US2366075A - Weighing and feeding device - Google Patents

Description

Dec. 26, 1944. Q s w Y 7 2,366,075

WEIGHING AND FEEDING DEVICE Original Filed June 14, 1957 8 Sheets-Sheet l W 29 6 INVENTOR.

CARL I Warn/v07- ATTORNEY,

1944- c. s. WEYANDT 2,366,075

WEIGHING AND FEEDING DEVICE Original Filed June 14, 1937 8 Sheets-Sheet 2 INVENTOR. 61421. J. WE. YA/YDT.

. ATTQRNEY.

Dec. 26, 1944.

c. s. WEYANDT WEIGHING AND FEEDING DEVICE Origifial Filed June 14, 1937 8 Sheets-Sheet 3 INV ENTOR. 6921. I. We Y/-7/YD7T Dec 26, 1944. c, WEYANDT 2,366,075

WEIGHING AND FEEDING DEVICE Original Filed June 14, 1957 8 Sheets-Sheet 6 INVENTOR. CARL S. \X/EYANDT BY pfma/y w Dec. 26, 1944. c. s. WEYANDT 2,366,075

WEIGHING AND FEEDING DEVICE Original Filed June 14, 1937 8 Sheets-Sheet '2' INVENTOR. CHRL 5. WE Y/P/YDZ' m g g Dec. 26," 1944.

6.8. WEYANDT WEIGHING AND FEEDING DEVICE Original Filed June 14, 1937 a Sheet -She et a INVENTOR. CARL .S. WEYfi/YDT.

Patented Dec. 26, 1944 2,366,075 WEIGHIN G AND FEEDING DEVICE Carl S. Weyandt, Homer City, Pa.

Continuation of appli cation Serial No. 148,070,

June 14, 1937. This application November 28, 1940, Serial No. 367,581

Claims.

The present invention relates to improvements in dry feeding machines for continuously or intermittently feeding or conveying materials at a controlled or uniform rate. The apparatus of the present invention is applicable to the conveying or feeding of various kinds of materials, uch as powder in dry orlumpy form, granular materials, articles, objects, and various kinds of bulk materials, and are particularly applicable to feeding fragile articles, such as crackers and the like, which are liable to be crushed or broken by the usual type of screw conveyors.

This application is a continuation of application Serial No. 148,070, filed June 14, 1937, for Weighing and feeding device. I

It is an object of the present invention to feed bulk or other materials in a steady continuous stream at a desired or predetermined constant rate without hunting.

A further object is the feeding of bulk material at a constant rate independent of variations in the consistency of the material being handled.

Another object is the provision of afeeding machine which is adjustable through a wide range to feed bulk materials at a constant rate.

Another object is the provision of a gravimetric feeding machine having switch means enclosed in a substantial vacuum to control the supply means thereto.

' Another object is the provision of a feeding machine of the gravimetric type having a snap action control to maintain a substantially constant level of material in the hopper.

Another object is the provision of an accurate bulk feeding machine that is dependable, simple in construction, and will operate over a long period of time without necessitating repairs or adjustments.

Another object is the provision of a feeding machine in which the rate of feed may be accurately and evenly adjusted at a substantially uniform or average rate so that violent fluctuations above or below the average rate of feed are avoided.

Another object is the provision of an apparatus to govern or control the operation of an electrically operated vibratory conveyor to feed material at a substantially uniform rate, which will not be affected by variation in supply voltage.

A further object is the provision of a bin or hopper having material fed thereto in which the feed to the bin or hopper is controlled to provide a predetermined maximum and minimum level of material in the bin or hopper.

A further object is the provision of a feeding machine comprising a hopper and an electrically operated vibratory feeder which is controlled to maintain a predetermined maximum and minimum level of material in the hopper, the material being fed from the hopper by a vibratory conveyor onto a discharging receiver.

According to the present invention, there is provided an adjustable electrically controlled vibratory feeder or conveyor unit which discharges onto a controller unit having a continuously discharging receiver, and the rate of feed from the conveyor is regulated by the controller unit in accordance with the instantaneous differential between the rate of feed to and rate of discharge from the discharging receiver. The controlled conveyor preferably comprises a vibratory conveyor mounted to have a free or natural period of vibration and actuated by electromagnetic impulses developed by a pulsating or alternating current. I prefer to employ a pulsating current obtained by interposing a static rectifier of any suitable type in an alternating current circuit of suitable frequency, and the vibratory conveyor is preferably mounted so as to have a free or natural period of vibration sub-synchronous to the recurrence period of the current pulsations, as this causes the amplitude of vibration of the vibratory conveyor to follow substantially instantaneously any variations in the pulsating current, and renders the vibratory conveyor stable to changes in load thereon. The pulsating current may be varied by changing the impedance of the controlled conveyor circuit by means of the controller unit.

The discharging receiver is mounted on one side of a balance of any suitable construction, and movement of the balance beam operates electrical means to control the operation of the controlled conveyor. The preferred electrical means is a switch having vacuum enclosed contacts. I prefer to employ an indicating balance which merely indicates when the two sides of the balance beam are balanced or unbalanced, and in the preferred modification the discharging receiver and its operating. mechanism are all mounted on one side of the balance, the unloaded scale being in a condition of balance. With this construction, the rate of feed of the discharging receiver may be set or predetermined by the addition of counterbalancing weights. The discharging receiver preferably is a belt or other type of continuous conveyor driven by a constant speed motor. If desired, an electromagnetically operated vibratory conveyor may be used on the an! controller member, and by means of a voltage regulator a constant current supply thereto is maintained to keep the vibratory conveyor operating at a uniform rate.

The controlled conveyor is supplied with material from a hopper or other suitable source and the controlled conveyor preferably is positioned adjacent the mouth of the hopper so that the accumulation of material on the conveyor retards or regulates the flow of material so as to constitute a vibratory gate which helps to maintain a uniform feed and assists in preventing clogging of the hopper discharge. The gate opening may be controlled by varying the opening between the hopper and conveyor, either by raising, lowering or tilting the hopper, or by raising, lowering or tilting the conveyor. The hopper preferably is vibrated by an inertia type of vibrator, the vibratory force being adjusted in accordance with the nature of material in the hopper to insure a proper fiow of material out of the hopper. The hopper, the controlled vibratory conveyor, and the controller member are all insulated from each other so that the vibration of one of them will not affect the vibration of any other one of them. The same alternating current source may be used for operating the controlled conveyor, the controller conveyor, and hopper vibrator.

The apparatus hereinabove described may be employed in conjunction with a vibratory conveyor which feeds material to the hopper and which is controlled to maintain a predetermined maximum and minimum level of material in the hopper, or the hopper control mechanism may be employed alone without the discharging receiver hereinabove described.

The above and other objects of the invention will be apparent from a consideration of the following specification taken in connection with the accompanying drawings which illustrate a preferred embodiment of the invention by way of example, and whereinz Figure 1 is a perspective view showing a preferred form of my invention;

Figure 2 is an end view of Figure 1 as viewed from the left;

Figure 3 is a side View of Figure 1;

Figure 4 is a fragmentary side view showing certain portions of the reciprocatory motor;

Figure 5 is a view of Figure 4 looking in the direction of the arrow V;

Figure 6 is an end view of Figure 4 looking in the direction of the arrow VI;

Figure '7 is an enlarged view of a vibration insulator;

Figure 8 shows a detail of an adjustment for the hopper;

Figure 9 is an enlarged view of a detail;

Figure 10 is a cross section view taken on line X-X of Figure 9;

Figure 11 is a wiring diagram illustrating the operation of the invention, certain parts being schematically shown; v

Figure 12 is a side elevation partly diagrammatic of a further modification of the invention;

Figure 13 is an end view of Figure 12;

- Figure 14 is a side view in section of a re cording device; Figure 15 is a front view of Figure 14;

Figure 16 is a partly diagrammatic view of a modification of the invention employing a hopper level controlled member;

Figure 17 is a view partly in section of a control member mounted on a hopper,

Figure 18 is a partly diagrammatic view of the control member and operating circuit for the modification shown in Figure 16, and

Figure 19 is a view similar to Figure 12 of a modification.

Referring to Figures 1, 2 and 3 of the drawings there is provided a balance or scale designated generally by the numeral 1 which has the bars 4 underneath secured to the bands 4 passing over the scale. Vibration absorbers or dampeners 2 are secured to the bars 4 at their upper ends and are secured at their bottoms to base 3. The scale i may be of any conventional type, preferably equipped with an adjustable dash pot for preventing violent fluctuations, one preferred type being more or less schematically shown in the drawings. The bearing brackets 5 (Figures 2 and 3) support knife edge bearings enclosed in cover 6 and on which is pivoted the scale frame or beam 1. The scale beam has a pan 8 pivotally mounted and vertically guided in known manner at one end adapted to receive counterbalancing weights shown in dot and dash lines covered by the cover 9, and the Pan III at the other end of the beam which is likewise pivotally mounted and vertically guided carries a conveyor mechanism designated generally by the numeral [5.

The base 3 has long slots ll (Figure 3) formed therein and the bolts 12 passing through the vibration absorbers 2 are threaded into blocks [3 on the under side of the base. By loosening bolts I2 the balance may be moved longitudinally and secured in such position for a purpose which will be hereinafter described.

The frame of the conveyor mechanism comprises angle bars l6 and H (Figures 1 and 3) rigidly secured together by cross bars [8 and I9 welded thereto to provide a rigid construction. At their ends the angle bars have pairs of bearing members 2| and 22 in which are journalled the front and rear conveyor shafts 23- and 24 respectively, and to which are secured the front and rear conveyor drums 25 and '28 having a flexible endless conveyor belt 30 passing thereover.

. A vertical plate 3| (Figure 2) is suitably secured to the angle bar l6 adjacent one end thereof and carries a constant speed motor 32 of any suitable type. I employ a synchronous rotary motor, or an induction motor operating at a constant voltage. Suitable reduction gearing built into the motor case drives a right angle shaft 33 coupled by a suitable coupling to the rear conveyor shaft 24 whereby the conveyor belt 30 is driven at uniform speed. The conveyor belt 30 may be made of any suitable material, and I prefer to use a varnished silk or cambric for this purpose. To

maintain the conveyor belt 30 sufficiently taut I provide a belt tightening roller 35 journalled.

at its ends in bars 36 which are adjustably secured to the angle bars [6 and I! in any suitable manner, as by bolts and thumb screws 31.

A plate 38 bolted or otherwise secured to the flange 39,.of the scale pan III has the angle bar [6 bolted thereto at its upper end whereby the conveyor frame is secured to the scale pan, and the outer side of the conveyor frame is supported by slotted upright rods 4| secured thereto by thumbscrews 42 and bolted to the bars I! secured to the bottom of the scale pan. This allows the conveyor belt to be removed without removing the conveyor frame from the scale. From the description so far pursued it will be apparent that the conveyor comprising a frame, endless belt passing over rollers and a constant speed electric driving motor therefor is carried on one pan of the scale beam and is partly counterbalanced by weights placed on the other pan of the scale beam.

A connection box 45 is secured to the plate 3i and the lead wires for the motor are secured to terminals in this box. In order to provide free movement of the motor 32 the wires 46 leading to the conection box are loosely coiled and pass through a suitable conduit 41 secured in any convenient manner along the scale case and termihating in a connection box 48 secured to the base of the scale. An adjustment beam 50 is secured to thescale I in any suitable manner and carries a weight I which is adjustable from one end of the beam to the other to provide a more delicate balance of the scale. A housing 52 suitably supported on the base 1 covers the indicator or pointer 55 which cooperates with a scale 54 to show when the scale is balanced or unbalanced.

Material is fed to the conveyor belt 30 by'a vibratory conveyor or feeder trough 60 mounted on a base BI and receiving material from a hopper 62 mounted on the frame 63, built up of angle irons. The bottom angle irons of frame 63 are flanged inwardly and have four posts 64 rigidly secured thereto and which carry vibration elements 65 at their upper ends and the base 6I of the feeder trough is supported on the posts 64 on the vibration elements.

The vibration elements 65 (Figure 7) are identical in construction with the vibration absorbers 2 except for length, and each comprises an in.- verted channel strip 66 with a hole 67 bored or punched therethrough, and having rubber pads 68 and 69 vulcanized or otherwise secured thereto by one of their faces respectively. To the opposite faces of the rubber pads are secured angle plates 'FI and 72 having holes I3 formed therein by which the vibration elements may be bolted to the posts 64. The vibration elements thus each comprise a pair of tension members 68 and 69 supported atone end and carrying the channel strip or supporting member 66 at their ends. The vibration elements are commercially available in strips of considerable length and the period of vibration of the vibration elements 65 for a given condition may be selected by suitable selection of the length of strip employed.

The electromagnet assembly of the motor for vibrating the conveyor or feeder trough 60 comprises a core "I4 (Figures 5, 4 and 6) in the shape of an E built up of laminated soft iron plates located between two angle bars I5 and I6, and rivets I1 pass through the bars I5 and I6 and through the plates of magnet core 14 to hold them in assembled relation. Two brackets or plates I8 and 19 having the reenforcing flanges 80 thereon are formed integral with the base 8| and the magnet core 14 is secured to the plates I8 and I9 in spaced relation thereto by bolts 8| passing through the angl bars I5 and I6 and threaded :into these brackets, a spacing plate 82 being interposed therebetween. A coil 83 of wire surrounds the middle leg of the magnet core and is secured in position by suitable clips 84 passing through the angle plates 85 which may be welded or otherwise secured to angle bars I5 and 16, a resilient pad 86 of rubber or other suitabl material being interposed between the coil and magnet base.

At the ends of the electromagnet two hexagonal side bars 81 and 88 of non-magnet material, such as, non-magnetic stainless steel, are bolted to the brackets I8 and I9 by nuts 89 threaded on to the reduced lower ends of the bars. The up per ends of bars 81 and 88 are reduced and threaded to receive adjusting nuts 90 and SI thereon,.and the spring supports 92 and 93 have holes therein through which pass the reduced threaded ends of the side bars. The spring support 92 is adjustably held in position on nut 90 by lock nut 94, and the support 93 is held on nut 9| by lock nut 95.

The spring holders 92 and 93 are bifurcated as indicated at 96 and 9'! and receive the prongs 99 and I00 of the spring 98 which is bifurcated at its ends. The spring 98 is shown as a laminated leaf or bar spring, but it may have any other suitable form, and may be composed of as many laminations as desired-to give it the required stiffness or flexibility and strength. It will be observed that the ends of spring 98 are loosely supported in the spring holders 9I and 92 so that the ends are free to move axially in the spring supports when the spring flexes.

The armatur assembly comprises a bar IOI built up of laminated plates which are held in assembled relation between the angle plates I02 and I03 by means of rivets I04 passing therethrough. A motion transmitting or connector member I05 is secured to the angle plates I02 and I03 in spaced relation to the armature bar IOI in any suitable manner, as by welding thereto, and the assembly comprising the armature IOI, angle plates I02 and I03, and motion transmitting member I05 are secured to the spring 98 by a recessed clamp bar I06 and bolts I07 passing through the clamp bar and threaded into the motion transmitting member I05 and angle plates I02 and I03.

In the preferred form shown, the motion transmitting member I05 is angle shaped and is bolted to a plate IIO welded to the bottom adjacent the bratory motion.

open end III of conveyor trough 60. The opposite closed end II2 of the conveyor trough has a bracket H4 welded or otherwise secured thereon to which is suitably bolted one end of a leaf spring II5, the other end of the spring being suitably bolted to a bracket II6 which may be integral with the base 6|. The spring II5 supports and guides the rear end of the conveyor trough and the front end is supported and guided by the spring 98 so that it will be capable of vi- I prefer to have spring II5 stiffer than spring 98, and by interposing plates of suitable thickness between the bracket I I6 and spring I I5, the initial flexing or biasing of springs 98 and I I5 may be adjusted. It will be understood that the rear end of the trough may be mounted for vibratory movement in any other suitable manner. The spring holders 92 and 93 are movable longitudinally along the side bars 87 and 88 by adjustment of nuts 90, SI, 94 and 95 and it will be seen that when the spring holders are adjusted downward it tends to unbias spring 98 and moves the armature IOI toward the electromagnet I4 to reduce the air gap therebetween. This adjustment decreases the natural period of vibration of the conveyor trough.

The electromagnet I4 is actuated preferably by a pulsating current obtained through a rectifier of any suitable type supplied with alternating current from any suitable source, and forces the armature IOI and trough 60 secured thereto to vibrate at a forced frequency the same as the frequency of the current impulses. I prefer to adjust or select the spring members for the trough sothat the trough has a free or natural frequency of vibration less than the frequency of the current impulses. This may be accomplished by adjusting the spring bias or by changing the number of leaves in sprin 98 or II or their dimensions to preselect the natural period of vibration. After the conveyor mounting has been adjusted to the desired natural period the air gap may be adjusted by changing plate 32 to one of suitable thickness, a thinner plate increasing the air gap, and a thicker one decreasing the air gap. I prefer to mount the conveyor trough 60 so as to have a frequency of free vibration of about to /12 of the frequency of the pulsating current. It also will be'observed that the trough 5G and the material therein being moved are above the spring and motor so that when material is added to the trough the tendency of this increased weight is to deflect the spring 98 toward the electromagnet and decrease the air gap and increase the natural period, and if th air gap is originally selected to allow for such deflection without having the armature strike the electromagnet, the amplitude of vibration of the trough will be increased. However, the adjustment preferably is such that the natural period of vibration is not allowed to reach the state of synchronism with the current pulsations. The vibration members 65, which preferably follow a pseudo-harmonic law of vibration, are adjusted orselected preferably to have a period of vibration substantially the same as the natural period of the conveyor springs.

The vibratory trough 80 feeds material onto the uniformly moving belt conveyor 30, which discharges the material at its outer end. A brush Iii bolted to a metal brace H8 is adjustably secured by arms III! to the frame members I5 and ii and removes all material that may tend to adhere to the conveyor belt. This brush is disposed at an angle so that material will not accumulate thereon.

The frame 63 has two pairs of side members I211 and I2I which have cross pieces I22 at their upper ends, and have the angle plates I23 adjustably secured thereto. The hopper brackets I24 are secured to the plates I23 and comprise an inverted L-shaped foot which is bolted to the plates I23 at the top by bolts I25 and at the sides by bolt I25. The upright part of the hopper bracket I24 is bifurcated to form spaced bars I28 and I28 between which is welded or otherwise secured the inclined internally threaded sleeve I30. I32 are rotatably journalled on bolts I33 and I34 passing through suitable transverse holes in the upper ends of bars I28 and I29, and cables I35 and I35 are secured to the respective pulleys at one end thereof by suitable clamps, the other ends thereof being clamped to the wall of conical hopper 52. Adjustment screws I38 and I39 are threaded through threaded sleeves I30 with their ends abutting one segmental face of the pulleys I3I and I32 respectively. The other ends of screws I38 and I39 carry hand wheels I40 and MI. It will be apparent that the hopper 62 is supported by the cables I35 and I36 secured to the frame, and the frame rests on-vibration absorbers I31 which are constructed in the same manner as the vibration elements 65.except that they are of such length as to act as vibration dampeners to prevent the transmission of vibration from the frame 63 to the base 3.

The smaller end of the hopper is spaced from the bottom of conveyorGIl and by rotating pulleys I3I and l32 the hopper may be raised or lowered with respect to the conveyor bottom. The space I between the end I46 of the hopper and the bottom of conveyor constitutes Segmental grooved pulleys I3I and a controllable feed opening, which may be varied by varying the height of the hopper with respect to the conveyor bottom. The ends of the bars I28 and I29 may be pointed to cooperate with suitable graduations I41 on the pulleys to insure correct adjustment thereof. Material is introduced into the hopper 62 at its larger end I48 and is discharged from the hopper onto the conveyor trough 50 through the feed opening I45, the conveyor acting as a vibratory gate and the reciprocations of the. conveyor chute carries the material along and discharges it from the open end thereof onto the moving conveyor belt 30.

A block I50 secured to the hopper has a bore therein in which is secured one end of bar I5I by a set screw I52, the other end being adjustably secured in a block I53. A clevis bracket I54 is welded or otherwise secured to the cross piece I55 of the frame 53. The adjustment handle I55 is in the form of a U and a bolt I51 passing through the base of the U and through the clevis bracket I54 serves as a pivot for the handle I55. A rubber grommet I58 is located on a. bolt I59 passing through the arms of the U handle l56, and one end of a rod ISO is looped over the grommet I58, the other end being adjustably secured in. block I53. A nut on the end of bolt I51 clamps the handle I55 in adjusted position. By means of this construction, by pivoting the handle I56 about its axis I51 the hopper may be tilted from the vertical as desired to adjust the feed opening I45 from the end or from the top surface of conveyor 60. The clevis bracket I54 is calibrated, and theindex mark on the handle I56 cooperates therewith to insure correct setting of the hopper. The hopper also may be adjusted by adjustment of rods I5I and ISO in. block I53.

From the foregoing description it will be apparent that the hopper 52 is substantially insulated from the frame 63 so as to practically prevent the transmission of vibration between the hopper and frame. The rubber grommet I58 prevents the transmission of vibration through rods I5I and I60 to the frame 63, and the cables I35 and I35 prevent the transmission of vibration to the hopper supports and thence to the frame. The vibration absorbers I31 prevent the transmission of vibration from frame 53 to the base 3, and the vibration absorbers 2 prevent transmission of vibrations to or from the balance I or base 3.

To overcome any tendency of the material in the hopper to form a bridge or clog the hopper, I provide a vibrator designated generally by the numeral IBI described in detail in my copending application for Vibratory electrical apparatus and methods, filed October 21, 1936, Serial No. 106,851, of which the present application is in part a continuation. Briefly, the vibrator I5I comprises an electromagnet on a base I52 adapted to be secured to the hopper 82 and having two vibratory members secured to the base I52 and supporting an armature for vibratory movement. The vibrator I5I preferably is operated by a pulsating current selected by a static rectifier from a source of alternating current, the

free period of vibration of the armature and resilient members being selected or adjusted to be sub-synchronous, and in some cases synchronous with the recurrent period of the current impulses. However, it will be understood that if desired the vibrator I6I may be operated by alternating current with the free period of vibration of the armature and resilient elements there of in synchronism with the electromagnetic impulses developed thereby.

A switch operating bar I15 is secured to the one side of the scale beam 1 by angle brackets I16 and I11 and carries the contact screws I18 and I19 which are preferably substantially equidistant from the knife edge bearing 6 and are located as near thereto as practicable. By 10- cating the switch contact screws I 18 and I19 closer to the pivot than scale pan I0 a lever advantage is obtained. The contact screws are threaded through suitable holes in the bar I and can be locked in adjusted position by the lock nuts I8I and I82. 7 The control switches are located in the switch boxes I83 and I84 suitably secured on the base of balance I on an angle plate I85, and as these switch boxes and contained switches are alike in construction, only one will be described in detail.

Referring to Figures 2 and 11, the switch box I83 contains a switch I81 of any suitable type and preferably of the vacuum type which requires only a small movement on the order of a few thousandths of an inch to make or break the circuit, and can be operated by a change of a fraction of an ounce on the scale pan. The switch-shown schematicall in Figure 11 comprises a vacuum cylinder I88 permanently closed at one end and closed at the other end by a diaphragm I9I to which is secured in gastight relation a movable switch operating arm I92. The arm I92 has a contact element I93 at one end which extends to the fixed contact or lead I94 secured to the back fixed wall of the switch cylinder. The cylinder I88 is secured to the box I83 by a clip I91 or in any other suitable man ner. A spring I99 is secured at one end to the box I83 and at its other end carries a hook 20I. A second spring 202 is secured to the samesupport as the spring I99 and has its end 203 bearing against arm I92 so that the arm normally is held in contact with the hook 20I. In unbalanced position the contact screw I18 bears against the spring I99 and upon downward movement of the scale beam 1 on the left the contact arm I92 will break contact with lead I 94. For convenience of reference the limit switch in box I84 is given the numeral 205 and its contact arm is designated by the numeral 206 operated by hook 204 and springs 209 and 208, and the fixed contact thereof is designated by the numeral 201. In balancedposition there is no contact between the adjusting screws I 18 and I19 and the springs 203 and I99.

The electrical control system, excluding the limit switches I81 and 205 just described aremounted on a panel enclosed in the control box 2I0 which is supported from the base on the uprights 2H, or in any other suitable manner. Referring to Figure 11, wherein the electrical control system is diagrammatically shown, there are two thermionic valves 2I5 and 2I6 employed as rectifiers, the filaments 2I1 and 2I8 of which are heated from the secondary coils 2I9 and 22I of transformer 222, which obtains its power from any suitable alternating current source connected to wires 223 and 224. The thermionic valves and 2I6 have anodes 225 and 226 respectively. One half wave from the alternating current source passes from wire 223 through lead 225 and switch 226 to lead 221, and from thence through the coil 220 of the hopper vibrator I6I and hopper vibrator motor rheostat 229 to the cathode 2I8 thenc to anode 226 and by wires free rounded 23I and 232 to wire 224. The other half wave passes from wire 224, and leads 232 and 233 to the cathode 2I1 thence to anode 225 and to the normal feed current regulator comprising rheostat 234 and vernier rheostat 235 in parallel therewith, and by lead wires 236, 231 and 238 to the terminal I 94 of the overfeed switch I 81 and thence when switch I81 is closed and switch 205 open, through switch arm I92 and lead wires 239 and 24I to th coil 242 of the vibratory conveyor motor, and thence by lead 221, switch 226 and lead 225 to the wire 223. When the scale is in balanced position, switch I81 is closed and switch 205 is open. Switch I81 remains closed when the scale is balanced and when the feed is too slow, and opens when the feed becomes too heavy.

The normal feed rheostat 234 and. normal feed Vernier 235 are also connected by wires 238 and 243 to terminal 244 of switch 248, this switch being left open when adjusting the apparatus, as will hereinafter appear. Terminal 254 of the switch 248 is connected by wire 253 to overfeed resistor 252, which is connected by lead wire 25I to common return wire 24I. When switches I81 and 248 are closed the resistance of switch I81 is low enough so that the current flows from wire 238 through switch I81 and by wire 239 to return wire 24I, and no appreciable current flows across terminals 244, 254 of switch 248, but when switch I81 is opened the resistance 252 is thrown into series connection with the normal and vernier rheostats 234, 235 and cuts down the current supplied to the motor 242 through the path provided by normal feed rheostat 234 and Vernier rheostat 235 and by wires 238 and 243 to switch 248 and thence across the terminals 244, 254 of switch 248 and by wire 253 to resistor 252, and thence by wire 25i to common return 24I.

The underfeed rheostat 245 is connected by Wire 246 to terminal 241 of switch 248. The other terminal 258 is connected by wire 251 to switch element 201 of switch 205. and when switch 205 is closed, the circuit is completed through switch rod 206, and wires 256 and 255 to the common return 24I. sistor 252 is in series with the normal feed resistor when switch I81 is open, and. is not effective when switch I81 is closed, while underfeed resistor 245 is in parallel with the normal feed resistor when switch 205 is closed, but is not effective when switch 205 is open. Resistor 245 preferably is very high relative to normal feed resistor 234, and resistor 252 preferably is very low relative to normal feed resistor 234. This arrangement cuts down the current supply to the motor 242 when the overfeed resistor 252 is cut in, and increases the current when underfeed resistor 245 is cut in. The rheostats 234, 235, 229, 245 and 252 are so connected that the full resistance may be obtained without opening the circuit, thereby insuring that they are not accidentally completely out out of the circuit at any time. The belt conveyor motor 32 is connected by lead wire 26I to the one alternating current supply wire 224, and b wire 282, switch Thus, it will be seen overfeed re-,

I99 and hook 20I, thus permitting spring 202 to press rod I82 downwardly and open the circuit between contact points I94 and I93. Similarly, switch 205 is adjusted so that contacts 201 and 2% make contact when the scale beam moves downward on the right corresponding to underfeed.

To start the operation of the feeder the switch is closed to supply alternating current to the belt conveyor motor 32 which drives the belt conveyor mounted on one pan of the scale. The conveyor 32) is thus driven at a uniform rate by the synchronous motor 32 in Figure l. Sufficient weights now are added to the right scale pa S to partly counterbalance the weight of the left scale pan comprising the discharging receiver and actuating mechanism thereof, and by moving the weight 5i on adjustment beam 50 the desired state of unbalance is accurately obtained. Or, where small quantities are to be fed, the sliding weight 5! alone may be adjusted to obtain the desired rate of feed, without addition of weights. The switch 248 is left open and switch now is moved to closed position. This energizes the hopper vibrator motor and the conveyor motor 242 and causes material to be moved along the conveyor trough S0 and onto the continuously moving conveyor 30, the hopper vibrator is; preventing the material from clogging the hopper. While the material is thus being fed from the hopper 82 onto the reciprocatory conveyor 58, and thence onto the uniformly moving belt conveyor 30, the normal feed rheostats and 235 are manually adjusted to vary the discharge of material from conveyor 60 onto the conveyor Sil at the desired or predetermined rate so as to bring the scale into substantial balance. The Vernier rheostat 235 offers a fine adjustment in parallel with rheostat 234 whereby a very delicate adjustment is obtained of the pulsating current supplied to the motor or controlled conveyor 80, and because of the subsynchronous relation of the natural period of vibration of the conveyor motor to the recurrence period of the pulsating current the amplitude of vibration of the motor operating the conveyor can be accurately adjusted by adjusting the current to control the rate of feed therefrom. Should the feed from the controlled conveyor be too fast, that is, an overfeed, the left scale pan descends and spring 202 engages switch arm I92 to open the switch I81 and stop the reciprocatory conveyor motor without however affecting the hopper vibrator motor or the belt conveyor. If this happens the vemier rheostat 235 then is adjusted to reduce the current supply to the vibratory conveyor until the material is fed therefrom onto the belt conveyor 30 so as to bring the scale beam into balanced position. As only overfeeding causes the switch I81 to open, it will be seen that at this stage of operation the controlled conveyor shuts off only when there is an overfeed, so that the balancing operation is not difficult to accomplish. It is only necessary to adjust the rheostats 234 and 235 to secure continuous operation of the vibratory conveyor without overfeeding ,and consequent unbalancing of the scale beam.

If des red, the apparatus may be operated with-- out closing switch 248 in which case the apparatus has only an overfeed limiting control. By setting the controlled conveyor to feed at a rapid rate it will deposit batches of material on the controlled conveyor separated by blank areas, these batches being continuously discharged at given intervals of time from the controller conveyor.

The rate of discharge of the conveyor 30 is determined by its eifective length, its lineal speed and the noncounterba-lanced weight on the right. For example, if the perimeter of driving roller 26 is selected to be one foot, the speed of the drive'shaft 33 of the synchronous motor 32 is selected at six revolutions per minute and the effective length of the conveyor belt is two feet, the rate of feed will be one-half the speed of the motor times the noncounterbalanced weight. That is, the rate of feed is determined by the formula:

Unbalanced weight times one revolution of motor per minute times the circumference of drive roller divided by length of the conveyor belt.

In order to accurately gauge the length of the conveyor belt proper allowance should be made for the different angles of repose of different materials. This adjustment is made by moving the receiver toward or away from the end of the controlled conveyor to set the effective length of conveyor belt 30 as desired, by loosening bolts I2, shifting the scale longitudinally, and then tightening the bolts.

If automatic underfeed as well as overfeed limiting control is desired the switch 248 is now turned to closed position for automatic operation. In closed position of the switch 248 with the scale balanced, switch I81 is closed and switch 205 is open. A underfeed of material causes the switch elements 206 and 201 to contact while switch I81 remains closed and thus resistor 245 is placed in parallel with resistors 234 and 235 whereby an increased current is supplied to the motor coil 242 which speeds up the feed from the conveyor trough 60 until the point of balance is reached. When balance is reached, contacts 206, 201 are opened, while switch I81 remains closed to thereby restore the normal feed current. If an overfeed occurs the left side moves down thereby opening switch I81 while switch 205 remains open, which places overfeed resistor 252 in series with the normal feed resistors 234, 235 which cuts down the current and slows down the rate of feed from trough until balance is again restored, whereupon switch I81 again closes, while switch 205 remains open. The above described mode of operation takes place as long as current is supplied to the apparatus.

In the structure partly diagrammatically shown in Figures 12 and 13, and wherein like reference characters refer to like parts, the balonce I is mounted on two L-shaped bars 225a and 22611 placed transversely across the supporting frame 221a built up of angle iron, and has two vibration absorbers 223a. secured thereto in any suitable manner. The vibration absorbers 223a comprise an angle bar 223a secured to a rubber pad 23Ia which in turn is secured to a bar 232a secured to the scale base. The frame 221a is suitably secured to the angle iron frame 235a which carries the hopper 62, and the conveyor base GI is directly mounted through vibration members 55 on the bottom bars of the frame 235a.

The scale pan I0 has an inverted U frame 231a secured thereto by means of a, retaining plate 238a and bolts 239a. The arms of the frame 231a extend below the scale base and have welded thereto the transverse bars 240a and In, having arms of unequal length. One arm 24241 of each is bolted directly to the conveyor frame bar l6, while the other end 244a has slotted extensions 246a and 241a secured thereto by bolts and thumb screws 249a. and are similarly secured at their lower ends to the conveyor frame bar IT by bolts and set screws m. The U-frame 237a is adjustably secured to scale pan ID by plate 238a so that the conveyor structure can be positioned so that the center of gravity is directly beneath the support and thereby eliminate bind on the scale. Thesynchronous motor 32 is carried by the conveyor frame IS in any suitable manner and drives the drive roller 26 or the conveyor belt 30. This modification in which the discharging receiver is underslung, is of particular value in installations where there is limited head room. Furthermore, the frame 227a may be enclosed to protect the scale from dust and dirt, as when dusty materials are being handled, and a closure cylinder 255a is inserted in the conical hopper 62 to eliminate escape of dust therefrom.

In the structure shown in Figures 14 and 15, I have shown partly diagrammatically a recording device which records when the scale is in balance or out of balance, and the record of which may be used for calculating the total quantity of material dispensed by'the feeder. Referring to the drawings, the housing 52 of the scale has a spring clock or electric clock 260 secured thereto in any suitable manner and a chart plate 266 is secured to the shaft 262' and is driven by the clock at a uniform speed. A cir' cular chart 233 having a central perforation therethrough is secured to the chart plate 28V and clamped in position by a cap 264' in known manner. The chart 263' has a plurality of con centric circles marked thereon, which represent units of weight, as for example, ounces or fractions of an ounce, and preferably an intermediate circle indicated by' the numeral 265 represents balanced condition. An indicator or pointer 266 is secured to the scale in known manner and replaces theindicator 55. The indicator 266 may have its end portion 26'! bent over to act as a stylus, and the chart 263 may have a waxed or smoked surface so that the point 261 of stylus 266 scribes a line thereon as the chart is rotated by the clock. Or, if desired, a pen of known construction may be employed on the indicator 266 in connection with a paper chart. The inscription on the chart furnishes a visual indication of the operation of the feeder and produces a record from which the past performance of the feeder can be determined by visual inspection. By a suitable planimeter the chart can be integrated to calculate the total weight of material which the feeder machine dispenses.

In Figures 16 to 18 I have shown a structure of particular value in feeding materials which have a tendency to flush out of the hopper, of which materials finely divided activated carbon or fullers earth are examples. In this structure wherein like parts are designated by like reference characters, a conveyor trough 210 is provided to supply material to the hopper 62, and a control member 211 is provided to cut off the operation of the conveyor when the level of material in the hopper 62 reaches a predetermined height, and cut in the operation of the conveyor when the level of the material in the hopper falls below a predetermined level. In feeding materials which have a tendency to flush the hopper vibrator I6I is operated so as to pack the material in the hopper and retard or prevent flushing. The conveyor 2'10 is preferably of the electromagnetically operated'vibratory type, and preferably is operated by a pulsating current having substantial-zero intervals between impulses, and the natural periodicity of the conveyor being sub-synchronous to the recurrence periodicity of the current impulses.

Referring to the drawings, the control member 2' is mounted on the hopper 62 preferably at one of the nodes of vibration thereof, and comprises a diaphragm 212 of rubber or other suitable flexible material secured at its periphery to the hopper wall in dust proof relation by bolts 213 and a spacer ring 214. The control member 2' comprises an abutment plate 215 secured in place by bolts 213 on which is secured an adjustable plate 216, by the screws 27! located at one end. The other end of plate 216 carries an adjustment screw 218 and lock nuts 219. A switch casing 28! of Bakelite or other suitable material is suitably secured to the adjustment, plate 276.

A U-shaped bracket 282 is secured to the base' at one end of the case 20! by a countersunk screw 203, the bracket being cut away to provide hearings or pivot edges 284 for the switch armature bar 285. An internally threaded metal bushing 286 expanded at its ends to form a rivet holds a retaining plate 281' in place, and the bracket 28! overlies the permanent hors shoe magnet 280 and has its end 209 upturned to form a stop for the end of armature bar 285. A screw 29i threaded into the retaining plate 281 abuts the bottom of the magnet 288 and holds it in place. A second threaded bushing 202 in the casing has a switch contact disk 293 threaded into the bushing and upset at its end whereby it is held in place, and on binding post 294 is threaded into the bushing 292, the other binding post 295 being threaded into the bushing 1286. A second switch contact member 290 is riveted to a flexible conductor strip 297 secured at its opposite end by the screw 29 i, and a bracket 298 held by the riveted contact 295 to the strip 29? has an aperture 299 therein which is engaged by a tongue 30| on the armature bar 285. At its opposite end the armature bar 285 carries an armature in th form of a soft iron knurled disk 302 threaded into the armature bar 285 so that it can be adjusted, and is held by a bent spring plate 303.

From the description so far pursued it will be seen that pivotal movement of th armature bar 285 in the outward direction carries with it the armature disk 302, and the hooked engagement of tongue 905 on armature bar 205 with the bracket 298 on strip 291 pulls the contact point 296 away from the contact 293 to open the switch. Contact 2% is connected. to binding post 294 by the bushing 292, and conductor strip 29! is connected to screw 29! threaded into conductor bracket 28'! which is connected to binding post 295 by bushing 2%. moves inward the armature disk 302 comes into the field of the permanent magnet 288 and the magnetic attraction at the end of the armature bar swings the bar with a snap action thus closing contact points 293 and 296 with a snap action.

A push button 305 has a spring 306 interposed between it and the end of switch bar 285, a knob 30'! being provided on the bar tolocate and hold the spring 306 in place. Th flexible diaphragm 212 has a bolt 308 secured thereon by nuts 309 and M0 and washers 3| I, the end 3M of the bolt passing through an aperture 3 l3 in the plate When the armature bar I 215. The head 314 is adapted to contact the push button 305 and is held in disengaged position therefrom by a spring 3l5 which abuts the plate 215 at one end.

The electrical diagram for operating the electromagnetically reciprocable motor of conveyor 219 is shown in Figure 18. A thermionic valve 3|! employed as a rectifier has the anode 3|8 and cathode M9, the cathode being heated from the secondary winding of a transformer 32 I, the primary winding of which is connected by the wires 322, 323 and switch 324 to the commercial power lines 325 and 326, or to any other source of current of suitable frequency. When the switch contact points 293, 298 of the control member 213 are in contact current pulsations separated by substantial periods of zero energy pass through the circuit comprising power line 326, lead wire 321, anode 3l8, cathode 3l9, and lead wire 328 to binding post 294, thence by bushing 292 and contact points 293 and 295 by the conductor strip 291 to the bracket 2231 and by bushing 286 to binding post 295, thence by wire 329 to the coil 330 of the electromagnet 33$ of the reciprocatory motor. of conveyor 210, thence by wire 332 through resistor 333 and by switch 335 and wire 336 to power line 325. An electrically operated bell 338 is connected across wires 336 and 329, and with switch 339 closed the bell will ring whenever the level or material in the hopper falls too low, and the conveyor 210 is started.

The operation of the apparatus now will be described. Referring to Figure 3, it is assumed that the mechanism there shown is operating automatically in accordance with the description of the wiring diagram in Figure 11 so that material is bein fed from the hopper 62 (Figure 16) onto the conveyor belt 30 to feed a predetermined constant weight from the conveyor belt. Referring to Figures 17 and 18, when the level of material in the hopper falls so low as to allow the diaphragm 212 to be expanded inwardly to the left by the spring 3l5, the end 3M of the rod 308 disengages the push button 305 of the switch 28!, and the release of the pressure of spring 309 on the armature bar 285 brings the armature 302 into the field of the permanent magnet 298,

whereupon the armature is attracted to bring the switch bar 285 into closed position, as shown in Figure 17. When this takes place switch contacts 293 and 296 make contact, and the pulsating current circuit from wire 328'is closed through binding post 294, bushing 292, switch contacts 293 and 296, conductor strip 291 and bracket 281, bushing 280 and binding post 295 to wire 329,

thence through the coil 330 of the electromagnet 33| of the conveyor 210, and thence by wire 332, resistance 333, switch 335, and wire 335 to the main wire 325. The circuit being thus completed the conveyor 210 is operated to feed material into the hopper 62. As the level of material in the hopper 62 builds up it exerts a greater pressure upon the diaphragm 212 and gradually pushes the diaphragm to the right against the action of spring 3l5 until the end 3 contacts the push button 305 and pushes this button toward the right. As the button 305 is pushed further and further toward the right the pressure of spring 305 on the end of armature bar 285 finally overcomes the attraction of the magnet 288 for the armature 302, and as soon as the armature 302 starts to move out of the field of the permanent magnet 288 the air gap becomes greater and the attraction therefor diminishes so that the armature moves with a snap action to its outermost position. The hooked engagement of the tongue 30! with the end 298 of the conductor strip 291 pulls the conductor strip suddenly to the right as shown in Figure 18 and opens the contact between switch contacts 293 and 296. This opens the electrical circuit and as the supply of pulsating current for the electromagnet 331 is cut off, the operation of the conveyor 210 ceases. As material is fed from the bottom of hopper 62 by the conveyor 50 the level of material in the hopper gradually falls and allows the diaphragm 212 to gradually move inwardly to the left, as seen in Figure 17. This also allows the end 314 of the post 308 to move to the left and gradually releases the pressure of the button 305 against spring 306 and gradually brings the armature bar 285 toward its inward position. As soon as the armature 302 comes within the field of the permanent magnet 288 it is suddenly attracted by a force which overcomes the residual pressure of the spring 308 so that the armature bar 285 is pulled to its innermost position with a snap action, thus closing switch contacts 293 and 295 with a snap action which starts operation of conveyor 210 to feed material to the hopper 62.

This structure, wherein the level of material in the hopper is maintained between predetermined maximum and minimum levels, results in a more uniform feeding action by the conveyor 60 to the belt 30 or other suitable device, due to a more uniform weight of material tending to force material out of the feed opening between the hopper and conveyor into the conveyor. This arrangement is of particular value in feeding materials, such as activated carbon of fine mesh which has a tendency to flow like a liquid unless maintained compacted under pressure. With the combination of the hopper vibrator in this arrangement to provide for the compacting, which, if desired, can be done manually, and the control of the level of material in the hopper so as to maintain a predetermined pressure, such material may be fed successfully in a uniform manner.

The provision of a snap action switch 28! for energizing and de-energizing the conveyor 210 is of particular importance where the hopper 52 is subject to vibration, as by the vibrator I61. Whereas an ordinary type of switch may have a tendency to fluctuate between on and off positions, due to the vibration of the hopper, the action of the magnetically snap acting switch herein described is so delicate that a considerable movement of the push button 305 is required to move it from on to off position and vice versa, and consequently in either open or closed position the vibration of the hopper wall alone is not sufilcient to open or close the switch. Although I prefer to, employ the hopper control system shown in Figures 17 and 18 in connection with the feeding mechanism shown in Figures 1 to 13, it will be understood that the mechanism may be employed alone in conjunction with filling bins or receptacles to a given levelandmaintain the level of material therein between maximum and minimum limits, or substantially constant. If desired, a signalling device, such as an electric bell or light may be provided to give an audible or visual signal when thematerial in the bin falls to or below a predetermined level.

In the modification shown in Figure 19, wherein like parts are indicated by like reference numerals, the belt conveyor is replaced by a vibratory conveyor 342 similar to conveyor 50 with a base 8! set on vibration absorbers 65 on a plate I secured to the scale pan l0. A voltage regu lator 343 maintains the conveyor 342 operating at a constant amplitude and material is supplied to the conveyor 342 by a vibratory conveyor 80 controlled by the scale.

As the invention may be embodied in other specific forms without departure from the spirit or essential characteristics thereof, the present preferred embodiment is therefore to be considered as illustrative rather than restrictive of the invention.

What is claimed and desired to be secured by United States Letters Patent is:

1. The combination comprising an electricall operated controlled conveyor, an electrical circuit including means for supplying a normal feed current to operate said conveyor, controller member located to receive material from said conveyor, an impedance, means operated by said controller member to place said impedance in series in said circuit to reduce the operating current of the controlled conveyor when the controller is over-weight, a second impedance, and means operated by said controller member to place said second impedance in parallel in said circuit to increase the operating current of the controlled conveyor when ,said controller member is underweight.

2. The combination comprising an electrically operated controlled conveyor, an electrical circuit including-means for supplying a normal feed current to operate said conveyor, a controller means located to receive material from the conveyor, a resistance, means operated by said controller means to place said resistance in series in said circuit to reduce the operating current of the controlled conveyor when the controller means is overweight, a second resistance, and means operated by said controller means to place said second resistance in parallel in said circuit to increase the operating current of the controlled conveyor when the controller means is underweight.

3. The combination comprising an electrically operated vibratory controlled conveyor, an electrical circuit providing a normal feed current to said conveyor, 3, balance for receiving material from said conveyor, impedance means operated by said balance to place said impedance means in series in said circuit to reduce the current to said conveyor when the balance is over-weight, and means operated by said balance to place said impedance means in parallel with said circuit to increase the current to said conveyor when the balance is underweight.

4, The combination comprising an electrically operated vibratory controlled conveyor, an electrical circuit providing a'normal feedcurrent to said conveyor, a balance, a continuously discharging conveyor on said balance receiving material from said vibratory conveyor, impedancemeans, operated by said balance to place said impedance means in series in said circuit to reduce the current to said vibratory conveyor when the balance is overweight, and means operated by said balance toplace said impedance means in parallel with said circuit to increase thelcurrent to said vibratory conveyor when the balance is underweight. v

5. In an apparatus 01 the character described, a balance, a continuously discharging conveyor on said balance, an' electrically operated controlled vibratory conveyor for feeding material to the discharging conveyor in a continuous stream, a source of alternating current, a rectifiersupplied from said alternating current source and passing current pulsations having substantial time intervals between pulsations, means actuated by the current pulsations for actuating the vibratory conveyor, vacuum enclosed switch means operated by said balance, and means operated by said vacuum switch means to control the feed of the vibratory conveyor to maintain a substantially uniform weight of material on said discharging the vibratory conveyor, and means actuated by a change of the weight of material on the discharge conveyor to control the feeding means through regulation of the vibratory conveyor and reduce the lag of correction inothe discharge feed, resulting in a'more uniform rate of discharge of material from the device.

7. In a device for feeding materials at a selected rate periunit of time, the combination of a hop per, a weighing device, a, constant rate discharge conveyor on. the weighing device, a vibratory conveyor cooperating with the hopper to receive and control the flow of material from the hopper to the discharge conveyor, the head pressure of the material in the hopper effective on the vibratory conveyor determiningthe uniformity of the flow of material to the discharge conveyor, means actuated by a change of the weight of material on the discharge conveyor for automatically governing the rate of flow of material from the .vibratory conveyor tothe discharge conveyor to regulate the weight of, material on the latter, means for feeding material to the hopper, and means for operating the feeding-means and maintaining a predetermined head pressure of material eflective on the vibratory conveyor to provide uniform flow at the regulated rate and'thereby reduce the lag of correction in the discharge feed, resulting in a more uniform rate of discharge of material from the device.

8.. In apparatus of the character described, a

-- weighing device, a continuously discharging conveyor on said weighing device, a controlled vibratory conveyor arranged to produce a substantially constant selected feed of material to said discharging conveyor, means actuated by pulsations for operating the vibratory conveyor, means operated upon the movement of the weighing device when underloaded to increase the amplitude of the pulsations to the vibratory conveyor and produce an overfeed greater than said selected feed, and means operated upon movement of the weighing device when overloaded to decrease the amplitude of the pulsations to the vibratoryconveyor and produce an underfeed less than said selected feed, the over and underfeecycontrol of i the vibratory conveyor establishing" an average delivery of material approximately equal to said selected feed by the continuous conveyor.

- 9. The structure of claim 8 characterized in that the continuously discharging conveyor is vibrated to distribute longitudinally over the surface of said conveyor the overfeed andunderfeed amounts of material to reduce the lag in the correction of the feed thereto and to provide a un1 form discharge of material from the continuously discharging conveyor.

10. In apparatus of the character described, a controlled vibratory conveyor, a unidirectional pulsating current circuit supplied from an alternating current source and passing substantially spaced current pulsations for operating said vibratory conveyor, means for regulating the current pulsations to supply a selected normal feed current to the vibratory conveyor, a controller member carrying a continuously discharging conveyor located to receive material from the virbratory conveyor, means operated by said controller member when the continuously discharging conveyor receives an overfeed greater than the selected normal feed to increase the impedance of the pulsatingcurrent and reduce the current supplied to the vibratory conveyor to produce an underieed less than said selected normal feed, and

means operated by said controller member when the continuously discharging conveyor receives an underfeed less than the selected normal feed to decrease the impedance of the pulsating current circuit and increase'the current to produce an overfeed greater than said selected normal feed.

11. The structure of claim 10 characterized in that the means operated by the controller member' includes a vacuum enclosed switch to change the impedance in the pulsating circuit. 12. The structure of claim 10 characterized in that said continuously discharging conveyor is vibrated to distribute the underfeed and overfeed amounts of material longitudinally over the surface of said conveyor .'to reduce the lag in the correction of the feed thereto.

13. In apparatus of the character described, a

' weighing device, a continuously discharging conveyor on said weighing device, a controlled vibratory conveyor having an actuating circuit and arranged to feed material to said discharge ing conveyor, manually adjustable means to supply a' selected normal feed current to said vibratory conveyor, means operated upon movement of the weighing device when underloaded to -decrease an impedance component in the vibratory conveyor actuating circuit and produce an overfeed greater than the selected normal feed from the vibratory conveyor, and means operated upon movement of the weighing device when overloaded to increase an impedance component in the vibratory conveyor actuating circuit and produce an underfeed less than the selected normal feed from the vibratory. conveyor, the overfeed and underfeed control of the vibratory conveyor establishing an average delivery 'of material substantially equal to 'said selected normal feed by the continuously discharging conveyor.

14. In apparatus of the character described, a

. weighing device, a continuously discharging conveyor mounted on the weighing device, a. controlled vibratory conveyor actuated by current pulsations and arranged to feed material to the discharging conveyor, the feed 01 the vibratory conveyor being proportional to the amplitude of the current pulsations supplied thereto, manually adjustable means for regulating the magnitude of the pulsations to produce a selected feed of material by the vibratory conveyor, means op erated by the weighing device to stop'the feed 0! material from the vibratory conveyor when the amount of material received on the discharging conveyor is incorrect indicating that the amplitude of the impulses should be changed by the manually adjustable means to obtain the selected feed, said last mentioned means operated upon the movement of the weighing device when underloaded to increase the amplitude of the current pulsations to the vibratory conveyor and produce an overfeed greater than said selected feed, means operated upon movement of the weighing device when overloaded to decrease the amplitude of the current pulsations to the vibratory conveyor and produce an underieed less than said selected feed, and means for establishing said overieed and underfeed control of the vibratory conveyor.

15. In apparatus of the character described, a weighing device, a continuously discharging conveyor mounted on the weighing device, a controlled vibrator conveyor actuated by current pulsations and arranged to feed material to the discharge conveyor, the feed of the vibratory conveyor being proportional to the amplitude of the current pulsations supplied thereto, manually adjustable means for regulating the magnitude of the pulsations to produce a selected feed 01! materialby the vibratory conveyor, means operated by the weighing device to stop the feed of material from the vibratory conveyor when the amount of the material received on the discharging conveyor is greater than the selected feed indicating that the amplitude of the impulses should be changed by the manually adjustable means to obtain the selected feed and to restore the feed of material from the vibratory conveyor when the material received on the discharging conveyor is substantially the selected feed, said last mentioned means operated upon the movement of the weighing device when underloaded to increase the amplitude of the current pulsations to the vibratory conveyor and produce an overieed greater than said selected feed, means operated upon movement of the weighing device when overloaded to decrease the amplitude of the current pulsations to the vibratory conveyor and produce an underfeed less than said selected feed, and means for establishing said overi'eed and underfeed control of the vibratory conveyor.

CARL S. WEYANDT.

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