US2638305A - Weight proportioning means and method - Google Patents

Description

y 1953 R. L. MILLER "2,638,305

WEIGHT PROPORTIONING MEANS AND METHOD Filed April 4, 1949 SSheets-Sheet 1 INVENTOR; Rofierl L ,Miler ATTORNEY May 12, 1953 R. L.. mum 2,638,305 WEIGHT PROPORTIONING MEANS AND METHOD Filed April 4, 1949 Y 3 Sheets-Sheet 2 IN VEN TOR.

flab e rt L. Mllel ATTOR/Vf) R. L. MILLER WEIGHT PROPORTIONING MEANS AND METHOD May 12, 1953 3 SheetS Sheet-B Filed April 4, 1949 WE u 1 NE F. r ll r e Rd m M 8 v D 0 R M Y B Y E M m T A Patented May 12, 1953 WEIGHT @BROPORTIONING .MEANS ZAND METHDD Robert L; Miller, Berkeley, Calif.

Application ApriliA, 1949, Sel'ial'No..86,9Z4

.10 Claims. I

This invention relates to a method of and l means for proportioning; blending-and packaging to a desired weight a mixture -.o a plurality of dry materials having difierent particle. sizes and particularly to such-a. method; and means which will accomplish such objects .rapidlyandeconomically.

The packaging of-many widely used mixtures requires the blending of-amluralityiof materials having particle sizes may vary over a chamber to, fill. a number of packagesiof the desired finished mixture-fromoneloading-of said chamber, since the time and labor-involved in each loading prohibitstheeconomical use of such a method shouldthemixer .be; loaded in single package lots.

However, any such. batch process encounters the problem of segregationof thevariously sized ingredients particularly where drzymaterials are being blended. .Itcanibeseenthat it wouldnot be possible .to draw off uniformly composed .single packages of a dry mixturejfrom such abatch process since the larger particles would tend to leave the rotating -chamhercfirstand the .finer particles tend to concentratejn the materials remainingbehind in .thechamben. Thus, in.the case of a mixture such .as dryconcrete, where at least three separate. ingredients are. mixed,.ranging in size from rock orgraveloiaboutione inch diameter down to Portland cement passing through a 200 mesh screengitcan beseen that the problem of segregation would The presentito a degree that would prechide..the useof such a batch process where. such .a.mixture is to .be ac curately packaged.

It is therefore aiundamentaipbject of the .inventicn herein disclosed -to provide a means for the proportioning,1.blending and uniform .packaging to weightof a.mixture'.of several'dry gredients having widely .difierentparticle sizes wherein each such package of; the-.mixture is .of the same composition and.- weight.

In: order to economically, package' a. mixture :'of low cost ingredients in'a packageofsrelatively large weight, itisessential that the-.manualioperations be, .kept to a. minimum; This :factor: is particularly emphasized at the present .time by.

the large and-increasingg-costs:dhlabor; :sAuiur-- ther advantage and. object of the invention herein described, therefore is the'proportioning, blend- .ing. andpackaging to weight of a mixture in a .fast and-economical operation requiring a minimum .of manual guidance.

mentioned-above, in order to economically package a mixture of lowcost ingredients,.it is essential. that .manu-al operations be kept to a minimum. Onesuch manualoperation, which is desirable to eliminate,,isthat of closing the top of-an-openmouth bag by either sewing or tying in a. suitable manner. Avalve type-bag eliminates this closing operation. Due -.to its construction, utilizing-a tubular .valve type bag can best beeffected where the materials to be placed therein are directed into the valve opening'ina steady stream flowing for a short timeinterval, said. stream possessing appreciable velocity such as would result.fromtheimaterials falling freely for .a short .distancehefore entering the valve tube.

Should the-proportioni 'lg v apparatus be of the typethat discharges. the total contents of .the bagina single. mess -the resultis that the valve opening ofthe bag is chokedby the sudden rush of .themixture intothe tube. The mass of materi'allthen accumulates .in and above the valve tube. and,v since. the; material has lost its velocity .byLbeing. halted momentarilyin its passage to-the bag the mixture dribbles, slowly through the tube into the .bag This slows down the; filling of .the' bag. and prevent such filling without manualiaid.

It-i's therefore aifurther object of this invention to provide a meansfor proportioning, blending and packagingia. mixture-era plurality of'm aterials ina valve type.= begin-aymanner that will feed .theimixture-quickly into and through the tube of such a valve type bag without choking the tube. The invention therefore ,possesses zthe further advantage of eliminating' the.additional manualeffortofsclosing the open mouth type :bag by substituting therefor: the .q-uick closing va'l-ve type bag.

it is 'sometimes I desirable, .in the use of machines of this type, to move the machineeit-her to. set it for. drawing materials. from other'storage bins .or tousethe-storage bil'lSLfOT-OthGI' purposes. It is therefore a further advantage and bject of. the present inventiontmprovide aportable unit which will vaccomplishall:o'f theforegoing objects andiadvantages.

Obviously, ,thereuarei some: mixtures which may require. a largeimlmber of separ-ate'ingredients in theirsfonmation'iandtblending. In the past it has been generally necessary to cluster all of the storage bins for the variously required materials around a centrally located proportioning and blending means. Due to this requirement, there has been a, definite limit as to the number of storage bins of different materials and an associated limit upon their size. Conversely, due to the characteristics of this invention, it is an advantage and object to provide a method and means to accomplish all of the foregoing objects and advantages While at the same time being adaptable to the blending and proportioning of an infinite number of ingredients in a mixture by eliminating the need for clustering the various ingredients about such a centrally disposed mixing and blending means.

In the marketing of packagedmixturesit is essential that every package be of identical composition and substantially the same weight. To ensure such identical composition, it is necessary that some means be employed to individually weigh all of the separate ingredients that go to make up the packaged mixture before said separate ingredients are blended and packaged. Accordingly, it is a further object of this invention to provide a means of individually weighing each ingredient of a mixture in conjunction with the blending and packaging thereof providing thereby identically composed packages of the said mixture in uniform weights.

Further objects are to provide a construction of maximum simplicity, economy and ease of assembly and disassembly and such further objects, advantages and capabilities as will later more fully appear and as are inherently possessed by the device and invention described.

The invention further resides in the combination, construction and arrangement illustrated in the accompanying drawings and while there is shown therein a preferred embodiment, it is to be understood that the same is capable of modification and change and comprehends other de tails, constructions, and uses without departing from the spirit of the invention or the scope of the appended claims.

The embodiment of the invention illustrated in the accompanying drawings and described herein is designed primarily for the proportioning, blending and packaging of dry mixtures containing cement but it is not intended to limit the use of the invention in any way by such illustration as it is believed that the same is adaptable to many other uses particularly to the proportioning, blending and packaging of any type of free flowing materials.

Referring now to the drawings:

Figure 1 is a side elevational view of the preferred form of the device of the present invention.

Figure 2 is an end elevational view, from the delivery end of said device.

Figure 3 is a fragmentary transverse sectional view taken on the line III-III of Figure 1 and looking in the direction of the arrows.

Figure 4 is a top plan view of the bagging section of the said device.

Figure 5-is an idealized diagrammatic section of the mounding of materials in layers on the belt.

Figure 6 is a schematic wiring diagram for the automatic operation of the device.

Referring now more particularly to the drawings forming a part of this specification, and in which like numerals are employed to designate like parts throughout the same, hoppers ll, 12

and I3 are set to receive and contain three separate materials which are to be blended by the action of the device, assuming there are three ingredients to be weighed, mixed and packaged. Suitable means, not shown, are provided to secure the said hoppers I i, 12 and I3 in place above the device as shown, and other means, also not shown, are provided to provide and maintain a supply of material in these hoppers so as to insure a satisfactory flow of material to the machine at all times. The said hoppers ll, l2 and i3 are mounted along a single center line, and at the same level over the machine, generally designated as I0.

The frame ID for the machine of the presentinvention as shown in the side view in Figure 1, consists of a rectangular box-like angle iron structure composed of legs I disposed at each corner thereof, and suitable diagonal braces l5. Identical side members l6 and I8, which are parallel to each other and to the floor level, cooperate with diagonal braces !5 to form a rigid trussed structure. The bottom chord members l6 form a motor support. Suitable cross members I9 connect and are perpendicular to these side members l6 and 1B for additional strengthening of the entire frame structure.

At the rear end 20 of upper members [8 there are mounted two identical adjustable bearing supports 2|, one on either side and parallel to each other, the center lines of said supported bearings being adjustable by the set screws 22. Rotatably secured in said bearings 2| by axle 23 is a large belt pulley 24. At the front end 25 of said upper side members I8 a similar but nonadjustable set of bearings 26 are mounted on the upper side of said members l8, parallel to eachother and with identical center lines perpendicular to said side members l8 and parallel to the center line of the rear pulley 24. On an axle 28 the head pulley 29, identical with pulley 24, is rotatably secured in said bearings 26.

Horizontally spaced between the opposing pulleys 24 and 29 on the upper side members l8 are three identical platform type scales 30, 3| and 32, the platforms 33 of which support a section 34 of free running parallel rollers 35. The top running surfaces of each of said rollers 35 and each of the sections 34 and the top of the running surfaces of the pulleys 24 and 29 are on a common horizontal plane parallel to the upper edge of the side members IS. The roller sections 34 are composed of opposing parallel angle iron side pieces 36 secured to the opposite sides of the scale platforms 33 in any suitable manner such as bolts 38 as shown in Figure 3. Spaced holes are cut in said side pieces 36 to accept and secure the axles 39 of each of the rollers. Said rollers 35 are identical in length to the large pulleys 24 and 29 in order to accommodate a common belt 40. This common'belt 4!! is a wide endless type and circulates about the two opposing pulleys 24 and 29 and over the top of rollers 35 on the scale platforms 33 returning beneath the structure, supported by suitable intermediate return rollers 4!. Similar intermediate rollers 42 are secured to the side members It on vertical uprights 43 and are set so that their upper running surfaces are on the same plane as all other belt supporting surfaces. Uprights 43 extend upwardly and cooperate with identical uprights 44 parallel thereto and spaced therefrom to form the support for the rectangular frames 45 establishing a bridging member over the belt 40. Each of these frames 45 is spaced equally from one another above the side members 6. Secured u on each of these bridges 45 over the exact "center of the belt 40 are standard magnetic vibratory feeders 46, 48 and 49, respectively. These feeders '46, 48 and 49 are powered by individual electro-m-agnets 50 mountedon a base 5| beneath the trough 52. A leaf spring link 53 runs between said magnet 50 and the forward end of said trough 52 for transmittin the vibratory force thereto. Ihe opposite or rear end of the trough -52 is supported by another leaf spring 54 on the base 5|. This base 5| is provided with front and rear mounting brackets 55 for securement and support of said feeder on bridge '45.

The hoppers ll, 12 and 13 respectively are so placed with respect to the feeders 46, 48 and 49 that the discharge openings 56 of each of said hoppers is positioned within the rear closed end of the trough -52 above the floor level thereof. This arrangement of'the discharge openings 56 within the troughs 52 is such that the material within 'said openings 56 chokes any flow therefrom by building up a small pile from the door of the trough 52 under said openings 56. Differential vibration of the trough 52 by means of rectified power acting upon the electro-magnet 5. causes the material within the trough to flow forward and pour from the open end thereof. Such vibration immediately dissipates the small pile of choking material under the openings 56 thereby allowing said openings 56 to admit material to the trough '52 at a rate of flow which is automatically set by the movement 'of material along said trough 52 by said differential vibra- 'tion.

Each of the scales 3'0, 31 and '32 is equipped with a micro switch '58 whose contacts are closed by the movement of thebeam 59 of said scale when said beam is brought to balance position. "The scales 39, 31 and 32 are positioned so that the discharge from each of the feeders 4 33 and '49 is deposited in the exact center of the roller sections 34 which are supported by said scales. In this manner the discharge of feeder 46 is deposited and weighed by scale 30, the discharge from feeder 48 by scale 3| and the discharge from feeder 49 by scale 32.

Each of the feeders 46, 48 and 49 is powered thru an individual cable '60 which connects with a common rigid conduit '61 attached to side memher 'I 8 and which carries electrical leads from the rectifier panels '63, 6'4 and 65 which are supported on a panel board 65. A magnetic 'type vibrator "68 is located upon the side near the lower end of hopper 13, which for the purposes of this description contains cement, in order to vibrate the material within the hopper and thus maintain it in a free flowing state. This vibrator 68 is also connected to the rigid conduit 6| by a cable and is supplied with power by rectifier unit 69.

The length of belt 49 and consequently the length of the entire machine '10 is based and is dependent upon the distance between the various feeders 46, 43 and 49. Said belt 4B is divided into segments each equal to the distance between feeders by spacing blocks ll which are mounted on the upper surface of said belt '40 near one edge. These blocks I I are set to cooperate with and. engage the limit switch 12 which is secured on the r'eai'most upright 43 in a position so that its actuating lever 13 will be operated by the passage of 'sa'idblock ll beneath it.

The head pulley 29 is directly connected through its axle 2B 'with a sprocket l'4 and-said sprocket is driven by means of a chain cooperating with a. drive sprocket 46 secured to the shaft of a motor 18. Due to the nature of the duty cycle imposed upon it, the motor 18 must be of the three phase type and it 'is mounted, as previously me'ntioned, on lower chord members [=6 -At the front =or discharge end 25 'of the ma' chine I0, a collecting hopper 79 is secured to the side members 18 in such a position that all material carried on the belt 40 over the pulley '29 is deposited in said hopper l9. In position below the discharge end of the hopper 19 two "uprights -38 are secured on the front legs M by the brackets 80 and on the forward end 25 of the members [8. As shown in Figure 2, these uprights 8D support two horizontal rails 8-! and 81 parallel to each other and lying in a plane perpendicular to the line of travel of the belt All. Hung from vertical wheels 82 engaging upper rail 8| and from horizontal thrust wheels 83 engaging rail 8| is the bag support carriage 84. The bag support carriage 34 is a rectangular angle iron frame with right angle brackets 85 at the upper "end thereof supporting the'deflecting hoppers 86 and H5. The deflecting hoppers 8E and 86' are inset into inclined tubular bag filling spouts 88 and t8 possessingconventional lever operated bag clamps cc and '89".

The bag filling spouts 88 and 88' are formed to accept the sleeve of a conventional valve ty pe paper bag 90 of the tuck-in sleeve style so that the clamps 8 9 and 89' may secure such a bag thereon by clamping said sleeve against the spout 88. The lower end of the bag 99 rests upon a supporting shoe 91 which is directly under the spout 88. A similar shoe 91' is located directly beneath spout 88" on the common frame 92 which is vertically adjustable by means of the cooperating bolts and holes 93 in the lower end of the carriage 8'4. It is therefore possible to shift "the carriage 84 horizontally beneath the hopper 19 so that either of the deflecting hoppers 86 or 86 is directly beneath the discharge opening 79 of said collecting hopper 19. This bottom discharge opening 19 is formed to an open cross sectional area ofa size to prevent the discharge of material therefrom at a rate and volume such as would clog the narrow spouts 88 and'88.

Conveniently located to the side of the carriage '84 on the leg i4 is a push button box 334 appropriately connected to the control panel board 611 by conduit 94'. The motor l8is also appropriately connected by conduit 78' with the motor star-ter 148 also located on the control panel board 66. Power cable 9b which supplies the three phase electrical power to the motor starter 148 is equipped with a conventional plug-in type connector 56'. The cable '88 supplies volt current to the device and 'is also equipped with a suitable plug-in type connec'ter as. It is to be noted'that the plug-in type connectors facilitate movement of the device It as a portable unit of equipment.

The electrical s stem shown in Figure 6in detail utilizes a common neutral wire 1'00. Electrical power for each of the half-wave manna- units 63, 64, 65 and 89 is supplied by separately fused taps off power-source m1 so that the identical leads 102 supply each rectifier. "The aim tab 103 01f power source it! supplies power for the control circuit and possesses a, manual switch 104 fordisconnection. In addition, each of the wires T82 possesses an identical manual switch 1'05 permittingindividual control of the 'i'ec'tifier Dower.

Each of the three rectiflers 63, 64 and 5 are electrically conneeted "to their respective feed'e'rs viously, power is conducted from main lead IOI through lead I02 across manual line switch I05 to rectifier 63. This circuit is completed to the common neutral wire I through lead I06. Wire 'I08 conducts rectified power from rectifier 63 through switch I09 into wire H0 thence through wire I I I into the electro-magnet I I2 of feeder 46. This circuit is completed back to rectifier 63 through wire I I3.

The manual load switch I09 is by-passed by another circuit which starts from the rectifier at Wire I08 passing through wire I I4 to the movable contact arm H5 of a mechanical locking electrically reset relay H8. The other side II6 of the movable contact arm H5 is connected through the line H9 to the wire I II loading to the feeder 46. This movable contact arm I I5 is operated by the energization of the coils I20 and I2I of the relay H8 by the actuation of the control circuit described below. Each of the other rectifiers 64 and 65 is connected exactly as i rectifier 63 with their respective feeders 48 and 49. In this manner the circuit between rectifier 63 and feeder 46 is completed by the energization of coil I20 in relay H8 pulling movable contact arm H5 into contact with point I I6. Similarly, relay I22 completes the circuit between rectifier 64 and feeder 48 and relay I23 completes th circuit between rectifier 65 and feeder 49.

The hopper vibrator 68 is energized by rectifier 69 which is identical with the other rectifiers 63, 64 and 65. Rectifier 69 draws current through power lead I02 from line III'I across line switch I05 and completes its circuit through the common neutral wire I00. Rectified power is drawn from rectifier 69 to the hopper vibrator 68 through wire I08 across load switch I09, thence through line H0 into the hopper vibrator electro-magnet 68, completing the circuit through line H3.

The rectifiers 63, 64, 65 and 69 are adjustable in direct current output by rheostat I01 connected therein in a conventional manner. It is therefore possible to control the amplitude of vibration of each of the electro-magnets I I2 in the feeders 46, 48 and 49 and the electro-magnet 68 in the hopper vibrator 68. Thus, individual control of the rate of flow of material in each of the feeders 63, 64 and 65 and of the intensity of vibration of hopper I I is achieved by adjusting said rheostats I01. As is well known to one skilled in the art, the rate of flow of a given material along a differentially vibrating trough 52 depend upon the amplitude of vibration of said trough when the feed conditions into said trough are held constant. By experimenting with the rate of flow of the various ingredients of the mixture involved, it is possible, therefore, to set the direct current output of each of the rectifiers so that the feeders will each supply a preselected amount of said ingredient in approximately the same length of time.

Coils I20 of the relays H8, I22 and I23 receive their power from the control power wire I84 in the following manner. Line I24 draws power from line I04 through jumper I25 to contact I26 of one side of the double pole double throw limit switch I2. The other contact I28 is connected by line I29 to the common lead I30. Coils I20 in each of the relays H8, I22 and I23 draw their power through leads I3I from the common wire I30 and the circuits through coils I20 are completed to common neutral wire I00 through leads I32. In this manner, closing of the contacts I26 and I28 simultaneously energizes each of the coils I20.

Wire I24 also supplies the power for the motor starting control circuit by conducting power from line I04 to contact I33 on the second side of the limit switch 12. This limit switch I2 is maintained normally with contacts I33 and I34 closed by the tension of spring return I2. From contact I34 through wire I35, control power is conducted to movable contact I36 in relay H8. Opposing stationary contact I38 is connected by line I39 with movable contact I36 in relay I22 and opposing stationary contact I38 in relay I22 is connected by line I48 with movable contact I36 in relay I23. Opposing stationary contact I38 in relay I23 is connected by line I41 with one side of normally closed pushbutton I42. The other side of this pushbutton I42 is connected by jumper I43 with one side of normally open pushbutton I44 and also by line I45 with one side of the sealing switch I46 in magnetic motor starter I48. The other side of sealing switch I46 is connected with the opposite side of normally open pushbutton I44 by line I49. The circuit is completed to common neutral wire I00 through solenoid I58, which actuates the magnetic motor starter I48, through the wire I5I. It should be noted that the contacts I36 and I38 in each of the relays H8, I22, and I23 are wired in series with one another and also in series with the normally open motor starting pushbutton I44.

Coils I2I of each of the relays H8, I22 and I23 draw power from line I04 through wires I52 across micro switch 58 on each of the scales 30, 3| and 32 and through line I53 into said coils I2I completing their circuits to the common neutral wire through lines I54 and I32.

The three phase motor I8 is energized along power wires I55, I56 and I58 through the contactors I59 of the magnetic starter I48 and is grounded through the line I60. Magnetic starter I48 is maintained in an open position by the tension of spring I48 when the solenoid I50 is not energized.

Prior to operation of the device, the balance arm of each of the scales 30, 3I and 32 is preset. For example, in the manufacture of a dry concrete where a bagged mixture containing 30 pounds of sand, 45 pounds of coarse aggregate and 15 pounds of Portland cement is desired, the scales are set as follows:

Scale 30 is set to come into balance and close micro switch 58 when a total weight of 30 pounds plus the constant tare weight of the roller section 34 and the portion of the belt 48 supported thereby are imposed upon it. Similarly, scale 3I is set to come into balance and close its respective micro switch 58 when a total weight of '75 pounds plus the constant tare weight of its roller section 34 and the portion of the belt 40 supported thereby are imposed upon it. As described later, this 75 pounds is made up of a layer of 30 pounds of sand and a layer of 45 pounds of coarse aggregate. Scale 32 is set to come into balance and close its respective micro switch 58 when a total weight of pounds plus the constant tare weight of the roller section 34 and the portion of the belt 40 supported thereby are imposed upon it. This 90 pounds, as described later, is made up of a layer of 30 pounds of sand, a layer of 45 pounds of coarse aggregate and a layer of 15 pounds of cement.

For the purpose of this operational descriptien, we will assume that. the. machinev has. been in operation and that each. of the scales 30., 3|; and 32 is appropriately weighted with material.

as described. above. In this position. each of the micro. switches 58 is: closed.

Each. of. the hoppers II, I2 and I3 is filled with its respective material, 1. e. sand; coarse. aggregate and cement. The line switches. I05 of each of the rectifiers 63, 64, S5- and 6.0 are closed, and the rectifying units. allowed to.' warm up. Load switches I09. on the feeder rectifier units 63, 64 and G5. are only used when. it is desired to operate one of the feeders manual- 1y. Line switch. I04. is closed to admit. power to the control. circuit. Load switch I09. in rectifier 69 is closed to actuate vibrator G8 which. is. mounted on the side of hopper I3.

A bag 90 is clamped in filling. position on the spout. 88 and the carriage 8.4 is positioned under the collecting hopper I9 so as to receive its discharge in deflecting hopper 88.

Since the three micro switches 58. are. closed on each of. the scales 30, 3| and 32, the reset coils I2I in each. of. the relays I18, I22 and I23 is, energized by power flowing from line I04 through lines I52 across micro switches 58' through lines I53 into. coils I2I. and back to neutral line I00 through leads I54 and leads I32.

The device is now ready for production operation and the operator presses the pushhutton I44- Closing. of this pushbutton I44 allows current to fiow from power line I04 through line I24,v across. contacts I33: and I34, through line I35, across closed contacts I36 and I38 in relay II=B From contact I38 in relay II8', the current flows through. line I33 across closed contacts I36 and I38 in relay I22, theme by line I40 to closed contacts I35 and. I38. in relay I23 and through line I4.I to normally closed pushbutton. I42. Since pushbutton I42 is normally closed, the current flows across it into line I43, thence through pushbutton I44,v momentarily manually closed by the operator, through line I48 into. solenoid I50. The solenoid I50 is energized and this circuitis completed to the common neutral line I00 by going through line I-SI.

The energization of solenoid I50 against the spring. I48 acts to simultaneously close contactorsv I59 and sealing switch I46 in the magnetic. motor starter I48. Three phase current then flows through the lines I55, I56 and I58 across contactors I59 into motor I8 starting said motor. Even though the pushbutton I44 is only momentarily depressed. by the action of the operator,. sealing switch I45. allows solenoid I50 to remain energized by current. flowing through line I.4.5.. As the motor I8 is now running, the belt 40 is moved by the action. of the driving sprocket 7.6, the chain 75, the driven sprocket I4 and. thence through pulley 29 to the belt 40'. Motion of the belt 40 carries the three piles of material IBI, I62 and I63forward.

Forward movement of the. piles I.6I,. I62 and I-631 from above the scale platforms 33 unhale ances the. scales-30, 3i and 32.; the beams 59.. drop down, allowing the micro switches 58 to open and thus de-energizing; the reset coils I:2,.I.. Belt. 40 continues to. move under the power of the motor. I0 until a belt spacing block II momen tarily actuates the limit switch I2 against the tension of the spring return 1.2.. Actuation of the limitswitch- 72 opens the circuit established. across the. contacts: I33 and I34 by the original pressing ofthe pushbutton I44, thus de-encr gizing the. solenoid I59. and. allowing. the spring return. I48 to, open the magnetic. motor, starter I48 which. stops the motor 1.8.. Stopping. of the: motor "I8. stops the motion ofthe. belt. 40. Since the spacing blocks 'I'I mounted on. the belt. 40; are. spaced the. same. distance apart, as. are, the, feeders 4.6., 48 and 49,, the belt. 40 has. moved a. distance equal. to the spacing between. the, feeder ers 46, 48 and. 4e. and consequently the. realwardv two piles of 'roaterial IM and [.62 have. advanced to new positions under the front two. feeders 4B. and. 4.9 and the front pile IE3 is carried over the. head pulley Z9 and falls into. the collecting hop per I9.

The. actuation of the limit switch I2 momentarily completes a circuit. across the, contacts: I26 and IE3, allowing current. to flow. from power line. I04. through line I24, through jumper I25; across contacts I26 and I28, through common line I and lines I3! intov coils I20. of. relays: II8,. I22 and I23, thence through lines [.32. to; neutral. line I00 completing the circuit. and. energizing, the. coils I20. The momentary energization of coils I20 draws the movablev contacts. M5 to the contacts H6 and completes the. by pass load circuits. to the feeders 4E, 48. and 43..

As mentioned previously, the operator has, closed the, line. switches I05 on. each. of, the reetis fiers and current. flows from lines I02. across the. line switches I05 into thev reotifiers. and. returns. to the common. neutral wire I00 through. the linesv I051. By establishing the by-pass loadcircuit, by the closing of. contacts II 5 and IIG, direct rectified. power flows from rectifiers 63', 64-. and. 55. through the lines.- I.0.8. and H4. across. contacts. H5 and IIB, through lines. II9. and. III. into. 00.1 5- H2 of each of. the. feeders 43,. 4.8. and. 43. and, re,- turns to the rectifiers through lines H3. Thus. all three feeders. are simultaneously energized and the materials begin to flow therefrom. and deposit upon the belt at the. several weigh. points. Since relays. IIB, I22. and. I23 are of the. mechanical. locking, electrically reset tyne even though the energizing of. the. coils I20 is but momentary, the. circuits. closed across contacts. I.I.'.5.. and IIS remain established. until the reset. coils. I12 I: are. re-energized by the closing of the micro. switches. 58,. as. will be described later. The feeders. continue to deposit material upon the; belt. 4.0. beneath them until the weights. reg.-v istered. upon the: scales 31), 3I. and 3-2 reach the. preset limits and the scale beams 58. rise. to. balance position. thereby closing micro. switches-- 58. The; closing. of micro switches 58. results; inthe energization of reset coils IZI which. swing the movable contact arms breaking the circuit across points II5 and H6, thus. shutting off. the feeders. 40, 4B and 49.. and establishing the cir.-. cuit acrosspoints I36 and I38. While all feeders. are. energized simultaneously, it should be noted thatv they will shut off individually depending upon the. rate. of deposition of material. upon. their individual. scales 30, 3! and 32.. An. attempt is; made to roughly adjust the rates of flow from all feeders by varying the setting. of the rheostats I01 so. that the desired weights of mate.- rials will be deposited in approximately the same. time. intervalupon all scales.

The operator having pressed the pushbutton I44 has caused the. belt 40 to move forward into. the neat loading position which results. in the front pile I53 being. carried over the head policy 29 and'into thecoll'ecting. hopper III.

As shown in Figure 5,. since the deposited front 7 pile. I63 consists. of a. primary layer I64 of sand.

deposited upon the belt 40 by the feeder 46, a secondary layer I65 of coarse aggregates deposited upon the sand layer I64 by the feeder 48 and a third layer I66 of cement laid on top of the secondary layer I65 of coarse aggregates by the feeder 49, and since the falling of this pile I63 through the collecting hopper 19 has a commingling action, the resulting mixture which flows through the deflecting hopper 86 and is directed into the bag 96 through the spout 88 is of a generally blended and uniform cross sectional composition. This layered deposition eliminates the necessity of using the familiar bafiie method of blending in a collecting hopper.

It is to be noted that this method of depositing the ingredients upon the belt 48 in successive layers, as illustrated in Figure and as described, may be further refined to assure even more uniform cross sectional composition by the addition of horizontally spaced spreading and leveling bars I68, as shown in Figure 2. These bars I68 are vertically adjustable on uprights I69 and secured parallel to the upper surface of the belt 40. In this manner, each pile I6I, I62 and I63 is leveled by a blading action of the bars I68 as the pile is carried forward to its new position. Thus the final three layered pile I63 which is carried over the head pulley 28, consists of individual layers of the same general area, but differing in thickness.

While the pile I63 is being deposited in the bag 90, which is clamped on the spout 88, the operator slides the valve opening of an empty bag over the spout 88' and clamps it in place by the clamp 89. As soon as the bag 90 has received the total contents of the hopper I9, the operator unloosens the clamp 89 and removes the bag 90 from the spout 88 and horizontally shifts the carriage 84 to the other filling position, wherein the deflecting hopper 86 is directly under the discharge opening 19' of the hopper 19. The operator then presses the pushbutton I44 again, which initiates another cycle as described above.

It is to be noted that should the operator attempt to press said button I44 prior to the time when each of the feeders 46, 48 and 49 has deposited the desired preset weight of ingredient upon the belt 40 to bring each scale 36, 3| and 32 into balance, the series connection of contacts I36 and I38 between the relays II8, I22 and I23 and said pushbutton I44 prevents such premature pressure of the pushbutton I44 from completing the starting circuit and operating the motor 18 starting movement of the belt 40.

I claim:

1. The method of combining, prior to mixing, a plurality of dry ingredients having different particle sizes to form a mixture having a predetermined composition by weight which includes the step of providing equally spaced separate weighing and loading stations for the delivery of each ingredient, the step of controlling the deposit of each such ingredient onto an intermittently movable endless belt by weighing through the belt while the belt is at rest at such stations, and moving the said belt to the next weighing and loading station as soon as the cumulative weights of the said layers of ingredients presently and previously deposited on the said belt have attained predetermined values.

2. The method of proportioning and packaging mixtures of dry ingredients which comprises depositing a predetermined weight of each of a plurality of different ingredients in layers onto an intermittently movable belt while the belt is at rest, intermittently moving the said belt between predetermined loading and weighing stations to form in stages layered mounds of substantially uniform weight and composition for each state, blending and mixing each completed layer mound by successively discharging it into a collector at the discharge end of the conveyor belt, and feeding the said blended ingredients in the said collector into a sack container before the next mound of material is dis charged into said collector. g

3. The method of proportioning and packaging mixtures of dry ingredients which comprises depositing a predetermined weight of each of a plurality of ingredients having different particle sizes, in layers onto an intermittently movable conveyor belt while the said belt is at rest, intermittently moving the said belt between predetermined loading and weighing stations for accumulating by successively deposited'increments layered mounds of predetermined weights and substantially uniform composition, mixing and blending said ingredients by successively depositing each completed layered mound into a collector at the delivery end of the conveyor belt, and completely discharging each such blended ingredients thus deposited into the said collector into removable containers before the next completed mound is deposited in said collector.

4. The method of mounding and packaging a plurality of dry materials of different particle sizes which comprises depositing a predetermined weight of each of the said materialsin mounds of successive layer onto an intermittently movable conveyor belt, periodically moving the said belt between substantially equidistantly spaced loading stations for accumulating on the said belt predetermined weights of the materials comprising the said layered mounds, intermittently blending each of the completed layered mounds of material during delivery into a collector, and discharging all materials in each mound thus deposited into the said collector into a removable container before the next such completed and blended mound is deposited in .said collector.

5. The method of continuously forming uniformly composed mounds of a plurality of weighed dry ingredients with each ingredient in a separate layer, which comprises the steps of successively depositing increments of predetermined weight of each ingredient on an intermittently movable endless belt conveyor, said depositions being made at substantially equidistant spaced loading and Weighing stations along said conveyor, automatically controlling the feed of each ingredient deposited at its station by weighing through the belt of said conveyor at each station, and moving said conveyor to the next station upon completion of the said deposition, until each successive mound has received its proper weight of all ingredients in successive layers.

6. The method of continuously forming uniformly composed mounds of a plurality of dry weighed ingredients with each ingredient in a separate layer which comprises the steps of successively depositing increments of predetermined weight of each ingredient on an intermittently movable endless belt conveyor, said depositions being made at substantially equidistant spaced loading and weighing stations along said conveyor, automatically controlling the weight of each ingredient deposited at'its station by weigh ing through the belt of said conveyor, moving said conveyor to the next station upon comple- 13 tion of the said deposition, until each successive mound has received its proper weight of all ingredients, blending the ingredients of each mound, separately and during delivery from the delivery end of said conveyor to a collector and packaging each completed and blended mound delivered to said collector.

7. Gravimetric loading apparatus of the character described comprising a conveyor mounted for movement to and beyond a loading station, a feeder at said station for feeding dry material to said conveyor, means for operating the conveyor, means for operating the feeder, means for controlling said conveyor and feeder-operating means to move the conveyor to said station, halt the conveyor, operate the feeder to feed material to the stationary conveyor, and weight responsive means immediately below said feeder and conveyor to halt operation of the feeder when a predetermined weight of material has been fed to the conveyor.

8. Gravimetric loading apparatus of the character described comprising a conveyor mounted for intermittent movement to and past a plurality of spaced feeding stations, a feeder at each station for feeding dry material to said conveyor, means for operating the conveyor, means for operating each feeder, and means for controlling said conveyor and feeder-operating means to move the conveyor in increments each equal to the spacing between stations, to halt the conveyor at the end of each increment of movement, to operate each feeder to feed material to the conveyor during each interval between movements thereof, and weight responsive means immediately below said feeder and conveyor to halt operation of each feeder when a predetermined weight of material has been fed to the conveyor.

9. Gravimetric loading apparatus of the character described comprising an endless conveyor;

a plurality of feeders located at an equal number of feeding stations spaced at equal intervals along said conveyor, an electric motor for operating said conveyor, electrically operated means for independently operating each feeder, a motor circuit including manually operable means for closing the same; a feeder circuit for each feeder, means operated by the conveyor for automatically opening the motor circuit and closing the feeder circuits when the conveyor has travelled a distance equal to the spacing between stations,

and weighing means responsive to the weight load for each feeding station for opening the feeder circuit thereof when a predetermined weight of material has been loaded at said station.

10. A gravimetric loading apparatus comprising a conveyor mounted for movement along a predetermined path, a plurality of shaker-type feeders located along said path at an equal number of feeding stations, electrically operated shaker means for shaking each feeder, a motor for operating said conveyor; a motor circuit, a feeder circuit for each feeder, means including a normally open switch and a relay for closing the motor circuit and for maintaining it in closed condition, switch means operated by the conveyor for opening the motor circuit when the conveyor has moved a distance equal to the spacing between feeding stations, means also actuated by the conveyor for closing each feeder circuit when the motor circuit is opened and for maintaining said feeder circuit in closed condition, Weighing means for weighing the load on the conveyor at each feeding station, and means operated by each said weighing means for opening its feeder circuit when a predetermined weight of material has been fed to the conveyor at said station.

ROBERT L. MILLER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 21,169 McCreery Aug. 1, 1939 719,923 West Feb. 3, 1903 924,191 Scales June 8, 1909 924,940 Rough June 15, 1909 1,080,236 Saylor Dec. 2, 1913 1,203,285 Webber Oct. 31, 1916 1,300,274 Jeffries Apr. 15, 1919 1,724,403 Hutchinson Aug. 13, 1929 2,007,874 Redler July 9, 1935 2,198,788 Popov Apr. 30, 1940 2,285,765 Carswell June 9, 1942 2,549,704 Noble Apr. 17, 1951 FOREIGN PATENTS Number Country Date 434,501 Great Britain of 1935 529,272 Great Britain Nov. 18, 1940 566,651 Germany Dec. 20, 1932

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