US3415376A - Flour sifter - Google Patents

Description

1968 M. J. SMITH ETAL 3,

FLOUR SIFTER Filed Jan. 20, 1967 DOD .DCI IIID DUDOG INVENTORS. MAHLON J. SMITIH RICHARD Ev HENDERSON United States Patent 3,415,376 FLOUR SIFTER Mahlon J. Smith, Niles, Mich., and Richard E. Henderson, Oregon, 111., assignors to The Washburn Company, Worcester, Mass., a corporation of Massachusetts Filed Jan. 20, 1967, Ser. No. 610,689 9 Claims. (Cl. 209--236) ABSTRACT OF THE DISCLOSURE This flour sifter is of a small size designed to fit in ones hand and be operated by opening and closing the hand. It is of plastic construction throughout, making it possible to wash it thoroughly at intervals without danger of any part thereof rusting. There is no separate spring, spring action being obtained by flexing a resilient lever fixed on one side of the sifter at one end and pivotally connected at the other end to an agitator operating link. The lever and link, also the lever attaching part, are all molded in one piece of polypropylene or the like with an integral web hinge connection between the lever and driver link for the one pivot, and a similar integral thin web hinge connection between the other end of the lever and the part attached to the sifter body.

This invention relates to a sifter for flour or like materials and, more particularly, to a small sifter of approximately single cup or cup and one-half capacity, better suited for a large variety of cookie and pastry baking operations than the conventional larger capacity sifters.

A general object of the invention is to provide a sifter of the foregoing kind which, as contrasted with prior art sitters, as, for example, Dennis Patent 2,695,708, is constructed at lower cost with fewer and simpler parts, and adapted to give better and smoother performance and have greater durability.

A more specific object of the invention is to simplify the construction of a sitter by providing a unique design including a flexible lever which is arranged to be flexed in the operation of the sifter and eliminates the need for a separate spring required in prior art sifters to return the agitator after each forward movement.

Another object of the invention is to simplify the construction and assembly of a sifter by the formation in one piece of a combined spring action lever and agitator operating link, there being integral flexible hinges provided at opposite ends of said lever, one for connecting the upper end of the lever to an upper attaching member fastened rigidly to the sifter body, while the other serves to connect the lower end of the lever to the outer end of the link.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawing, in which:

FIG. 1 is a perspective view of a sifter made in accordance with the invention and illustrating how the same is adapted to be grasped and operated between the thumb and two or more fingers of one hand;

FIG. 2 is an enlarged central vertical section through the sifter of FIG. 1;

FIG. 3 is a horizontal section taken along the line 3-3 of FIG. 2, showing the parts on a smaller scale;

FIG. 4 is a section similar to FIG. 3 and on the same scale showing the agitator rotated to the other extreme position from that of FIG. 3;

FIG. 5 is a plan view substantially full-size of a onepiece molded plastic element adapted to form an operating spring lever and driver link for the sifter of FIG. 1;

FIG. 6 is a side elevation of the one-piece molded plas tic assembly of FIG. 5;

FIG. 7 is a plan view substantially full size of a screen for the sifter, and

FIG. 8 is a perspective view of a spider agitator shown substantially full size.

The same reference numerals are applied to corresponding parts throughout these views.

As shown in the drawing, for purposes of illustration, the invention is embodied in a sitter having an elongated sifter body 10 of hourglass cup shape partly to facilitate holding the same in one hand and also for the sake of good appearance, the same having a longitudinally extending bore of circular cross section extending from an open upper end 11 at the top of the body to a lower open end 12 at the bottom of the body. The material to be sifted, which is usually flour, is scooped into the body through the top opening and comes to rest on a screen 14 in the lower end portion of the body. The flour is agitated relative to the screen to gravitate and sift through the openings therein upon oscillatory movement of an agitator 15. Herein, the agitator is a rotatable spider lying on the screen and mounted for oscillation about an axis through a pivot pin 16 (FIG. 2) rotatable in the center of the screen. An elongated flexible resilient lever 20 is attached in a novel manner at its upper end on the outer side of the body 10 and, at its lower end, is drivingly connected in a novel manner to the spider 15 through a driver link 18 to oscillate the spider as the lower end of the lever in the flexing thereof swings toward and away from the body 10.

In accordance with the present invention, the lever 20, its attaching member 21 on one end of said lever, and the driver link 18 on the other end are molded in one piece of polypropylene or the like with an integral thin web hinge connection 22 between the lever and driver link so that the lever is flexible laterally to provide the necessary pivotal or hinge action for oscillation of the lower end of the lever relative to the driver link as well as the spring action in the flexing of the lever relative to its similar but longer and thicker integral web hinge connection 23 with the attaching member 21 for returning the driver link to a normal outermost position of rest shown in FIG. 2. The elongated attaching and supporting member 21 extends downwardly along and is secured to the outside of the sifter body adjacent its top rim. To permit that member 21 as well as the driver link 18 to be molded as one flat piece, which is bent later into its final configuration, the additional hinge connection of web form seen at 23 joins the upper end of the lever 20 to the upper end of the attaching member 21. Opposed flat abutments 24 and 25 extend substantially radially relative to the hinge axis defined at 23 and are formed on adjacent facing sides of the attaching member 21 and upper end portion of the lever 20, respectively, to engage each other and form a rigid support for the upper end of the lever when the lever is flexed in the operation of the sifter. Similar opposed flat abutments 26 and 27 are formed on adjacent faces of the lower end of the lever 20 and the adjacent end of the link 18, respectively, to limit return movement of the link under spring action of the lever.

The member 21 is of shallow channel form providing outwardly projecting strengthening ribs 28 extending along the longitudinal edges of the member 21 to the abutments 24, which extend farther outwardly from the plane of the member adjacent the hinge connection 23 with the lever 20. A pair of circular openings 29 in the member 21 are spaced longitudinally of its center line to receive studs or pins 30 and 31 molded integral with sifter body for securing the member 21 to the side wall of the sifter body 10. The upper pin 30 is longer than the lower pin 31 and after entry in the hole 29 has its protruding end swedged over under heat and pressure to provide a reliable permanent connection of an economical type. The lower pin has a smaller head preformed on its outer end and this pin has .a snap-fit in its hole 29 to complete that fastening.

When the blank for the lever and link assembly of FIGS. 5 and 6 is removed from a molding die and is still hot, the member 21 is moved bodily relative to the lever several times between its flat position of alinement with the lever and another position in which the abutments 24 and contact one another. This results in flexing of a narrow section of the upper hinge 23, and the molecules of the polypropylene therein are rearranged so that that section may be flexed innumerable times as a hinge without breaking, in spite of the thinness of the section. Also, while the blank is still hot, the other and thinner web at the lower hinge 22 is flexed and bent to rearrange the molecules of this section in a similar manner for the same purpose.

The lever 20 is of channel form with strengthening ribs 32 formed integral with its longitudinal edges. At one end, the ribs 32 terminate in the abutments 25, and at the other end they terminate in the abutments 26. The arched thicker web 23 permits disposition of the lever 20 at a small angle relative to member 21, as seen in FIG. 2, while the thinner web 22 permits disposition of lever 20 at right angles to link 28 and to pivot relative thereto to a greater angle as required in the operation of the sifter, without any danger of fatigue and finally breakage.

The driver link 18 includes a straight portion 37 extending from the lower hinge 22 and through a slot 33 provided in the lower wall of the sifter body 10. On the free end of the driver link 18 is an arcuate crank 34 for connection with the agitator 15, a circular upwardly tapered aperture 35 being formed in the extremity of the crank to receive with a snap-in fit a headed pin 36 integral with one spoke 46 of the spider 15 near its outer end, this snap connection being similar to that of pin 31 in the tapered hole in attaching member 21. The straight portion 37 of the driver link is disposed on a radial line toward the longitudinal axis of the agitator 15 while the pin 36 and crank end are spaced radially outward of this axis. The crank and pin convert the reciprocation of the driver link 18 into the oscillatory movement of the spider 15.

In operation, the slant of the top of the sifter body is of advantage in scooping flour out of a canister or bag, and this is particularly true when it is necessary to scoop the remaining flour out of a corner of a container. To operate the sifter, the lever 20 is grasped by two or more fingers of one hand while the thumb engages the far side of the sifter body 10, as seen in FIG. 1, or alternatively, the lever 20 is grasped by the thumb with the fingers extended around the sifter body. As the hand is then closed, the lower end of the lever 20 is flexed relative to its upper end at the abutments 24 and 25 adjacent the upper hinge 23, moving the driver link 18 linearly inwardly in a generally horizontal plane (FIG. 2) to oscillate the agitator 15, the driver link being guided in this movement by the slot 33. during this inward movement of the driver link, the slanted surfaces 26 and 27 adjacent the lower hinge 28 separate. Upon opening the hand, the lever 20 straightens and its lower end moves away from the sifter body 10 pulling the driver link 18 outwardly through the slot 33 until the lever 20 returns to its outer limit position determined by abutment of the crank portion 34 with the inner wall of the sifter body adjacent the slot 33, as shown in FIG. 3. During a sifting operation, the operator performs a series of such closing and opening motions of the hand, causing rapid reciprocations of the driver link and accompanying oscillations of the agitator 15 relative to screen 14. Grasping and controlling the sifter body 10 using only one hand is facilitated by forming the body with an hourglass shape in which the central diameter is less than the diameters of the upper and lower end portions. This novel shape obviously also improves the general appearance of the sifter.

To provide a low-cost construction and a construction which will not be subject to getting rusty because of frequent washings, it is preferred that the entire sifter assembly, including the screen 14, usually made of wire screen, be formed of molded plastic material. To retain the sifting screen 14 in place, a downwardly facing ledge 38 is formed around the inner wall of the sifter body adjacent the lower opening 12. The ledge forms the upper side of an annular groove 39 defined in the interior body wall between the upper shoulder 38 and a lower lip or flange 40. The latter is of a relatively thin cross-section for flexibility and projects from the wall of the body downwardly and inwardly toward its axis, thus providing a flexible retaining lip for the screen 14 below groove 39, so that the screen 14 may be shoved upwardly past the lip 40 when the latter is flexed to a larger diameter than the screen 14 to admit the screen. When the periphery of the screen 14 is fitted in the groove 39, the lip 40 retains the screen. To make this method of assembly feasible we provide a gap 41 at one point in the circumference of the lip 40, enabling the same to flex outwardly more readily than it would if the lip were continuous. The downward flare of the lower portion 12 of the sifter body 10 combined with the upward taper on the periphery of the screen 14 also makes for easier assembly.

The screen 14 is a molded plastic circular flat disc with a grid of uniformly spaced square openings 42 formed therein in molding the part of plastic material. To assure that the flour moves freely through the openings and does not clog in the latter, the openigns 42 taper upwardly, that is, they are larger at the bottom surface 43 of the screen than at the top surface (see FIG. 2). The taper of the square openings 42 facilitate the release of the plastic screen 14 from its die in the molding operation. The screen 14 is also formed with an upwardly tapered central bearing opening 44 for a downward press fit of the center pin 16 on the agitator, this connection being similar to that at pins 31 and 36.

The agitator spider 16 is also preferably molded from the same plastic material as the other parts, with a central hub 45 and six radial arms 46 projecting outwardly from the hub at 60 intervals. The pivot pin 16 is integral and coaxial with the hub and extends downwardly therefrom through the central bearing opening 44 in the screen 14. The agitator 15 rests on the top surface of the screen 14 and slides across the latter during oscillation of the agitator by the driver link 18.

The sifter illustrated herein is of the small cup or one and a half cup size, either of which sizes is convenient for sifting flour in making cookies, pastries, gravy or the like. This sifter can be readily stored in a canister or bag of flour and its all plastic construction permits the same to be readily Washed without any danger of rusting due to any residual moisture. Moreover, the sifter is of economical construction suitable for mass production.

It is believed the foregoing description conveys a good understanding of the objects and advantages of our invention. The appended claims have been drawn to cover all legitimate modifications and adaptations.

We claim:

1. In a sifter for flour or like materials comprising a sifter body having a top opening into which material to be sifted is supplied, said body having a lower opening covered by a screen which holds said material within the sifter body while permitting some of the material to gravitate and sift through openings in the screen when agitated, and an agitator lying on top of and movable across said screen to agitate said material relative to said openings, the improvement comprising an elongated manually flexible resilient lever which is fixedly mounted at one end on the outside of an upper portion of said body and extends downwardly and is connected at its lower end with means operatively connecting said lever with said agitator, the latter being thereby moved in one direction relative to the screen as said lever is flexed manually toward said sifted body and being moved in the opposite direction under spring action of said lever when the latter moves away from said sifter body as manual flexing pressure thereon is relieved, said lever being of molded plastic material and the fixed mounting for said lever on said sifter body comprising a plastic attaching member integrally hingedly attached by a flexible plastic web to the upper end of said lever and rigidly secured to the sifter body, said attaching member having the upper end ofsaid lever fulcrumed thereon.

2. In a sifter for flour or like materials comprising a sifter body having a top opening into which material to be sifted is supplied, said body having a lower opening covered by a screen which holds said material within the sifter body while permitting some of the material to gravitate and sift through openings in the screen when agitated, and an agitator lying on top of and movable across said screen to agitate said material relative to said openings, the improvement comprising an elongated manually flexible resilient lever which is fixedly mounted at one end on the outside of an upper portion of said body and extends downwardly and is connected at its lower end with means operatively connecting said lever with said agitator, the latter being thereby moved in one direction relative to the screen as said lever is flexed manually toward said sifter body and being moved in the opposite direction under spring action of said lever when the latter moves away from said sifter body as manual flexing pressure thereon is relieved, said lever .being of molded plastic material and the means operatively connecting the lower end of said lever with said agitator comprising an elongated plastic link one end of which is connected with said agitator, the other end being integrally hingedly attached by a flexible plastic web to the lower end of said lever.

3. In a sifter for flour or like materials comprising a sifter body having a top opening into which material to be sifted is supplied, said body having a lower opening covered by a screen which holds said material within the sifter body while permitting some of the material to gravitate and sift through openings in the screen when agitated, and an agitator lying on top of and movable across said screen to agitate said material relative to said openings, the improvement comprising an elongated manually flexible resilient lever which is fixedly mounted at one end on the outside of an upper portion of said body and extends downwardly and is connected at its lower end with means operatively connecting said lever with said agitator, the latter being thereby moved in one direction relative to the screen as said lever is flexed manually toward said sifter body and being moved in the opposite direction under spring action of said lever when the latter moves away from said sifter body as manual flexing pressure thereon is relieved, said lever being of molded plastic material and a plastic attaching member is integral with the upper end of the lever secured to an outer side wall of the sifter body, the means connecting the lower end of said lever to said agitator comprising a plastic link, and flexible plastic web hinges integrally hingedly connecting the lever and link at one end of the lever and the lever and attaching member at the other end of the lever.

4. In a sifter for flour or like materials, comprising a sifter body having a top opening into which material to be sifted is supplied, said body having a lower opening covered by a screen which holds said material within the sifter body while permitting some of the material to gravitate and sift through openings in the screen when agitated, and an agitator lying on top of and movable across said screen to agitate said material relative to said openings, the improvement comprising providing said sifter body of molded plastic material with an annular internal groove provided in the lower end portion to receive said screen, said groove having an annular inwardly projecting shoulder integral with said body defining the one side thereof and a flexible resilient annular inwardly projecting lip integral with said vbody defining the other side thereof, said lip being adapted to be spread radially enough to allow passage of the peripheral portion of said screen in entering the screen. into said groove, said lip being thereafter adapted to contract to substantially its initial radius to retain said screen in said groove, said sifter body and groove being of downwardly flared form internally to facilitate entry and assembly of said screen in said groove and said screen being of rigid construction and having the periphery thereof tapered to conform to the downward flare of said body and groove to further facilitate assembly.

5. The structure as set forth in claim 4 wherein the lip has at least one break in its circumference to enable easier spreading of the same.

6. In a sifter for flour or like materials comprising an elongated sifter body having a bore extending from an upper open end to a lower open end, a screen secured in said body across the lower open end of the bore, and an agitator oscillatably mounted on the screen and operable on the top surface thereof, the improvement comprising an integral, one-piece molded plastic member providing an elongated flexible resilient operating lever, an attaching member rigidly attached to said sifter body and connected integrally to one end of said lever to support the lever exteriorly of the sifter body, and a driver link connected by an integral hinge to the other end of said lever and extending through a slot provided in said sifter body to the interior thereof where the driver link is connected to the agitator, the first mentioned end portion of the lever flexing relative to said sifter body under manual pressure to provide a spring action for reciprocating the driver link and thereby oscillating the agitator.

7. The structure of claim 6 in which the one-piece molded plastic member is made of molded polypropylene having connecting webs of reduced thickness at the junctures between the lever and the attaching member and the driver link, said webs being flexed while still hot to form flexible hinges.

8. As an article of manufacture, a one-piece elongated molded plastic member providing an elongated flexible resilient lever, a relatively short attaching member connected by an integral flexible plastic hinge to one end of said lever, and a link connected by an integral flexible plastic hinge to the other end of said lever, whereby the three-part assembly is in one piece and is adapted to be handled as such.

9. An article of manufacture as set forth in claim 8 in which the one-piece molded plastic member is made of material having substantially the properties of polypropylene, whereby when the integral hinge portions are flexed While the molded material is still hot, said hinges remain flexible thereafter and are durable.

References Cited UNITED STATES PATENTS Wolf 209-357 Cullen et a1. 209-357 Parrella 150-33 Sturrock 209-357 X Collier 209-357 X Dennis 209-357 Schlabach et a1. 264-249 8 Perkins 209-357 Fitzgerald 150-05 Hofer et a1. ISO-0.5 SWett et al 209-283 X FOREIGN PATENTS Canada.

FRANK W. LUTTER, Primary Examiner.

TIM R. MILES, Assistant Examiner.

US. Cl. X.R.

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