]    The present invention has the following beneficial effects: 1. the present invention through coordinating of constant transmission assembly and differential transmission assembly, hand blender can realize coaxially outputting two different speed in same direction, that is the same stirring connector can achieve two different rotational speed. Not only can it satisfy different food need different stirring speed, but also satisfy the same food need different stirring speed in different mixed phase during stirring process, therefore it has obvious progress; 2. Because of the hand blender in present invention output two speed are identical in rotational direction, therefore the connector has better adaptability and better flexibility when it match different stirring tool or cutting tool, it do not require changing standard design of accessories because of two speed output in different direction, such as direction of turning for blades of stirring tool, the direction of turning for blades of cross cutting tool, and the direction of turning for blades of squeeze screw etc. 3. The vertical integration and composite structure of constant transmission assembly and differential transmission assembly in present invention, and arranged in the housing s well the motor, to realize linear transmission coaxially, therefore it greatly save space, reduce volume of the machine, and compact structure, ensure transmitting stability. 4. When stirring hot food or hot liquid, switching to stir in low speed, which can avoid danger about hot food or hot liquid fly out. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a perspective view of a hand blender of the present invention. 
           [0035]      FIG. 2  is an exploded view of the hand blender according to a first embodiment. 
           [0036]      FIG. 3  is a cross-section view of a hand blender according to a first embodiment of the present invention. 
           [0037]      FIG. 4  is a cross-section view of a hand blender according a second embodiment of the present invention. 
           [0038]      FIG. 5  is a cross-section view of a hand blender according to a third embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0039]    Embodiments of the present disclosure will now be described in detail below with reference to the accompanying drawings. 
       Embodiment I 
       [0040]    As shown in  FIGS. 1-3 , a hand blender with a built-in 2-speed gearbox according to a first embodiment of the present invention includes a housing  1 , a motor  2  arranged in the housing  1 , an input shaft  3  with synchronous rotation with the rotor of motor  2 . an output shaft  4  for outputting power to a stirring tool, an upper end cover  9  configured under the motor in the housing, a lower end cover  10  arranged above the connector and in the housing, a constant transmission assembly  5 , a differential transmission assembly  6 , and a connector  8 . The constant transmission assembly  5  and the differential transmission assembly  6  are arranged between the input shaft  3  and the output shaft  4 , and are configured to drive the output shaft  4  to rotate clockwise whenever the motor rotates clockwise or anticlockwise. The connector  8  is set at the lower end of the output shaft  4  and engages with the stirring tool. The output shaft and the input shaft are coaxially arranged. The constant transmission assembly  5  is a one-way bearing I which is locked when rotates clockwise. The inner ring and the outer ring of one-way bearing I respectively engages with the input shaft and the output shaft and rotate coaxially. The one-way bearing I is locked when rotates clockwise means that the one-way bearing I transmits rotation to the output shaft  4  when the input shaft rotates clockwise, and the rollers of the one way bearing I slip or free-wheel when the inner ring rotates anticlockwise thus cannot transmit rotation to the output shaft. The upper end of the output shaft defines a counter bore  41 , the outer ring of the one-way bearing I is fixed in the counter bore. The differential transmission assembly  6  includes a sun gear  61  sleeved on the input shaft and capable of rotating clockwise along with the input shaft, a planet gear set  62  engaging with the sun gear, and a planetary carrier  63  for receiving the planet gear set. The planet gear set  62  constitute of 3˜5 planet gears, the planet gears are all circumferential distributed uniformly in the lower end surface of the planetary carrier via vertical spindles  72 . The vertical spindles  6  are downward stretch and penetrate fixedly into interpenetrating holes  73  defined in the planetary carrier  63  to form fixed pins. 
         [0041]    The planetary carrier  63  is fixed and rotated synchronously with an upper transmission turntable  64 . An upper bevel ring  65  is configured at the lower end surface of the upper transmitting turntable  64 . The upper bevel ring  65  direct engages with a plurality of bevel gears  66  which are circumferential distributed uniformly. A Lower transmitting, turntable  67  is arranged under the bevel gear, the upper end surface of the lower transmitting turntable  67  arrange a lower bevel ring  68  which direct engages with the bevel gears, the lower transmitting turntable  67  is sleeved on the output shaft. The planet gear set  62  direct engages with an annular gear  69  fixed in the housing. The bevel gears are arranged in the bevel gear carrier  70 , the bevel gear carrier is fixed in the housing, The number of the bevel gears may be three to five, and the bevel gears are arranged in the bevel gear carrier via a plurality of fear axes  74 . The vertical spindle  74  and the output shaft  4  are mutually vertical. Between the lower transmitting turntable and the output shaft arrange a one-way bearing II  71  which is locked when driven anticlockwise. 
         [0042]    The motor  2  drives the input shaft  3  to rotate, when the input shaft  3  rotates clockwise ′ the power is transmitted to the output shaft  4  by the one-way bearing I which is locked, the output shaft  4  drives an agitator arm connected with the connector  8  to rotate clockwise, the connector  8  can detachably connect different machining tools such as a stirring tool, a cutting tool, etc. Besides, the input shaft  3  drives the differential transmission assembly  6  to rotate, in details the sun gear  61  rotates clockwise ′ thus drives the planet gear set  62  to rotate clockwise, the annular gear  69  rotate along with the planet gear set  62 , the upper transmitting turntable  64  integrated with the planet gear set  62  and the upper bevel ring  65  also rotate clockwise. The bevel gears  66  transmit power to the lower bevel ring  68 , making the lower transmission turntable  67  rotates anticlockwise, thus the rollers of the one-way bearing II  71  slip or free-wheel, and power cannot be transmitted to the output shaft  4 , therefore, the input speed and the output speed ratio is 1:1. 
         [0043]    When the input shaft  3  rotates anticlockwise, the rollers of the one-way bearing I slip or free-wheel, power cannot be directly transmitted to the output shaft  4 . At the moment, the input shaft  3  drives the sun gear  61  to rotate anticlockwise, the sun gear  61  thus drives the planet gear set  62  to rotate, the annular gear  69  rotates with the planet gear set  62 , the upper transmitting turntable  64  integrated with the planet gear set  62  and the upper bevel ring  65  also rotate anticlockwise. The bevel gear  66  transmits power to the lower bevel ring  68 , to make the lower transmitting turntable  67  rotating clockwise, power is transmitted to the output shaft  4  by the one-way bearing II  71  which is locked, and an output speed is smaller than an input speed. Thereby realizing the blender coaxially outputs two different speeds in the same direction by the clockwise and anticlockwise rotation of the input shaft. 
       Embodiment II 
       [0044]    As shown in  FIG. 4 , the structure of the hand blender with a built-in 2-speed gearbox revealed in this embodiment is similar to the structure of that in the embodiment II, the difference lies on that, the one-way bearing II  75  is arranged between the input shaft  3  and the sun gear  61 , and is locked when being driven anticlockwise. While the one-way bearing II  71  is omitted and is not arranged between the lower transmitting turntable  67  and the output shaft  4 , the lower transmitting turntable rigidly connects with the output shaft When the input shaft  3  rotates clockwise, the one-way bearing II  75  rotates freely, the driving force of the input shaft  3  cannot transmit to the differential transmission assembly  6 , power is transmitted to the output shaft  4  via the one-way bearing I, to make the output shaft  4  rotating clockwise in transmission ratio 1:1. The output shaft  4  drives the differential transmission assembly  6  rotating through the lower transmitting turntable  67 , power is transmitted to the sun gear  61  from the bevel gear  66 , the upper transmitting turntable  64  and the planet gear set  62 , sun gear  61  rotates anticlockwise and drives the outer ring of the one-way bearing II  75  rotating anticlockwise, thus the rollers of the one-way bearing II  75  slip or free-wheel, the sun gear cannot transmit power to the input shaft  3 , avoid causing dynamic interference. At the same time, the output shaft  4  drives the agitator arm connected with the connector  8  to rotate, the connector  8  can detachably connect different machining tools such as a stirring tool, a cutting tool, etc. 
         [0045]    When the input shaft  3  rotates anticlockwise, the rollers of the one-way bearing I slip or free-wheel ′ power is not directly transmitted to the output shaft  4 . At the moment, the input shaft  3  drives the differential transmission assembly  6  rotating through the one-way bearing II  71  in details the sun gear  61  rotates anticlockwise, the sun gear  61  drives the planet gear set  62  rotating, the annular gear  69  rotates with the planet gear set  62 , the upper transmitting turntable  64  integrated with the planet gear set  62  and the upper bevel ring  65  also rotate anticlockwise. Power is transmitting to the lower bevel ring  68  through the bevel gear  66 , to make the lower transmitting turntable  67  rotate clockwise, thereby the lower transmission turntable  67  drives the output shaft  4  to rotate clockwise, the output speed is smaller than the input speed of the input shaft. Thereby realizing the blender coaxially outputs two different speeds in the same direction by the clockwise and anticlockwise rotations of the input shaft. 
       Embodiment III 
       [0046]    As shown in  FIG. 5 , the structure of the hand blender with a built-in 2-speed gearbox revealed in this example is similar to the structure of that in the embodiment I, the difference lies on that, between the input shaft and the sun gear, and between the lower transmitting turntable and the output shaft respectively arrange a one-way bearing II ( 71 ,  75 ), the one-way bearing II  75  is locked when driven anticlockwise, when the input shaft  3  rotates clockwise, power is transmitted to the output shaft  4  through the one-way bearing I the output shaft  4  drives the rabble connected with the connector  8  to rotate, the connector  8  can connect different machining tools detachably such as a stirring tool, a cutting tool, etc. At the moment, the differential transmission assembly  6  rotates freely because the one-way bearing II  75  which is locked when rotating anticlockwise, the driving force of the input shaft  3  is not transmitted to the differential transmission assembly  6 , result that the differential transmission assembly  6  do not rotate, thereby saving power, delaying the working life of the drive parts, the input speed and the output speed ration is 1:1. 
         [0047]    When the input shaft  3  rotates anticlockwise, because the one-way bearing I rotates freely, power is not directly transmitted to the output shaft, at the moment, the input shaft  3  drives the differential transmission assembly  6  to rotate via the one-way bearing II  75  which is locked. In details the sun gear  61  rotates anticlockwise, the sun gear  61  drives the planet gear set  62  to rotate, the planet gear set  62  and the annular gear  69  also rotate, the upper transmitting turntable  64  integrated with the planet gear set  62  and the upper bevel ring  65  also rotate anticlockwise, power is transmitted to the lower bevel ring  68  through the bevel gears  66 , to make the lower transmitting turntable  67  rotating clockwise, power is transmitted to the output shaft  4  through the one-way bearing II  71  which is locked, the output speed is reduced compared to the input speed of the input shaft. Thereby realize blender coaxially outputting two different speeds in the same direction by input shaft rotates clockwise or rotate anticlockwise. 
         [0048]    The above examples is better implementation model in the represent invention, it should be explained that, without departing from the spirit of the present invention and its substantial technical, such as the number of planet gear set or the number of bevel gear, the direction of rotation of gear and output shaft, and the location of one-way bearing or self-locking direction etc, those skilled in the art are able to make various corresponding changes and modifications according to the present invention, but these respective changes and modifications shall fall within the scope of protection of the present invention.