Abstract:
A mixer assembly having vertically displaced differential agitators. The first agitator is a primary mixing component formed of a hub having slots for positioning and securing radially extending angularly displaced stirring members. The hub is of a unitary construction and has three arcuate generally convex sidewalls attached about a central bore for receiving a drive shaft. The spaces between vertically extending edges of the sidewalls form the slots into which the stirring members are pivotally attached. The second agitator is a secondary mixing component formed of a disc shaped retaining member with stirring members angularly displaced about the edge of the disc. The stirring members of both the first and second agitators extend horizontally with rotation of the drive shaft, with the first agitator effective for both loosening sediment and stirring, while the second agitator increases the stirring effect. A separate detached component is used to remove excess liquid from the drive shaft when the mixing action is completed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates generally to mixer assemblies. In particular, the present invention is directed to a mixer assembly having two stages, with each stage having different operational characteristics. 
         [0002]    Mixer assemblies for mixing liquids of various viscosities have been available for many years. Typically such mixers have a drive shaft extending from and operationally connected to a source of motive power, and an agitator or stirring component shaped to effect a particular mixing result. In the case of paints and chemicals stored in cans and large drums, mixers tend to have an elongated shaft to enable positioning the stirring component laterally within the confines of the container holding the substance to be mixed, and more importantly vertically so that the contents of the bottom of the container can be stirred. This vertical displacement capability is of increased importance with high viscosity materials as some settling of the material will typically occur. While some prior art devices are reasonably effective for their intended purpose, they tend to suffer from drawbacks. First, the agitator component tends to be either rigid or flexible, with the drawback being that a rigid agitator e.g. blades or paddles will tend to be affected by coming into contact with the sides of the container. This is especially true when the mixer is powered by a small drill or the like which has limited torque when applied to a long shaft. Flexible agitators tend to have limited effectiveness with heavy sediment which can collect at the bottom of, e.g., a can of paint. Also, especially in the case of an elongated shaft, a considerable amount of the product mixed will remain on the shaft and agitator after mixing, and this product will drip onto the surface supporting the can or drum which both wastes product and can have a deleterious effect on the surface. 
         [0003]    U.S. Pat. No. 5,941,636 issued to one Lu is an example of a typical drill powered mixer assembly. The assembly has three vertically displaced agitators, each having two opposing, generally rigid blades. The blades, which are pivotally attached to the shaft with a retainer, extend horizontally upon rotation of the shaft. The drawback is that the rigid agitators are subject to heavy friction when in contact with the sides of the container, which slows the mixer and limits effectiveness. Also, while rigid, the small blades are not sturdy enough to break up deposits which may collect on the bottom of the container. 
         [0004]    U.S. Pat. No. 7,329,040 issued to Elrod is a drill powered mixing assembly having a single agitator composed of a two link chain. The relative short chain connected close to the drive shaft provides very little angular momentum and again is not effective at removing and stirring deposits. 
         [0005]    None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention overcomes the disadvantages of the prior art by providing a mixer assembly having vertically displaced differential agitators. The first agitator is a primary mixing component formed of a hub having slots for positioning and securing radially extending angularly displaced stirring members. The hub is of a unitary construction and has three arcuate generally convex sidewalls attached about a central bore for receiving a drive shaft. The spaces between vertically extending edges of the sidewalls form the slots into which the stirring members are pivotally attached. The second agitator is a secondary mixing component formed of a disc shaped retaining member with stirring members angularly displaced about the edge of the disc. The stifling members of both the first and second agitators extend horizontally with rotation of the drive shaft, with the first agitator effective for both loosening sediment and stirring, while the second agitator increases the stirring effect. Both stifling members are hingedly attached to create a whipping effect which increases stirring velocity. A separate detached component is used to remove excess liquid from the drive shaft when the mixing action is completed. 
         [0007]    Accordingly, it is a principal object of the invention to provide an improved mixer assembly. 
         [0008]    It is another object of the invention to provide an improved mixing assembly having two differential, vertically displaced agitators. 
         [0009]    It is another object of the invention to provide an improved mixing assembly having a first, more robust agitator for mixing at the bottom end of a container, and a second agitator for increasing stirring velocity. 
         [0010]    Finally, it is a general object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
         [0011]    These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0013]      FIG. 1  shows a perspective view of the mixing assembly of the invention. 
           [0014]      FIG. 2  shows a plan view of the first mixing component of the assembly. 
           [0015]      FIG. 3A  shows a perspective view of the first mixing component with the stirring elements attached. 
           [0016]      FIG. 3B  shows a perspective view of the first mixing component detailing the adjustment mechanism. 
           [0017]      FIG. 4  shows a perspective view of the first mixing component with the stirring elements removed. 
           [0018]      FIG. 5  is a perspective view of the second mixing component. 
           [0019]      FIG. 6  is a side view of the second mixing component. 
           [0020]      FIG. 7  is a perspective view of a retaining disc used with the second mixing component 
           [0021]      FIG. 8  is a perspective view of the product removal component of the invention. 
           [0022]      FIG. 9A  is a plan view of a gasket used with the component of  FIG. 8 . 
           [0023]      FIG. 9B  is a perspective view of a gasket used with the component of  FIG. 8 . 
           [0024]      FIG. 10  is a perspective view of the second mixing component attached to a drive shaft. 
           [0025]      FIG. 11A  shows a perspective view of an alternative construction for the second mixing component. 
           [0026]      FIG. 11B  shows a perspective view of an attachment member used in the alternative construction for the second mixing component 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    Referring now to  FIGS. 1-10 , the inventive assembly, generally indicated by the numeral  10 , is shown. With particular reference to  FIG. 1 , it can be seen that the assembly  10  includes an elongated drive shaft  12  having a geometric, usually pentagonal cross section having an end portion sized for locking fit within the drill bit receiving clamp  15  of a drill  13 . The shaft  12 , which is made of metal or other rigid, high strength durable material, may have a round, oval or other cross sectional shape provided it has an end portion sized and shaped to be securely clamped by a drill or other rotary source of motive power. While the invention  10  is described as being implemented by a power drill, any source of rotating motive power may be used. 
         [0028]    A key aspect of the invention  10  is its ability to be effectively employed to mix or stir liquids of various viscosities. To that end, a pair of agitators or mixing components are utilized, preferably in tandem for most mixing applications. The first mixing component  20  is formed of a robust hub portion  22 , with a plurality of, in this case three, stifling elements  23  hingedly attached thereto, in angularly spaced relation as will be explained in more detail below. Referring now particularly to  FIGS. 2-4 , the hub  22  is formed of metal or other durable high strength material and is preferably of a unitary construction. Hub  22  is securely attached to the shaft  12  using any suitable attachment means such as welding, the attachment means serving to prevent rotation of the hub  22  relative to the shaft  12  as well as vertical displacement. The attachment means may be a conventional set screw assembly which allows for removal or vertical adjustment of the hub  22 . The assembly consists of the set screw  23  and threaded bore  27  formed in the hub  22 , the screw threaded into the bore until abutting the shaft  12 . Alternatively a roll pin  25  may be inserted into bore  27 , which is axially aligned with a bore extending into the shaft  12 . Of course any set screw or vertical adjustment assembly known to one of skill in the art may be employed. A central shaft receiving bore  24  allows for positioning the hub  22  on the shaft  12  where it can be attached as discussed above. It can be seen that the hub  22  has three arcuate, generally convex wall portions  26  which extend from the central shaft receiving portion  28 . The opposing horizontally displaced edge regions  30  of adjacent wall portions  31  protrude in a radial direction in parallel spaced relation from central portion  28  at 120 degree intervals to form three vertically disposed slots  32 . Each edge region  30  has a small bore  34  formed therein approximately midway vertically, the mutually opposing bores  34  axially aligned to allow for positioning a small rivet or bolt  36  therethrough. The bolt  36  serves as an anchoring or attachment point for stirring elements  23 . The protruding wall portions  31 , which are essentially limited radius blades, also function to dislodge heavy sediment from the bottom of the container. 
         [0029]    The stirring elements  23  are formed from a chain made of metal or other durable material and preferably having at least two double loop links. While more or fewer links may be used, the two double loop link configuration is optimal for mixing. Also, the size of the double loop links are varied depending upon the size of the mixer, that is, a larger mixer will require larger links to produce a horizontal rotational plane of a larger diameter. In accordance with one aspect of the invention, it is preferable to use larger double loop links to increase the diameter of the rotational plane, as opposed to adding more links of a smaller size to increase the diameter of the rotational plane. A larger mixer is desirable when mixing the contents of a large, e.g., 55 gallon drum, container. It can be appreciated that a larger and deeper container will require a longer shaft  12  and a commensurately larger mixing component  20 . 
         [0030]    The connecting loop  40  of the first two loop link is hingedly attached to the hub  22  so that the elements  23  are freely hanging from the hub  22  when stationary so that the component  20  can be pushed through a bung hole in a container as will be discussed in more detail later. The loop  40  is attached to the hub  22  via bolt  36  within cooperating slot  32 , and is permanently oriented vertically widthwise during rotation, that is, the opposing sides  42 ,  44  of the loop  40  are vertically disposed as the end portion  46  of the loop  40  is “pinched” within the slot  32  to limit rolling or wobbling of the loop  40 . This permanent vertical orientation, combined with the radial spacing (from the shaft) of the element  23  due to the configuration of the hub  22 , increases spin velocity by increasing the minimum radius of the element  23  relative to the shaft  12  during rotation as shown particularly in  FIG. 2 . Also, this configuration prevents wrapping of the elements  23  around the shaft  12  which can occur when heavy sedimentation slows rotation of the shaft  12 , and creates a whipping effect which increases stirring velocity. The other loops  48 , of which there are at least three, are hingedly attached in a fashion normally used for chains, using the two double loop link configuration as discussed above. 
         [0031]    Referring now particularly to  FIGS. 5-7 , and  10 , the second mixing component  50  is shown. This mixing component  50  is especially useful for low viscosity liquids and/or shallow containers. The second component  50  is not as aggressive as the first component and may be used as the sole mixing component when mixing low viscosity liquids and/or liquids contained in shallow containers to prevent spraying of the liquid outside of the container. 
         [0032]    The component  50  is in two parts. The first part is a disc shaped flange or hub  52  which can be securely attached to the shaft  12  using any suitable attachment means such as welding, the attachment means serving to prevent rotation of the flange  52  relative to the shaft  12  as well as vertical displacement. The flange  52  can alternatively be adjustably and removably positioned on the shaft  12  using either a conventional set screw or roll pin assembly  53 ,  55 , either of which is adapted to fit within slot  57  in the manner as described above. The flange  52  is formed of metal or other rigid, durable material. Three slots  54 , angularly displaced by  120  degrees function as attachment points for each of the three stifling elements  58 . The second part of the component  50  are the stirring elements  58 , which are in the form of a chain having preferably two double loop links as per the above discussion. The effective radius of the elements  58  is increased by increasing the size of the double loop links. The connection loops  60  are looped within the slots  54  and are essentially hingedly attached to the flange  50  when the component is stationary (i.e., not rotating under motive power). When rotating however, connection loops  60  are locked onto the hub  52 , more or less vertically disposed as described above, but in angular relation relative to the shaft  12  as can be seen in  FIG. 5 . This “locking” action, which is effected by centrifugal force, increases spin velocity via a whipping effect as described above and shown in  FIG. 5 , and also reduces the occurrence of the element  58  becoming wrapped around the shaft  12 , as the connection loop  60  is essentially locked in place on the hub  52 . 
         [0033]    As previously stated, the invention  10  has utility for mixing liquids of various viscosities. To that end the combination of mixing components  20 ,  50  positioned on the shaft  12  is selected in accordance with the viscosity. For a low viscosity fluid, a single component  50  is preferably used, the component  50  attached at the end of the shaft  12 . If the low viscosity fluid is in a large container it would of course be advantageous to use two vertically spaced components  50  vertically spaced on the shaft  12 . For medium viscosity fluids such as paints, where some sedimentation may occur, both components  20 ,  50  may be positioned on the shaft  12  as shown in  FIG. 1 , with component  20  serving to break up sedimentation and component  50  serving to provide increased stirring throughout the container. For very high viscosity products such as drywall mud, two of the components  20  may be arranged on the shaft  12  in vertically spaced relation, the vertical spacing adjusted in accordance with the depth of the container. It can be appreciated that for a shallow container only a single component  20  or  50  would be appropriate, with either component  20  or  50  deployable in tandem. 
         [0034]    In use, the components  20  or  50  are positioned on the shaft  12  in the appropriate configuration in accordance with the liquid or product to be mixed as discussed above. Both components  20 ,  50  are sized for insertion into a bung hole or other mixing hole in a container for the product to be mixed. The drill  13  or other source of motive power is activated causing the stirring elements  23  and/or  58  of components  20  or  50  to extend in a horizontal plane to effect mixing of the product. The shaft  12  can be manipulated vertically and horizontally to effect mixing of the entire contents of the container in a manner well known in the art. When the mixing action is completed the shaft  12  is removed from the container, and preferably positioned in a container of water or solvent to remove product from the shaft  12  and mixing components  20 ,  50 . 
         [0035]    Removal of the shaft  12  from the container will ordinarily result in some of the liquid or product dripping onto the support surface upon which the container rests. To that end, a containment tube  70  is provided. The tube  70  expedites the removal process as most of the excess product can be effectively “squeegeed” from the shaft  12 . The tube  70  is essentially cylindrical and includes a slot  72  allowing for insertion of the shaft  12 . A partial gasket member  74  is inserted into one end of the tube  70  as by frictional fit, and is preferably at least somewhat compressible. Alternatively, the gasket  74  may be glued or otherwise attached to the tube  70 . The partial gasket  74  has an angled guiding slot  76  formed therein, the slot terminating in an orifice  78  sized to snugly and slidably receive the shaft  12 . In use, the shaft  12  is positioned within the tube  70  with the proximal end  80  of the shaft positioned within orifice  78 . The tube  70  is then slid down the shaft  12  to squeegee product from the shaft  12 , the outer surface of the tube serving to maintain the users hand a distance away from the product. 
         [0036]    Referring now to  FIGS. 11A and 11B , an alternative construction for the second component is shown. The component  61  is formed using injection molding techniques and is permanently attached to a shaft  62 . An attachment member  63  having three triangular flanges  64  is molded directly onto the end of the shaft  62 . A flange  52  is prepared for insertion onto attachment member  63  by looping connection links into slots  54  as with the previous embodiment. The flange  52  can then be attached to the attachment member  63  using flanges  64  to align the slots  54 , the flanges  64  at least partially seated within the slots  54 . End cap  65  is secured to the end of the attachment member  63  by a quantity of glue or other adhesive, so that end cap  65  is secured to the underside of flange  52 , the flange  52  situated between endcap  65  and attachment member  63 . 
         [0037]    From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions. 
         [0038]    It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims: