US2607491A - Flour sifter - Google Patents

Description

I 1952 E DENNIS 0 FLOUR SIFTER Filed Jan. 26, 1948 E ucfim Den/7 7'5 Patented Aug. l9, 1952 FLOUR SIFTER E LucianDennis, Rockford, 111., assignor to The Washburn Company, Worcester, Mass, a corporation of Massachusetts Application January 26, 1948, Serial No. 4,253

' f 6 Claims. (01. 209-357) This invention relates to improvements in flour sifter.

It has been a problem in the manufacture of flour sifters, where the agitators are arranged to be oscillated by means of an oscillatable handle linked by a connecting rod to the crank that oscillates the agitators, to avoid havingthe crank reach a dead-center position or too close to such a position. thereby interfering with easy operation of the oscillating handle, this problem being aggravated because of the loose fit and consequent play between the parts, and also because of the inability generally to work to any closer limits in the quantity production of such utensils, and also because of the fact that the agitators are turned quite rapidly back and forth and are accordingly apt to be thrown to or past a deadcenter position if the play is sumcient to permit.

It is, therefore, the principal object of my invention to provide an improved form of crank element having on the outer end of the arm thereof a pair of stops spaced for positive engagement with the connecting rod in the two limit positions of the crank arm for positively limiting the swing of the crank soas to avoid the. objections mentioned. I

Another object is to provide a crank element made from a single strip of sheet metal formed to provide: 7

(l) A shaft for turning the, agitators;

(2) A crank arm formed by a right angle bent end portion of the strip;

.(3) A pair of stop shoulders formed by bending the outer end of the crank arm to U-shaped form, and

(4) An easily twistable T-s-haped end portion on the end of the shaft portion remote from the crank arm, which, when twisted into a plane at right angles to the plane of the rest of the shaft portion, serves to prevent endwise displacement of the shaft from assembled relationship to the agitators.

Theinvention is illustrated in the accompanying drawing, in which- Fig. l is a central vertical section through a flour sitter, embodying the aforesaid improvements of my invention;

Fig. 2 is a bottom view of the sifter, indicating in dotted lines the opposite extreme position of the crank arm from that appearing in full lines;

Fig. 3 is a perspective viewof the one-piece, sheet metal crank element prior to its assembly in asifter;

Fig-f is a plan viewv of. the hub portion of the uppermost agitator, showing how the twisted end Fig. 5 is a sectional detail on the line 5.5. of

Fig. 4.

The samereference numerals areapplied to corresponding parts throughout the views.

Referring to Figs. land 2, the sifter comprises a sheet metal body or container 6 of tubular form, open at the top and bottom, and having a series of screens I mounted therein in spaced parallel relation. Each screen is part of a separate sieve unit,. of which there are three in the present sifter, the screens being assembled in sheet metal rings 8. made to fit closely inside the container, each screen beingc'linched at its outer edges by the inwardly curled lower edge Set the ring. -A diametrically extending brace strip 10f sheet metal, which is preferably ribbed longitudinally as at ll for stiffening and, to resist bending, s provided under the screen 1 of each sieve for sup: port thereof, the strip being in turn supportedat its ends on top of the curled edge 9 ofthe ring, as shown, andbeing furthermore pierced atits mid-point and secured to the center of the screen associated therewith by means of a circularv grommet oreyelet, 12, whereby to hold the brace per manently in the position described, Two diametrically opposed sheet, metal clips l3 that, are preferably; riveted to the wall ofthe container, as at I4, serve to hold the three sieves in place in the container, with the top sieve disposed in abutment with the annular shoulder l5 defined in the bore of the container by a bead formed in the wall in the manner shown. A hexagonal-agitator l6 cooperates with each screen i, and the group of agitators is oscillated by meanspof the, shaft portion I? of the crank element.,showninFig fi and designated generally by the referencejnue meral l8.- This crank element has a crank arm It pivotally. connected at its specially, shaped outer end portion 20 with the front end portion of a wire or rod link 2|, which in turn is pivotally connected at its rear end with the lower endpf a stamped sheet metal'trigger or lever 22 for oscillation of all of the agitators VI 8 in unison upon oscillation of said trigger. The trigger is operated by the fingers of the operators hand that graspsthe handle 23, the trigger being disposed in forwardly spaced relation tothe-handle-for that purpose, as clearly appears inyFig; 1; ;:In that figure it will be noticed that the 'handle;23,- which may beof wood or composition or plastic material, is riveted at'its" upper endfas at 24,1 in the rear end of a sheet metal channel" member 2 5, that is suitably secured atits' front end to the wall of the container 6, the lower end of the handle being riveted, as at 26, in the rear end of a U-shaped sheet metal yoke 21, in front of the cross portion of the U, and the front ends of the arms of the U being suitably secured to the wall of the container. The trigger 22 is pivoted relative to the handle structure at its upper end on a cross-pin 28 that supported at its opposite ends in the opposed side walls 29 of the channel 25. A bowed leaf spring 30 has one end set in a recess 3| provided in the front of the handle 23 and bears at its other end against the shoulder 32 formed on the back of the trigger 22 near its upper end. The spring is held against lateral displacement from the handle structure by having its arched middle portion disposed between the side walls 29 of channel 25, as shown. The link 2| extends freely through a hole 33 in the wall of container 6 and has its rear end portion bent downwardly to provide the pivot pin portion 34 'for'pivotal connection with the lower U-shaped end portion 35 of the trigger 22. A hole 36 is provided in the substantially vertical cross-portion of the U through which the wire link 2| extends freely, and thereis another hole 31 in the lower substantially horizontal arm of the U through which the bent pivotal end portion 34 of the wire link projects. The lower end 35 of the trigger is threaded onto the. end 34 of the link 2| before the trigger is assembled in the handle structure. Thereafter the parts described cannot become disassembled, no matter how vigorously the sifter is operated.

In operation, when the trigger'22 is pressed or squeezed and is thereby moved toward the handle 23 against resistance of spring 30, the link 2| moving with it slides freely in the hole 33 and moves crank arm l9 and the set of agitators |6 with it through an angle of approximately 100 or more, as indicated by the dotted moved position of the crank arm l9 in Fig. 2. When the trigger 22 has been moved as far as it will go, or nearly so, finger pressure thereon is released and thespring 30 returns the trigger and the aforesaid parts thereto attached to their starting positions. The operation is smooth and quiet and consumes very little energy so that the operator is not fatigued. The improved construction of the crank element |8 improves the operation by eliminating any possibility of the crank arm l9 reaching a dead-center position relative to-link 2|, or so close to such a relationship, which would interfere with smooth and easy operation. This is because of the positive limiting of relative movement of these two parts l9 and 2| angularly with respect-to one another, as shown in their two extreme positions in Fig. 2. The sheet metal strip of oblong rectangular transverse-section, from which the crank element |8 ismadeis formed between dies to offset the outer end portion-20 in parallel relation'to the rest'oflthe crank arm I9 and at the same time define transverse walls 38 and 39' at opposite ends of said ioifs'et portion in planes at right angles to the planes of theinner and offset outer endportions of the crank arm. These walls also lie oblique to each other aswell as oblique to the axis of the 'cra'nk 'arm, have a length as measured horizontally at least equal to the broad side of the crank arm and are arranged in a horizental .V openingtin the general direction of the handle as most clearly appears in Figs. 2 and 3. A'thole40 is'punched'in the offset end portion which can be termed the weblinking the two walls,38, 39, the hole lllzbeing located equidistant between these walls, and the wire link 2| has an upwardly bent end 4| entered freely in this hole to provide the pivotal connection between the link 2| and crank arm IS. The upwardly bent end 4| is bent again at right angles to provide an arm 42, which, with the pivot 4|, defines a hook on the end of the link 2| that will not become disconnected from the crank arm |9 when once properly connected therewith, the arm 42 serving also by abutment with walls 38 and 39 to define the opposite limits of movement of the parts l9 and 2|. In the assembling of the sifter at the factory the arm 42 can easily be bent to the right or left relative to the rest of the link 2| if a test shows that the arm l9 and link 2| otherwise come too close to a dead center relationship at the one or the other limit position. Such an adjustment can be made with a pair of pliers and when once made at the factory will never be apt to require any further attention,'because the trigger 22 is not operated with suificient force to give rise to danger of the arm 42 getting bent out of the angle set at the factory.

In conclusion, it will be noticed that the shaft portion llof the crank element I8 is reduced in width slightly in relation to the crank arm end whereby to define shoulders 43 for abutment with the eyelet l2 on the lowermost screen to prevent upward displacement of the crank element l8 from assembled position. The shaft portion of the crank element fits nonrotatably in the diametrical slots 44 molded in the hubs 45 of the agitators [6, which, as stated before, are molded in one piece of plastic material to the final form desired, so that no machining is needed The upper end of the shaft portion I1 is notched out on both sides, as at 46, to form an easily twistable T portion 41 for securing the crank element l8 in assembled relationship to the uppermost agitator and preventing downward displacement thereof from assembled position, as shown in Figs. 1, 4 and 5. This novel one-piece construction of the crank element means quite a reduction in the number of parts needed for the sifter and, besides making for lowered cost of production, makes for closer uniformity in quantity production, and a truly higher quality device in the final analysis. The one-piece plastic construction of the agitators is of advantage in eliminating any danger of these parts rusting after they have been in service for a time. This construction also enables specially shaping the hub portion to obtain improved performance. For example, it will be seen in Fig. 1 how the increased axial length of the hubs insures keeping .:the two lower agitators in the desired spaced relation to the screens above so that they remain in the desired close working relationship to the screens therebeneath for eficient sifting, the uppermost agitator being, of course, held down on its screen by the twisted end 41 of the shaft portion Next, notice in Fig. 5 the downwardly projecting annular bead 48'formed on the bottom of the hub portion 45 of each agitator arranged to ride on top of the screen therebeneath around the eyelet I2 and support the agitator at a predetermined small elevation relative to the screen for most efilcient sifting. Also, note the recess 49 in the bottom ofzthe hub for reception of the eyelet |2 with ample operating clearance. The bead 48 and recess 49 together insure proper relationship of each agitator to the screen associated therewith. It is believed the foregoing description conveys a good understanding of the objects and advantages of my invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

I claim:

1. As an article of manufacture, a combination agitator drive shaft and operating crank member for a flour sifter and the like, comprising a one-piece elongated sheet metal body of oblong substantially rectangular transverse section bent to define a vertical shaft portion adapted to fit non-rotatively in a similarly shaped opening in the agitator, and a crank arm portion extending transversely with the broad side thereof in a horizontal plane, the outer end portion of said crank arm being bent obliquely to the axis of the crank arm to establish a pair of walls formed by the broad side of said crank arm and which walls are arranged substantially as a horizontal V with a web portion ,therebetween, said web portion being provided with an aperture equidistant between said walls to provide a pivotal connection between said crank arm and the end portion of an actuating link therefor, the said end portion of the link being oscillatable between said walls at the wide open end of the .V.

2. An article of manufacture as set forth in claim 1, wherein the shaft portion of the body is of reduced width in relation to the rest of the body throughout the major portion of its length so as to define, near the crank arm, opposed shoulders for location of the shaft portion endwise with respect to a sifter element in the assembling of the part in a sifter.

3. An article of manufacture as set forth in claim 1, wherein the shaft portion of the body is of reduced width in relation to the rest of the body throughout the major portion of its length so as to define, near the crank arm, opposed shoulders for location of the shaft portion endwise with respect to a sifter element in the assembling of the part in a sifter, the shaft portion being notched on opposite sides near the free end thereof to provide a short portion of reduced width that may be easily twisted so as to permit disposition of the extremity of said shaft portion in transverse relation to the rest of the shaft portion to locate the shaft portion endwise in relation to an agitator part of a sifter.

4. In a manually operable flour sifter, comprising a container having an open top and bottom and equipped with a handle on the side, a sifting screen extending transversely in said container over which an agitator is disposed and adapted to be turned, and a trigger oscillatable relative to the handle and reciprocating a pushpull link adapted to oscillate a crank to oscillate the agitator, the improvement which consists in a combination agitator drive shaft and operating crank member comprising a one-piece elongated sheet metal body of oblong substantially rectangular transverse section bent to define a vertical shaft portion and on the lower end thereof a crank arm portion extending transversely with the broad side thereof in a horizontal plane, said shaft portion being adapted to fit non-rotatively in a similarly shaped opening in the agitator, the outer end portion of said crank arm being bent obliquely tothe aXis of the crank arm to establish a pair of walls formed by the broad side of said crank arm and which Walls are arranged substantially as a horizontal Vv with a web portion therebetween, said web portion being provided with an aperture equidistant between said walls for receiving and establishing a pivotal connection for the corresponding end portion of said aforesaid push-pull link and. which end portion is oscillatable between said broad-sided walls which serve as stops therefor.

5. A flour sifter as set forth in claim 4, wherein the shaft portion of said combination drive shaft and crank member is of reduced width in relation to the rest of the member throughout the major portion of its length so as to define, near the crank arm, opposed shoulders for location of the shaft portion endwise with respect to a sifter screen in the assembling of the part in the sifter.

6. A flour sifter as set forth in claim 4, wherein the shaft portion of said combination drive shaft and crank member is of reduced width in relation to the rest of the member throughout the major portion of its length so as to define, near the crank arm, opposed shoulders for location of the shaft portion endwise with respect to a sifter screen in the assembling of the part in the sifter, the shaft portion being notched on opposite sides near the free end thereof to provide a short portion of reduced Width that may be easily twisted so as to permit disposition of the extremity of said shaft portion in transverse relation to the rest of the shaft portion to locate the shaft portion against endwise displacement in a downward direction in relation to the agitator.

E LUCIAN DENNIS.

REFERENCES CITED UNITED STATES PATENTS in the Number Name Date 408,780 Wilsey Aug. 13, 1889 464,416 Benson Dec. 1, 1891 619,166 Gragert Feb. 7, 1899 1,002,343 Wantling Sept. 5, 1911 1,070,824 Lehrmann Aug. 19, 1913 1,488,306 Adams Mar. 25, 1924 1,802,923 Melish Apr. 28, 1931 2,015,087 Rafton Sept. 24, 1935 2,153,879 Andrews et al Apr. 11. 19 9 2,181,718 Arnold Nov. 28, 1939 2,204,920 Bailey June 18, 1940- 2,244,186 Braun June 3, 1941 2,314,186 Zuck Mar. 16, 1943 FOREIGN PATENTS Number Country Date 430,048 Great Britain June 12, 1935

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