US2736537A - Mixing bit - Google Patents

Description

N. NELSSON MIXING BIT Feb. 28, 1956 Filed Sept. 5, 1952 INVENTOR.

United States Patent- MIXING BIT Nels Nelsson, Chicago, Ill. Application September 3, 1952, SerialNo. 307,643 r 2 Claims. (Cl. 259-134) This invention relates to an improved mixer of the revolving blade type and is more particularly concerned with a mixing bit of novel blade construction.

In the mixing of small quantities of thick fluid material such as cements, paints, batters, dough, or the like, it is the usual custom to mix the material by hand with a paddle or to use beaters or other revolving types of mechanical mixers. The mechanical mixers all require. the material to be placed in special containers which are as a rule an integral part of the mixer itself. Further, these mixers frequently cause a great deal of splashing and spillage of material unless care is exercised in carrying out the mixing operation. Most mixers have attached motors which not only add to their cost but also limit their utility.

It is therefore, an object of this invention to disclose a mixing device which can be used in a nearly'full container without any appreciable amount of spillage or splashing. I

It is an object of this invention to set forth a novel type of mixing blade arrangement by which paint or other fluid material in cans may be readily redispersed in situ without any appreciable amount of overflow.

It is an object of this invention to disclose an improved revolving multiple blade type of mixing bit which will bring up solid material in the lower portion of a container and disperse it in the main body of the fluid without any appreciable splashing or waste.

It is an object of this invention to disclose a mixing device which can be revolved by inserting as a bit into an electric drill or any revolving device having a chuck capable of taking a drill or the like.

Various other objects will readily occur to those skilled in the art in which this invention is a part.

This invention is best understood by means of drawings in which:

Figure l is a view of a mixing bit made following this invention inserted into the chuck of an electric drill for the purpose of rotation.

Figure 2 is a sectional view through Figure 3 along the lines 2-2 showing how the blades in each propeller are arranged.

Figure 3 is a side view showing the pitch relation of the top and lower sets of blades shown in Figure 1.

There has long been a need for a simple portable mixer to disperse fluid material while in small cans or containers without splashing, thus doing away with the removal of the material to another container for the purpose. Also, there is need of a mixing device which can be driven by readily available sources of power such for example as a portable electric drill. A mixer such as referred to above is particularly desirable in the paint field. Most paint is sold in one-quart and one-gallon containers. Practically all paints have the serious disadvantage of stratifying into a heavy layer composed of the solid material on the bottom and a fluid layer on the top, predominantly the vehicle. In practice, these paints are usually mixed on the job with a paddle which requires considerable time and results in only a fair degree of mixing. Hence, if a mixer could be devised which could mechanically mix such material in the can itself on the job without undue splashing and without the use of an integral driving means, a decided advance in the painting art would be effected. It is the purpose of this invention to set forth in detail a mixer which will accomplish all of the above objectives.

In carrying out this invention, a vertical shaft of a diameter, such as which can fit into the chuck of an electric drill or drill press is used. To this shaft are attached upper and lower multiple blade, propeller type mixing members of novel pitch arrangement which contribute very markedly to the effective operation of this invention. The relation of the blades to each other is highly important and must be followed in the manner as henceforth described in order to obtain satisfactory results. It is preferred in practicing this invention to use a propeller having at least two individual blades with a space in between, though the propellers can be of other form such as in the shape of a disc which however should be only in the top position. Additional blades can be used if desired, though three are preferred such as illustrated in the figures. The angle of the-blade with a plane extending at right angles through the shaft blade is important and should not vary substantially beyond a minimum of about 10 to a maximum of about and preferably it should be substantially as shown in Figure 3 or about 17 with the horizontal. The angle of the pitch is reversed between the top and bottom propellers. Whenever the propeller operates in a clockwise direction looking down, which is the direction of rotation of most drills, the cutting face of the upper propeller blade extends above the horizontal while in the case of the lower propeller, the cutting face of the blade extends below. It is preferred to have these angles equal but it is not the intention to limit the scope of the invention to equal angles of pitch for there I can be a marked difference in the pitch between that of the upper and lower propeller blades, if such is found expedient. The blades of each propeller are preferably formed in one piece and while they can be welded to the shaft, it is preferred to secure them by means of nuts on either end with a sleeve in between them as shown in Figures 1 and 3. In the figures, 1 is the upper and 2 the lower propeller. The shaft is marked 3, and the sleeve spacing the propeller blades the proper distance is designated 4. The shaft is threaded at the lower end so that nuts can be secured as shown leaving enough space for the end nut 6 tobe inserted. The nut 8 is screwed onto the shaft 3 so as to fix the upper position of the propeller assembly while the nut 6 holds the as sembly at the lower end. The sleeve member 4 placed around the shaft spaces the propellers the proper distance apart. By tightening the nuts firmly against the assembly it will then turn with the shaft. When this bit is attached to the chuck 7 of an electric drill and inserted into a can of paint, the upper blades force all liquid material down while the lower blades dig out the material on the bottom and force it upwards by which ac tion, the entire content of the can is circulated and readily mixed. Since most cans are usually filled brimful, it is obviously desirable to remove a small portion of its content from the top in order to avoid spillage but the liquid level need be only a short distance down from the brim.

As mentioned previously, 2 or more mixing blades can be used in forming each propeller. While three equidistant blades have been shown in the preferred embodiment of this invention, 4, 5, or 6 or even more blades can be used and still be within the ambit of this invention. It is important that the blades and propellers be of such arrangement and shape that the shaft will be substantially balanced. It is very difiicult to balance the blades by any other'rneans than by proper arrangement and design of the blades themselves.

It is an important part of this invention to make the cap nut 6 such that it will act in the nature of an end bearing as it rests on the bottom of the can for otherwise there is the danger of wearing out the can at the bottom, as well as difficulty in handling and positioning the bit properly in the can. This nut should have a spherical contour so as to permit rotation of the shaft while the nut touches the bottom at various angles.

It is also an important part of this invention to have the blades of the upper and lower members staggered so that the center line of the upper blades is above the center of the space in between the lower blades as shown in Figure 2.

Various modifications can be made in the construction of the mixing bits in carrying out this invention and still not depart from its essences. For example, the upper blade can be replaced by a disc, and while the entire assembly is described as being made of metal, a portion or all can be formed from plastics.

When a disc is used to replace the propeller blades it should be the upper member, and preferably of about the same radius as the outer edge of the blades.

Having disclosed an important embodiment of this invention, it is not the intention to be limited thereby, but only in the scope as set forth in the following claims.

It is claimed:

1. A mixing bit comprising a vertical shaft and spaced apart upper and lower mixing members adjacent the lower end of said shaft, each member comprising a plurality of propeller blades spaced equiangularly about and extending radially from said shaft and angularly disposed at an angle no greater than about 30 with respect to a plane extending at right angles to said shaft such that the leading edge of each of said blades constituting the upper member is above the trailing edge when said shaft is revolved in a clockwise direction, and the leading and trailing edges of said lower member being in opposite relation to said upper member, the blades of both mixing members having substantially the same equiangular spacing, the blades of one member being opposite the angular space between the blades of the other member and the outer portion of the leading edge of each of said propeller blades curved from the shaft in a direction contra to that of the direction of rotation.

2, A mixing bit for the highspeed mixing of a fluid in a container with substantially no splashing, comprising a vertical shaft and spaced apart upper and lower mixing members adjacent the lower end of said shaft, each member comprising a plurality of propeller blades spaced equiangularly about and extending radially from said shaft and angularly disposed with respect to a plane extending at right angles to said shaft such that the leading edges of the said propeller blades in the said upper mixing member are in divergent relation to the leading edges of the said propeller blades in the said lower mixing member and the corresponding trailing edges of the propeller blades of said mixing members extending more towards a convergent relationship than said leading edges, the leading edge of each propeller blade curved so that the outer point of said edge trails that of the inner point adjacent the shaft, the blades of both mixing members having substantially the same equiangular spacing and the blades of one member being opposite the angular space between the blades of the other member.

References Cited in the file of this patent UNITED STATES PATENTS (1st addition to No. 795,933)

Images