US2208955A - Agitator for domestic mixers - Google Patents

Description

July 23, 1940. R. c. WOLFF AGITATOR FOR DOMESTIC MIXERS Filed Feb. 11, 1939 INVENTOR Roe/5R7 C. 6004;;

VIII/I Patented July 23, i940 rte 6 Claims.

This invention relates to domestic mixers and has particular reference to a mixer of the type having a structure embodying a driving motor and one or more removable agitators, such mixers being conventionally employed in accomplishing a wide variety of culinary mixing operations.

In such devices the agitating elements are usually removably associated with the machine so that they may be taken out for cleaning purposes or for the purpose of introducing agitators of another type or other implements for accomplishing other purposes. While conventional agitators are constructed so that they may be removed from the machine, this alone does not sufficiently facilitate cleaning thereof. The arrangement of the parts of agitators of this class is such that it is quite difficult to adequately clean all portions of an agitator.

One object of my invention resides in the provision of an agitator which is not only susceptible of removal from the machine proper but one which may be itself readily dismantled so that the component parts may be conveniently and. thoroughly cleaned. In the device of my invention such dismantling may be accomplished quickly and without the employment of tools, special or otherwise.

In agitators of the class under discussion and according to present practices in the art, there are usually found metal bands formed into loops and a pair of such loops are disposed at right angles to each other and so that they are in engagement with each other or at least in close proximity at diametrically opposed points. The two loops are permanently fixed to a drive shaft which conventionally engages the assembled loops at both of their points of engagement. In some conventional machines two agitator assemblies of the foregoing description are employed and when this is the case the shafts are held in the machine in parallel relation to each other and spaced a distance less than the width of the loops so that the agitating loops of one agitator havea sort of meshing action with respect to the loops of the other agitator without, however, coming into actual contact therewith.

The use of the expression diametrically opposed herein is not to be taken as an inference that the loops are necessarily circular, in fact that may bebut is not usually the case. By diametrically opposed I mean disposed at opposite points on the loop, points on the loop equidistant from each other either way around the loop.

A further marked advantage which is attained in the device of my invention is found in the fact that agitators made in accordance with the principles thereof may be used with both agitator loops in their usual assembled position or one only of the agitator loops may be used without the other. While at first blush it may appear that the mixing action resulting from the use of only one loop would be merely a slower mixing, comparable to reduction of the driving speed of agitators carrying two loops, such is actually not the case.

A closer examination of the question shows that the singe loop of the agitator is traveling through the material being mixed at the same speed as when two loops were used but that the agitations in any given part of the material do not follow each other at the same rate of speed as with two loops. Tests have shown that the facility for removing one agitator loop from an agitator element and using the other alone increases the scope of application of the device and resultsin a more beneficial mixing action in a variety of specific mixing problems.

While several specific embodiments of the principles of the present invention have been illustrated in the drawing and are set forth in detail in the following description, it is to be understood that my invention is only to be considered as limited by the appended claims.

In the accompanying drawing:

Fig. l is a side elevational view of one form of conventional domestic mixer having my improved agitator associated therewith;

Fig. 2 is a fragmentary enlarged vertical cross sectional view through one form of agitator made in accordance with my invention and taken in the plane of extent of one of the loops thereof;

Fig. 3 is a fragmentary bottom plan view of the form of agitator shown in Fig. 2;

Fig. 4 is a view similar to Fig. 2 with the exception that only the upper portion of the loops appear therein and a modified form. is illustrated therein; and

Fig. 5 is a view similar to Fig. 4 showing a still further modification.

Fig. 1 of the drawing shows an outline view of a form of motor driven domestic mixer which is in common use and which embodies a base ID for supporting a mixing bowl II and an upstanding bracket l2, the latter carrying a casing l3 which is usually movably associated with the bracket l2 and contains an electric driving motor and suitable transmission means. An agitator is designated generally at in Fig. 1 and, as has been hereinbefore indicated, a pair of cooperating agitators are frequently employed.

Each agitator i5 comprises a vertically extending shaft l6 which has at its upper end means for engaging in a hub I! in such manner as to be readily releasable and also so that rotary driving movement of the transmission means in the casing is transmitted to the agitator shaft l6. Such attachment and drivemeans are conventionally found in agitators of this class and have therefore not been illustrated in detail.

At the lower end of the agitator shaft, referring to Figs. 1, 2 and 3 of the drawing wherein one form of my invention is illustrated, there are two loop-shaped members i9 and 20, preferably so formed that they comprise endless strips or bands and also preferably formed from a somewhat resilient material. The loops l9 and 20 are arranged so that their general planes of extent are vertical and at right angles one to the other.

In the form of invention of Figs. 2 and 3, the relative disposition of the loops l9 and 26 is accomplished by providing upper and lower central offset portions on both loops for interfitting with each other. In the loop l9 such upper and lower offset portions, designated 2| and 22 respectively, are oifset inwardly or toward each other and preferably the offset is about one-half of the thickness of the metal of which the loops are formed. In the case of the loop 20, the upper and lower offset portions are directed outwardly or away from each other as at 24 and 25 respectively and these offsets are also preferably about one-half the thickness of the material. It will be seen that the combined offsetting 2| and 2t at the top of the loops l9 and 20, and also the combined offsetting 22 and 25 at the bottom, is equal to one thickness of metal and that therefore the loop portions lying on both sides of the offset portions lie in a common orbit of revolution in the case of both of the loops l9 and 2i].

From the foregoing it will appear that the two loops may, by resiliently compressing the loop i9 in the direction of its length or by resiliently extending the loop 20, or as will be more usual, by a combination of both these actions, be snapped into the interfitting 'position shown in Figs. 2 and 3. While such interfltting may normally be suflicient to retain the parts in assembled relation, in the case of the construction shown in Figs. 2 and 3, assembled relation of the parts is, in the preferred form of my invention, assured by cooperation of the agitator shaft iii.

The agitator shaft 96 of Figs. 1, 2 and 3 has a reduced portion 26 and a squared terminal portion 21. The outer loop 20 is provided at its up per side with a rigidly attached hub 28. Such hub may be secured to the loop 20- by passing a reduced terminal portion 29 of the hub through an opening in the loop 20 and riveting the reduced portion 29 at the side opposite the hub 28. It will usually be advantageous to provide portions on the loops l9 and 20 which are enlarged in the direction of their width at the points of their upper and lower offsetting to provide for the formation of the necessary central openings and to leave the loops sufliciently strong at this point after the openings are formed.

The shaft I6 is grooved to receive and retain a resiliently compressible split ring 32 which may be compressed to the diameter of the shaft l6 for insertion into the central opening in the hub 28. When the enlargement 33 of the hub opening is reached by the spring ring 32 in its movement to assembled relation of the shaft l6 and the hub 28, the spring ring 32 expands and serves as a detent for retaining the shaft I6 and the hub 28 together with the loops l9 and 20 against relative axial movement.

The squared lower terminal portion 21 of the shaft l6 fits into a similarly formed opening in the lower offset portions 22 and 25 of the loops is and 20 respectively to establish positive driving engagement between the shaft l6 and the assembled loops l9 and 20. While I prefer to pass the terminal portion of the shaft is through both lower offset portions 22 and 25 of the loops I9 and 20 respectively, the squared portion 21 may be somewhat shorter than appears in Fig. 2 and pass through the offset portion 22 of the loop l9 only, the lower offset 25 of the loop 20 being in such casev imperforate and the loop 20 being driven through its interfltting engagement with the loop l9.

It will be clear from the foregoing that the agitator assembly of Figs. 1, 2 and 3 may be readily dismantled by first withdrawing the shaft Hi from the hub 28' against the resistance offered by the spring ring 32 and then springing the inner loop l9 out of interfitting engagement with the outer loop 20 or vice 'versa. If desired, the loop 20 only may be used by inserting the shaft I6 in the hub 28 without reassembling the loops l9 and 20.

In the form of my invention which is illus trated in Fig. 4, the agitator shaft 40 engages only the upper intersecting portions of loops El and 42 which are otherwise similar to loops l9 and 20 respectively, excepting their lower portions, while ofiset as in Fig. 2, are imperforate. The shaft Ml has a squared portion 33 which engages a square opening in the inwardlyoifset portion M of the loop ii to drive the loop M in a rotary direction, the loop 52 being driven by reason of its interiitting relation with respect to the loop 4i.

The shaft 40- has a spring ring t5 which engages an enlargement 66 in the axial opening of a hub 51 for resiliently assembling the shaft 39 and the hub 47 against relative axial movement, all as in the previously described form, and the hub M is rigidly associated with the loop 22, also in the same manner as in the'previously described embodiment and the operation of the device in this respect is the same as there shown. The manner of assembly and disassembly is also the same as in the form of Figs. 2 and 8.

In Fig. 5 there is shown a still further embodiment of the invention wherein screw-threaded means are resorted to for detachably associating an agitator shaft 50 and inner and outer agitator loops 5| and 52 respectively. In this embodiment the upper ofi'set portion of the loop 52 is provided with a circular opening and the upper inwardly offset portion of the loop 5| is provided with internal screw threads. To increase the length of the internally threaded portion of the loop 5|, the loop may be provided with an annular flange 53 formed therefrom,

The shaft 50 has a reduced portion 55 which provides a shoulder 55 for abutting the top surface of the loop 52, and the reduced portion 54 extends through the opening in the loop 52 and the reduced portion 54 is screw-threaded for engaging the internal threads of the loop 5|. As in the case of the embodiment of Fig. 4, the lower offset portions of the loops 5| and 52 are ofiset, as in Figs. 2 and 3, but imperforate, and the shaft 50 does not extend between the upper and lower portions of the loops as it does in the modification illustrated in Figs. 2 and 3. The direction of the thread of the threaded portion 55 is such that the rotation of the assembled agitator tends to tighten rather than loosen the threaded engagement.

In the modification of Fig. 5, disassembly is effected by unscrewing the shaft from the loop 5| and separating the loops 5| and 52 in the manner described in connection with Figs. 2 and 3. Obviously, when it is desired to use only one loop in the modification of Figs. 2 and 4, the hub-carrying outer loops and 42 respectively will be employed. In the case of the modification of Fig. 5, however, the inner screw-threaded loop 5| will be employed when only one loop is required, the threads of the reduced portion 54 entering farther into the threaded opening of the loop Si in this event than if both loops were in assembled position.

I claim:

1. For use in a domestic mixing device having motive means for operation thereof, an agitator comprising a shaft having means at one end for ready connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite end comprising a pair of endless loops, one loop having diametrically opposite offset portions and the other of said loops interfitting with said 'offset portions to dispose said loops in such relative position that they substantially intersect at diametrically opposite points, one of said loops being of resilient material whereby the loops may be flexed into and out of interfitting engagement, a. hub associated with one of said loops at one of its points of intersection with said other loop, said shaft extending through said hub and having means for releasably preventing relative axial movement between said hub and said shaft, the outer end of said shaft having means for engagement with one of said loops at the opposite point of intersection for providing rotary driving engagement between said shaft and said loop.

2. In a domestic mixing device having motive means for operation thereof an agitator comprising a shaft having means at one end for connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite end comprising a pair of endless loops adapted in assembled position to intersect at diametrically opposite points, said loops having interfitting portions at such points of intersection, each of said interfltting portions comprising an offset portion on one loop and a recess formed in the other loop for receiving said offset portion, one of said loops being ofresilient material whereby the loops may readily be flexed into and out of interfltting engagement to disassemble said loops for cleaning and the like, and means on one of said loops for driving engagement with said shaft.

3. In a domestic mixing device having motive means for operation thereof, an agitator comprising a shaft having means at one end for ready connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite end comprising a pair of endless loops, each loop having diametrically opposite portions in substantial abutment with 1' corresponding portions of the other loop to dispose said loops so that they substantially intersect at diametrically opposite points with one loop extending across the outside of the other at diametrically opposite points, a hub on the outer loop at one of the points of abutment of said loops for detachable engagement with said shaft at a point spaced from the end of the shaft, said shaft having a non-circular terminal portion for entering correspondingly formed openings in both loops at their point of abutment which is opposite to said hub to establish rotary driving engagement between said shaft and said loops and for preventing relative rotary movement between said loops about the axis of said shaft.

4. In a domestic mixing device having motive means for operation thereof, an agitator comprising a shaft having means at one end for ready connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite and comprising a pair of endless loops, each loop having diametrically opposite portions in substantial abutment with corresponding portions of the other loop to dispose said loops so that they substantially intersect at diametrically opposite points with one loop extending across the outside of the other at diametrically opposite points, a hub on the outer loop at one of the points of abutment of said loops for detachable engagement with said shaft at a point spaced from the end of the shaft, the terminal portion of said shaft engaging openings formed in both loops at their point of abutment which is opposite to said hub to reinforce said loops and retain their axes in alignment with said shaft.

5. For use in a domestic mixing device having motive means for operation thereof, an agitator comprising a shaft having means at one end for ready connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite end comprising a pair of endless loops, one of said loops fitting within the other to dispose said loops in such relative positions that they substantially intersect at diametrically opposite-points, detent means acting between said loops whereby said loops are resiliently but removably retained in preliminary assembled position, aligned openings in said loops at one of their points of intersection for the reception of the shaft whereby the shaft serves to key the loops to each other against resilient disassembly when the loops are disposed upon the shaft, and means for releasably retaining said assembled loops upon said shaft.

6. Fbr use in a domestic mixing device having motive means for operation thereof, an agitator comprising a shaft having means at one end for connection with said motive means for rotation of said agitator, said shaft having agitating means associated with its opposite end comprising a pair of readily separable endless loops, one of said loops fitting within the other to dispose said loops in such relative positions that they substantially intersect at diametrically opposite points when assembled, and detent means acting between said loops at their points of intersection whereby said loops are resiliently but removably retained in assembled position, one of said loops being attached to said agitator shaft.

ROBERT C. WOLFE.

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