US2770439A

US2770439A - Apparatus for filling powdered or granular materials into bags

Info

Publication number: US2770439A
Application number: US456768A
Authority: US
Inventors: Neil S Stafford; George A Worley
Original assignee: FMC Corp
Current assignee: FMC Corp
Priority date: 1954-09-17
Filing date: 1954-09-17
Publication date: 1956-11-13
Anticipated expiration: 1973-11-13

Description

Nov; 13, 1956 N. s. STAFFORD ET AL 2,770,439

APPARATUS FOR FILLING POWDERED 0R GRANULAR MATERIALS INTO BAGS Filed Sept. 17, 1954 4 Sheets-Sheet 1 F rllltlr' O K A 4 O .f B 6 4 3 ZJ m m 25 a n W A i A 2 6 n O 5 9 4 i 3 2 A awww A m s swarm 4 z I s mm .4 123m win-F 02 a a A w .5% O I l 10 I.

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T INVENTORS I E l NEIL s STAFFORD I ozone: A WORLEY av '5,

A ATTORNEY Nov. 13, 1956 N. s. STAFFORD ET AL 2,770,439

APPARATUS FOR FILLING POWDERED OR GRANULAR MATERIALS INTO BAGS Filed Sept. 17, 1954 4 Sheets-Sheet 2 INVENTORS NEIL S. STAFFORD GEORGE A. WORLEY ATTORNEY Nov. 13,- 1956 N. s. STAFFORD ET AL 2,770,439

APPARATUS FOR FILLING POWDERED OR GRANULAR MATERIALS INTO BAGS Filed Sept. 17, 1954 4 Sheets-Sheet 3 INVENTORS ATTORNEY FII3 E| NEIL s. STAFFORD GEORGE A.WORLEY Nov. 13, 1956 N. s. STAFFORD ET AL 2,770,439 APPARATUS FOR FILLING POWDERED 0R GRANULAR MATERIALS INTO BAGS Filed Sept. 17, 1954 4 Sheets-Sheet 4 P'II3 '7 INVENTORS NEIL S. STAFFORD GEORGE A.WORLEY ATTORNEY United States Patent APPARATUS FOR FILLING POWDERED OR GRANULAR MATERIALS INTO BAGS Neil S. Stafford, San Jose, and George A. Worley, Newark,

alif., assignors to Food Machinery and Chemical Corporation, San Jose, Calif., a corporation of Delaware Application September 17, 1954, Serial No. 456,768

6 Claims. (Cl. 249-60) The present invention relates to apparatus for filling powdered or granular materials into bags. More particularly, the present invention relates to apparatus, of the type referred to, which employ aeration of the powdered gr granular material to facilitate delivery thereof into the ags.

Apparatus of this type comprise usually a tank of substantial height wherein the powdered or granular materials are placed into a fluid-condition with currents of air or other gaseous flnidizing media, a discharge spout at the lower end of said tank over which the filling snout of the bag is engaged and through which the fluidized mass of powdered or granular material flows into the bag, control mechanism by means of which the spout may be opened or closed, and a weighing mechanism which supports the bag in material-receiving position and which is arranged to cause the spout control mechanism to block further flow of the material Whenever a predetermined quantity of the material has been filled into the bag.

It is an object of the present invention to provide a discharge spout, for bag filling apparatus, comprising control mechanism that is operable to block rapidly the discharge of fluidized material through said spout.

Another object is to provide a spout control mechanism that is of simple construction yet rapid and dependable in operation.

Another object is to provide a flow control valve for powdered materials that comprises a flexible tube and means for pinching the tube for the purpose of stopping flow of the fluidized material therethrough.

Another object is to provide a flexible tube for a valve, of the type referred to, that may readily be pinched off without placing harmful strains on its walls.

Another object is to provide a simple and etfective supporting structure for the bags while they are being filled.

Another object is to provide a simple and effective supporting frame for mounting the spout and the spout control mechanism, and for the support of the bags to be filled.

Another object is to provide a supporting structure for the bags to be filled that holds the bags securely in position while they are filled, and which may be operated to release the bags for automatic discharge upon completion of the filling operation.

These and other objects of the present invention will be apparent from the following description of the accompanying drawings which illustrate a preferred embodiment thereof and wherein:

Fig. l is a fragmentary perspective of a bag filling machine embodying the invention.

Figs. 2 and 3 are longitudinal sections through the spout and the spout control mechanism of the machine illustrated in Fig. 1 showing diflerent operational positions thereof.

Figs. 4 and 5 are front elevations, partly in section, of the spout and the spout control mechanism in the operational portions illustrated in Figs. 2 and 3.

Fig. 6 is a side elevation of the bag supporting mecha- "ice nism of the apparatus shown in Fig. 1 showing a filled bag in the process of being discharged therefrom.

Figs. 7 and 8 are combined hydraulic and electric circuit diagrams representing different operational positions of the spout control mechanism.

In Fig. 1 the reference numeral 10 indicates the bottom end of a tank 10 which rests upon a suitable pedestal 12. In said tank a supply of powdered or granular material is maintained in fluid like conditions in a well known manner by rising currents of air, the necessary quantity of air being delivered into the tank near the bottom end thereof through a suitable conduit 14. In the illustrated apparatus, the lower section 16 of the front wall 18 of tank 10 is forwardly tilted and has a discharge opening 20 (Figs. 2 and 3) through which the material may enter into an inclined spout structure 22. Said spout structure is composed of an initial portion 24 which is made of resilient material, and a terminal portion 26 which is made of rigid material and which for-ms the actual spout over which the receiving snout of the bag to be filled is engaged.

Portion 24 of the spout structure is formed by a short rubber hose whose opposite ends are extended into

annular flanges

28 and 30, respectively. Through flange 28 the hose 24 is suitably bolted to the forwardly tilted wall section 16 of tank 10 around the discharge opening 24) thereof, as illustrated in Figs. 2 and 4. The other flange 30 of said hose is secured by bolts 31 to an annular disk 32 that forms a part of a bag supporting frame 34, which is suspended from one arm of a scale 36 that is located in front of and below the tank 10. Secured to the opposite face of the annular disk 32 by the same bolts 31 that secure the flexible hose 24 to said disk, is the flanged end 49 of the actual spout 26, which may be made from steel, and which forms a downwardly directed discharge opening 42, as best shown in Fig. 2.

Associated with the spout 26 is a clamping mechanism 44 that may be manipulated to hold the receiving snout of a bag securely in engagement with the spout, as shown in Fig. 1. Said mechanism comprises the actual clamp 46 which has the formof a. shell segment of horseshoe-shaped cross section. Secured to the converging sides of said shell segment are rectangular rubber pads 48a and 4812 that project downwardly below the linear edges of said clamp segment and which are intended to engage the bag that is to be held on the spout. The shell segment 46 has a tail 50 that turns on a spindle 52 which extends transversely across the spoutand which is held in and between a pair of vertically disposed triangular shelves 54a and 54b. The shelves in turn are secured to, and project forwardly from, an upwardly directed bar-shaped extension of the annular disk 32. Springs 56a and 56b tensioned between the shelves 540, 54band studs 58a, 58b, respectively, that project laterally from the tail 50 of the clamp near the shell portion 46 thereof, urgethe clamp in clockwise direction, as viewed in Figs. 2 and 3, into a position wherein it is withdrawn from the spout so that the snout of a bag may be readily slipped over the spout.

Means are provided that may be manipulated to force to clamp with its rubber pads 48a and 48b over and into engagement with the snout of a bag on the spout so as to retain the bag in material-receiving position thereon. For this purpose a horizontal spindle 60 is rotatably supported in the crest points of the two aforementioned triangular shelves 54a and 54b above the juncture of the tail 52 and the shell segment 46 of the clamp. Rigidly secured to one laterally projecting end of said spindle is a downwardly extending operating handle .62. Likewise secured to said spindle 60 intermediately of the shelves 54a and 54b is a depending arm 64 which carries at its free end a roller :66 that engages the back of the clamp. When the arm 64 is in the counterclockwise position illustrated ,in Fig. 3, wherein its roller 66 rides over the tail 52 of the clamp, the springs 56a and 56b are permitted to raise the clamp into a position wherein it is withdrawn from the spout. When the spindle 60 is turned in clockwise position by raising the handle 62, however, the roller 66 depresses the clamp and forces the rubber pads 48a and 48b of its shell portion into engagement with the snout of a bag that may have been slipped over the spout 26, thus holding the snout of the bag securely against the flanks of the spout (Fig. 2).

The arm 64 and the clamp 46-52 in conjunction with the springs 56a and 56b form, in fact, a toggle, and when the operating handle 62 is raised to an extent Where the roller 66 on arm 64 has passed the plane determined by spindle 6t) and the studs 58a and 58b at which the springs 56a and 56b engage the clamp, said springs will actually urge the arm 64 in clockwise direction as viewed in Figs. 2 and 3. To avoid excessive clockwise rotation of arm 64 which would withdraw the roller 66 from the clamp, the spindle 60 carries firmly secured thereto another arm 68 that is provided at its free end with an adjustable contact stud 70. Said stud carries a metal disc 71 that is arranged to strike against the top edge of shelf 54a whenever the clamp has reached its position of closest approach to the spout. Thus, the clamp once brought down upon the snout of a bag engaged over the spout, remains dependably in bag retaining position until an operator lowers the handle 62 to its original downwardly extending position. When the clamp is in its bag retaining position, the contact stud 70 engages and depresses the actuating button 72 of a normally open switch 74 that lies in the power circuit of a solenoid 76. Said solenoid 76 controls the position of a pneumatic valve 78 which is supported from the front wall 18 of the tank and which in turn controls the supply of air from a source of compressed air (not shown) to a pneumatic cylinder 80. The cylinder is mounted upon a crescent-shaped mounting channel 81 secured by an arm 82 to the forwardly tilted section 16 of the tank wall 18, and said cylinder determines the positionof the mechanism that opens or closes the flexible hose 24, as will presently be described.

In accordance with the invention, mechanism is provided that holds the resilient hose 2 4 normally in the pinched or squeezed condition illustrated in Figs. 3 and 5 to block flow of the fluidized material therethrough, and which may be operated to release the flexible hose 24 temporarily to permit flow of the material therethrough. Said mechanism comprises a pair of horizontally disposed

rods

83 and 84 arranged above and below the resilient hose 24, that are normally held so close to each other as to squeeze the hose between them, and which may be withdrawn from said hose to permit it to reexpand and form a conduit for the passage of a fluidized material therethrough. To this end the upper rod 83 is rigidly attached to the normally downwardly projected piston rod 86 of the hereinbefore mentioned pneumatic cylinder 80, and the crescent-shaped mounting channel 81 journals in its opposite points equi-armed bellcranks 92a and 92b, respectively. Relatively short twin links 94a and 94b pivotally connect intermediate points of the upper pinching rod 83 to the inner ends of said bellcranks, while elongated twin links 96a and 96b connect the outer ends of said bellcranks to the outer ends of the lower pinching rod 84. Whenever the piston rod 86 of the hydraulic cylinder 80 is downwardly projected and pushes the upper pinching rod 83 into engagement with the resilient hose 24, as illustrated in Figs. 3 and 5, the bellcranks 92a and 92b are in the rotary position illustrated in Fig. 5, wherein their outer ends are raised. In this condition, they hold the lower pinching rod 84 through the links 96a and 96b in engagement with the resilient hose 24, so that the hose is completely closed, as illustrated in Fig. 5. When the cylinder 80 is operated to retract its piston rod 86, it withdraws the upper pinching rod 83 from the hose 24 and swings the bellcranks 92a and 92b in counter-clockwise and clockwise direction, respectively. This lowers their outer ends which is effective to withdraw the lower pinching rod 84 from the hose 24, permitting it to open fully under its own resiliency, as illustrated in Fig. 4. To prevent wobbling of the lower pinching rod during the described operation, guide bars 97a and 97b rigidly secured to and depending vertically from the opposite ends of the upper pinching rod 83 are engaged, and slide, between the individual members of the elongated twin links 960: and 96b, as best shown in Figs. 4 and 5.

To minimize the strain imposed upon the rubber hose 24 by the continual operation of the described pinching mechanism, and thus delay its deterioration, it would be desirable to make said hose relatively long since the continual deformation of its walls would in this manner be distributed over a relatively large area. However, fluidized material when escaping from the fluidizing tank through a discharge conduit, deaerates rapidly and loses the characteristics of a liquid. For this reason it would be desirable to make such discharge conduits as short as possible to assure free flow of the material from the fluidizing tank into the bag. In accordance with the invention I provide a hose construction for spouts, of the type referred to, that may be held as short as the mechanical dimensions of the pinching mechanisms will permit, and which yet will not be subjected to excessive deterioration by operation of the described pinching mechanism. Having reference to Figs. 2 and 3, the resilient hose 24 is formed with bellows-like folds 180 and 192 at either side of the smooth portion 98 that is engaged by the pinching

rods

83 and 84. By virtue of said folds the strain imposed upon the walls of the hose, as it is deformed by the pinching rods, is negligible and, though short in length, a resilient hose constructed as described and illustrated, will last for extended periods of practical use without appreciable signs of deterioration.

The hereinbefore mentioned supporting structure 34 for the bag comprises a substantially vertically disposed post 184 whose upper end 106 is bent to slant in parallelism with the forwardly tilted wall section 16 of tank 10. Rigidly secured to said slanted upper end 106 of post 104 is a downwardly directed bar-shaped extension 108 of the hereinbefore mentioned annular disk 32 to which the spout 26 and the hose 24 are secured, as previously described. Thus, the annular disk 34 is likewise disposed in a plane parallel to the forwardly tilted wall section 16, and the center axis of the discharge conduit formed by hose 24 and spout 26 extends at right angles to said plane and hence slants downwardly.

Directly below its bend line the post 104 carries firmly secured thereto two symmetrically opposed L-shaped arms 110a and 110b, the free ends of which are supported for limited rotational movement from the free ends of a U-shaped stirrup 112 that embraces said post and its L-shaped arms. The stirrup 112 constitutes part of the hereinbefore mentioned scale 36. Its side bars 114a and 114b possess at intermediate points laterally projecting ears 116a and 116b, respectively, that rest upon upwardly directed knife edges 118 (only one being visible in Figure 1) which are suitably mounted in and project upwardly from two horizontally disposed parallel girders 120a and 12% of the pedestal 12. A counterweight 122 is adjustably engaged over a threaded rod 124 that projects rearwardly from the connecting bar 126 of the U-shaped stirrup 112.

Due to the presence of the counterweight 122 the U- shaped stirrup 112 is normally tilted rearwardly on the knife blades 118 to an extent wherein a lug 128 mounted upon and projecting laterally from the cross bar 126 of stirrup 112, bears down upon and depresses the actuating button 130 of a normally open switch 132 that is mounted upon the adjacent girder 120b. Said switch 132 lies in the hereinbefore mentioned power circuit of the solenoid 76 that controls the position of the pneumatic valve 78,

and its significance in the operation of the bag filling machine embodying the present invention will be described in greater detail hereinafter.

At its lower end the post 104 carries an adjustable saddle 133 upon which the bags are supported during the filling operation. Said saddle comprises a rectangular sleeve 134 that is slidably received over the lower end of post 104 and which may be secured to said post at a variety of 'dilferent levels, depending upon the size of the bag to be filled, by means of a removable pin 136 that engages an aperture in said sleeve, and may selectively be engaged into any one of a plurality of vertically spaced apertures 138 provided in the lower end of said post. The sleeve 134 carries rigidly a forwardly projecting stud 140 within the free end of which is pivotally supported a U-shaped stirrup 142 whose upwardly directed parallel legs 144a and 14411 mount forwardly projecting bars 146a and 146b, respectively. The ends of the saddle bars 146:: and 146b, remote from post 104, are curved downwardly as shown in Fig. 1, and springs 143a and 148b tensioned between the opposite ends of said bars adjacent the post 104 and studs 150 projecting laterally from the bottom end of sleeve 134 urge said bars into the position illustrated in Fig. 1 wherein they come to rest upon the opposite ends of a cross bar 151 that is rigidly secured to the sleeve 134. In this position the saddle bars 146a and 14617 are substantially horizontally disposed. The saddle bars 146a and 14617 are spaced from each other by a distance suflicient to receive a collapsed bag therebetween, yet they are sufliciently close to each other to permit the lower end of a bag as it is filled with material from tank 10, to spread over and rest upon their horizontal runs. A buffer link 153 may be interposed between the post 104 and a cross-brace 155 of pedestal 12 below the level of the knife edges 118 to prevent excessive rotation of said post 104 during manipulation of a bag on saddle 133 which may harmfully stretch the flexible hose portion 24 of the spout structure 22.

When there is no bag upon the described bag supporting structure, the weight switch 132 in the power circuit of the valve control solenoid 76 is closed due to the elfect of the adjustable counterweight 122 on the position of the stirrup 112, as previously described. The clamp operated switch 74 in said same power circuit, however, is open so that the valve control solenoid 76 is -de-energized. When said solenoid is de-energized, a spring 154 in the valve 78 maintains said valve in the position illustrated in Fig. 8, wherein compressed air is directed into the pneumatic cylinder 80 above its piston 156 and the space below the piston 156 is connected to the outside. Under such conditions the force of the air above the piston and a strong spring 152 within the pneumatic cylinder 80 hold the piston in a position wherein the piston rod is downwardly projected and causes the pinching

rods

83 and 84 to close upon the resilient hose 24 preventing escape of any fluidized material from the tank to the outside.

In practice the operator may now place an empty bag into the space between the saddle bars 146a and 1461) at the lower end of post 104 and between the L-shaped arms 110a and 11012, and engage its snout over the spout 26. He then manipulates the handle 62 to close the clamp 44 fully upon the snout of the bag and the spout underneath so that the bag is securely held in engagement with the spout. As soon as the clamp 44 is fully engaged over the snout of the bag, the arm 68 on the operating spindle 60 of the clamp control mechanism brings the adjustable contact stud 70 against the operating button 72 of the normally open switch 74 in the power circuit of the valve control solenoid 7 6 and causes said switch to close. This completes the power circuit through the valve control solenoid 76 and causes energization of said solenoid. Energization of the solenoid 76 moves the control valve 78 into the position illustrated in Fig. 7, wherein the source of compressed air is connected to the cylinder space below the piston 156 while the cylinder space above the piston is connected to the outside atmosphere. As a result thereof, the piston rod is retracted against the urgency of spring 152, the pinching

rods

83 and 84 are withdrawn from the resilient hose 24 of the spout and said hose is allowed to expand (Figs. 2 and 4). Fluidized material may now flow through the spout under the weight of the fluidized column within the tank 10 and fill the bag upon the saddle 133; and as the bag is filled, its lower end begins to bulge, and rises above and spreads over the bars 146:: and 146mb of the supporting saddle so that it rests fully upon said bars.

As soon as the quantity of the material accumulating in the bag reaches a desired limit, which may be predetermined by adjustment of the counterweight 122 upon rod 124, the scale stirrup 112 tilts upon the knife edges 118 from its reclining to a forwardly declined position, and the actuating lug 128 on its connecting bar 126 releases the actuating button 130 of the scale switch 132 causing said switch to open. This interrupts the power circuit of the valve control solenoid 76. The resultant deenergization of said solenoid permits the valve to return to the position illustrated in Fig. 8 wherein it connects the cylinder space below the piston 156 to the outside atmosphere, while connecting the source of compressed air to the cylinder space above said piston. This, in conjunction with the force of spring 152, causes an extremely rapid projection of the piston rod which eflects almost instantaneous closure of the pinching bars 83 and 84 upon the resilient hose 24 of the spout structure. Thus, further supply of powdered or granular material into the bag upon the saddle 133 ceases almost instantaneously when the bag reaches its proper weight.

The bag may now be released by proper manipulation of the clamp control handle 62, and as soon as the clamp is withdrawn from its snout, it will slide off from the spout due to the inclined disposition thereof. When this occurs, the supporting bars 146a and 14612 of saddle 133 tilt against the urgency of springs 148a and 14% under the weight of the filled bag, since its center of gravity is located above the downwardly curved unsupported ends of said bars at a point further removed from the post 104 than the pivotal support of said bars in stud 140. The filled bag will, therefore, slide forwardly oil": from the saddle bars as illustrated in Fig. 6, and drop on a conveyor or trolley (not shown), with the L-shaped arms a and 11012 of post 104 acting to prevent accidental discharge of the bag in a lateral direction.

As soon as the filled bag has slipped off the supporting structure 34, the counterweight 122 returns the scale stirrups 112 to the rearwardly inclined position wherein the lug 128 bears against the actuating button of the weight switch 132 and closes said switch (Fig. 7). Thus, the mechanism is again in condition for commencement of operation as soon as the clamp 44 is closed over the receiving snout of another bag.

It should here be noted that the described arrangement is such that there can never be an uncontrolled discharge of fluidized material through the spout, irrespective of whether there is failure in the electric power that controls the pneumatic valve or in the supply of compressed air. If there should be a power failure, the solenoid 76 deenergizes immediately, or remains de-energized, as the case may be, causing the valve 78 to resume, or to remain in, the position illustrated in Fig. 7, wherein the spring 152 holds the piston rod of the pneumatic cylinder 80 in projected position, which is effective to close the spout. Similarly, if the supply of compressed air should fail, the spring 152 returns the piston rod to its projected position, or holds it in said position as the case may be, so that the spout will close or remain closed, preventing any uncontrolled escape of the fluidized material from tank 10.

While We have described our invention with the aid of an exemplary embodiment thereof, it will be understood that we do not wish to be limited to the specific constructional details shown and described, which may be departed from without departing from the scope and spirit of my invention.

When fiuidization of granular or powdered materials is referred to in the above given description and in the following claims, this term is intended to mean not only full fluidization of the said materials, wherein they behave entirely as a liquid, but also all those conditions of lesser aeration which reduce their natural angle of repose and will therefore permit said materials to flow down inclined surfaces that slant at angles less than their natural angle of repose.

We claim:

1. A discharge spout for fluidized solids comprising an initial conduit portion of resilient material and a terminal conduit portion of rigid material, said initial conduit portion having a section formed in the manner of a bellows and a smooth section, opposed members at either side of said smooth section normally held in a position sufficiently close to each other to deform said smooth section and block the flow of fluidized solids therethrough, a clamp movable into a position wherein it is effective to hold a bag in receiving position with regard to said terminal conduit portion, and means operative in response to movement of said clamp into bag holding position to withdraw said opposed members from said smooth section and thus permit flow of fluidized solids through said spout.

2. A discharge spout for fluidized solids comprising an initial conduit portion of resilient material and a terminal conduit portion of rigid material, said initial conduit portion having a pair of axially spaced sections formed in the manner of a bellows and intermediately thereof a smooth section, opposed members at either side of said smooth section normally held in a position sufliciently close to each other to deform said smooth section and block the flow of fluidized solids therethrough, a clamp movable into a position wherein it is effective to hold a bag in receiving position with regard to said terminal conduit portion, and means operative in response to movement of said clamp into bag holding position to withdraw said opposed members from said smooth section and thus permit flow of fluidized solids therethrough.

3. In a machine for filling bags with powdered or granular material having a material supply tank, means for fluidizing the material in the tank, a discharge spout, a conduit leading from said tank to said spout and a scale; a supporting structure for the bag to be filled comprising a substantially vertically disposed post, means pivotally supporting said post at a point intermediately of its ends from one side of the scale, an annular disc or rigidly mounting the discharge spout in a declining position at the upper end of said post, a support for the bag pivotally supported from the lower end of said post, and releasable means supported above said annular disc for clamping the material-receiving snout of a bag onto the spout.

4. In a machine for filling bags with powdered or granular material having a material supply tank, a discharge spout, a conduit leading from said tank to said spout and a scale; a supporting structure for the bag to be filled comprising a substantially vertically disposed post, means pivotally supporting said post at a point intermediately of its ends from one side of the scale, an

annular disc for rigidly mounting the discharge spout in a declining position at the upper end of said post, a support for the bag including a pair of substantially horizontally extending parallel bars for movement about a transverse horizontal axis, means pivotally supporting said bars from the lower end of said post at a point in front of said post yet closer to said post than the center of gravity of a filled bag resting thereon, and releasable means supported from the upper end of said post above the spout for holding the material receiving snout of a bag onto the spout.

5. In a machine for filling bags with powdered or granular material having a material supply tank, a discharge spout, a conduit leading from said tank to said spout and a scale; a supporting structure for the bag to be filled comprising a substantially vertically disposed post, means pivotally supporting said post at a point intermediately of its ends from one side of the scale, an annular disc at the upper end of said post for rigidly mounting the discharge spout in a declining position, a support for the bag including a pair of substantially horizontally extending bars having downwardly curved outer ends, said bars being spaced transversely at a distance sufiiciently wide to receive the lower end of an empty bag therebetween, but sufliciently close to cause the lower end of a filled bag to spread over and rest on said bars, means pivotally supporting said bars from the lower end of said post at a point closer to said post than the center of gravity of a filled bag resting thereon, and releasable means supported from the upper end of said post above said annular disc for holding the materialreceiving snout of a bag onto said spout.

6. For a bag filling machine having a fluidizing tank, a discharge spout at the lower end of said tank, a conduit leading from said tank to said spout, and a scale; a supporting structure for the bags to be filled comprising a substantially vertically disposed post, means at the upper end of said post for rigidly attaching the spout thereto, substantially horizontal bars pivotally supported from the lower end of said post for tilting movement under the weight of a filled bag into a position wherein they slant downwardly away from said post, spring means yieldably holding said bars in their horizontal bag supporting position, releasable means for holding a bag resting upon said bars with its material-receiving snout in engagement with said spout, and a pair of L-shaped arms rigidly supported from said post at an intermediate point thereof to form lateral guides for a bag supported on said bars to confine movement thereof upon release of said holding means to the plane of rotation of said tilting bars, the free ends of said arms being pivotally supported from one side of said scale.

References Cited in the file of this patent UNITED STATES PATENTS 2,183,835 Foulke Dec. 19, 1939 2,317,865 Talbot Apr. 27, 1943 2,371,434 Eppler Mar. 13, 1945 FOREIGN PATENTS 503,351 Great Britain Apr. 5, 1939 1,056,327 France Feb. 25, 1954