US 2276383 A
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Description (OCR text may contain errors)
March 17', 1942. E. v. FRANCIS 2,276,333
GQRSTAKT GAPKGITY FEEDER Original Filed March 10*, 1958 8 Sheets-Shei l V FRANCE; BY
March 17, 1942. E. v. FRANCIS 2,
- CONSTANT CAPACITY FEEDER Original Filed March l0, 1938 8 Sheets-Sheet 2 I my //YvE/-/T0R: EARLE V FRANCIS,
ATT'Y Original Filed March 10, 1938 Sheets-Sheet 3 JWENTOR V. FRANCQ Marh 17, 1942.
E. v; FRANCIS CONSTANT CAPACITY FEEDER 8 Sheets-Sheet 4 Original Filed March 10, 1958 fiwavroe EAELE \l FRANCIS,
ATT'Y March 17, 1942. E. v. FR ANClS CONSTANT CAPACITY FEEDER Original Filed March 10, 1938 8 Sheets-Sheet 5 March 17, 19 2. E. v. RANCIS 76,383
CONSTANT CAPACITY FEEDER Original Filed March 10, 1938 8 Sheets-Sheet 6 March 17, 1942. v; F N s 2,276,383
CONSTANT CAPAC ITY FEEDER Original Filed March 10, 1938 8 Sheets$heet 7 "3 l f f //YVE/\/7'ORI & EARLE V. FRANCIS,
BY 661M ATT Y.
March 17, 1942.
E. v. FRANCIS CONSTANT CAPACITY FEEDER Original Filed March 10, 1938' 8 Sheets-Sheet 8 EARLE V FRANCIS) Patented Mar. 17, 1942 CONSTANT CAPACITY FEEDER Earle V. Francis, Columbus, Ohio, assignor to The Traylor-Vibrator Company, a corporation of Colorado Original application March 10, 1938, Serial No.
1939, Serial No. 275,947
This invention relates to apparatus for feeding granular material at a regulated rate, and one of the objects of the invention is the provision of improved and efficient apparatus and controlling means therefor, to effect the feeding of various kinds of granular material continuously at such weight rate as may be predetermined.
Another object of the invention is ,to provide improved controlling means operated by a belt conveyor pivotally mounted at its discharge end, and operative to regulate a feeder of granular material to such conveyor that disturbances caused by landslides" from the discharge end of the conveyor shall be reduced to a minimum or eliminated and thereby secure uniformity of delivery of such material from the conveyor by weight per unit of time.
A further object of the invention is the provision of automatic controlling means operated by variations of Weight of material being transierred by a continuously operated traveling conveyor to regulate an electric vibratory feeder associated with such conveyor to secure discharge of material from the latter at a regulated rate.
Another object of the invention is to provide automatic control means for a vibratory feeder associated with a belt conveyor, to efiect such regulation of the feeder as to secure discharge from the conveyor at a regulated weight rate.
Another object of the invention is the provision of improved means operated by variations of weight of granular material on a traveling belt conveyor to regulatethe feeding of the material to the latter to compensate quickly for small amounts of such variations but to retard such compensation when such variations are relatively large and thereby rendering gradual an adjustment of the weight rate discharge from the traveling conveyor.
Still another object of the invention is to provide a constant weight or constant capacity feeder which may be employed with a great many different granular materials and which will insure a substantially constant delivery of materials at any selected rate of delivery regardless of the type of granular material being delivered thereby,
Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.
In the accompanying drawings- Fig. 1 is a side elevational view of the apparatus comprising my invention;
Fig. 2 is a plan view of the apparatus of Fig. 1;
Fig. 3 is a sectional elevatonal view of the apparatus of Figs. 1 and 2 taken on the line 3-3 of Fig. 2 of the drawings, except that the vibra- Divided and this application May 26,
view taken on the line 4-4 of Fig. 1 looking in the direction of the arrows;
Fig. 5 is a transverse sectional and elevational view taken on the line 55 of Fig. 1 looking in the direction of the arrows;
Fig. 6 is a plan view of a portion of the apparatus taken on the line 6-6 of Fig. 1 looking in the direction of the arrows;
Fig. '7 is a side elevational view of a detail, parts being broken away in the interest of clearness;
Fig. 8 is a sectional elevational view of a modified form of control switch for the delivery mechanism;
Fig.9 is a sectional view taken on the line 9--9 of Fig. 8 looking in the direction of the arrows;
Fig. 10 is an enlarged view of the control switch for the vibratory feeder;
Fig. 10 illustrates a detail;
Fig. 11 shows the interior of the control box for the system with the electrical connections omitted in the interest of clearness;
Fig. 12 is a transverse sectional view through the control box of Fig. 11;
Fig. 13 is a wiring diagram for the motor of the delivery mechanism;
Fig. 14 is a plan view of the delivery mechanism with the storage hopper removed;
Fig. 15 is a sectional elevational view of the delivery mechanism;
Fig. 16 is a side elevational view of the delivery mechanism the reduction gearing thereof shown in section;
Fig. 17 is a sectional elevational view through the upper portion of the delivery mechanism taken on the line "-41 of Fig. 14; and
Fig. 18 is a wiring diagram for the apparatus.
This application is a division of my application Serial No. 195,092, filed March 10, 1938, entitled Constant capacity feeder.
It has been found in practice that there is a tendency for certain material to landslide when discharged from a belt conveyor and therefore in constant capacity or constant weight feeding apparatus if the material is discharged from a constant speed belt conveyor at a point remote from the pivotal axis of said conveyor, the normal equilibrium of the balanced conveyor is disturbed by these landslides which prevents extreme accuracy. In the apparatus comprising my invention the material is fed toward the pivotal aXis of the constant speed conveyor and. is discharged substantially at this pivotal axis at which position its influence upon the balance of the balanced constant speed conveyor is substantially negligible, on account of the relatively small lever arm.
It has furthermore been found that when certain granular materials were attempted to be fed, such as pulverized limestone and lime, Carltons earth and activated carbon, or any similar pulverulent material under 200 mesh, said material would tend to flow much after the fashion of a the material in the bottom of the feeder hopper regardless of the amount of material in the primary or storage hopper, thus insuring accurate control of the material by the feeder under the influence of the balanced constant speed conveyor. As a consequence, the apparatus comprising my invention can treat a wide range of materials and deliver said materials in a constant amount with extreme accuracy, which amount may be variably adjusted, as hereinafter described in full detail.
Referring particularly to Figs. 1, 2, 3 and 4 of the drawings, the apparatus comprises a main frame formed by a pair of longitudinally extending channel members 2!, 2| to which are rigidly attached a plurality of transversely extending channel members 22 and transversely extending angle members 23.
Adjacent the rear end of the main frame 20 and extending upwardly from the channel members 2 I, 2| is a pair of spaced apart brackets 24, 24 upon which are mounted housings 25, 25 for antifriction ball bearings which bearings are adapted to support pivotally'a pair of spaced castings or brackets 23, 26 (see Fig. 5) which are rigidly attached to plates 21, 21 rigidly attached to and forming a part of therear end of a frame 28 of a constant speed belt conveyor 29. The constant speed belt conveyor 29 comprises a rear or drive drum or pulley 30 formed by a shaft 3| and a plurality of spaced apart vertical discs 32 which are welded to said shaft 3| and which carry on their peripheries a plurality of transversely extending slats 33 thereby making a corrugated surface for said drum 30 to insure uniform driving of a continuous fabricated rubber belt 34 of i the drum or pulley 39 is driven from the constant speed motor 33 through appropriate speed reduction mechanism and that said motor 38 is supported from the frame29 of the belt conveyor 29. I also preferably provide a guard 4| for the sprockets and 40 and the chain 39.
Adjacent the opposite or material receiving end the belt conveyor 29 is provided with an adjustable pulley or drum 42 which is generally similar in construction to the drum 30, but is preferably of smaller diameter. The drum 42 is provided with a supporting shaft bearing 43 the ends of which are slidably supported in end plates 44 rigidly attached to and forming a part of the frame 28, which plates are provided with elongated notches 45 adapted to receive milled ends of the bearing shaft 43 and to hold said shaft against rotation while permitting sliding move ment thereof. Belt tensioning rods 43 provided with adjusting nuts 41 cooperate with the shaft 43 to adjust the position thereof in the elongated notches or slots 45 to maintain the belt 34 under proper tension at all times.
In order to support the belt between the drums 30 and $2, I provide a plurality of closely spaced anti-friction mounted idler rollers 48 which are carried by the conveyor frame 28.
Positioned above the belt 34 and carried by the frame 23 by brackets 53 and forming a housing for materialcarried thereby, is a hood formed by top plate 49 and spaced upright side plates 50, 50 (see Fig. 5), which carry at their bottoms flexible wiping strips 5|, 5| preferably made of strips of rubber which are rigidly attached to the plates 50, 50 by riveted angle members 52, 52, the bottoms of the wiping strips 5|, 5| having wiping sliding contact with the upper run of the belt 34 and prevent any material being discharged laterally of said belt in its course of travel. At its rear end the above mentioned hood is extended upwardly and rearwardly, as seen at 53. and is provided with an opening 54 for a purpose hereinafter described in complete detail.
Also mounted upon the frame 28 of the conveyor 29 is a counting mechanism 55 adapted to count the units of belt length the belt 34 has moved in any desired time. For example, the counting mechanism 55 will give a direct indication of the number of feet of effective belt travel for any given period of time, which is useful in determining the total weight or amount of material fed over any given length of time, as hereinafter set forth in complete detail.
From the above description it is evident that the entire belt conveyor 29 is pivoted at its rear or discharge end for free pivotal movement about the axis of the shaft 3|. It is, of course, evident that the material received by the conveyor 29 a will be received adjacent the left-hand end, as viewed in Figs. 1 and 2, and travel toward this pivotal axis, as a consequence of which the effectiveness of any particle of material received by said conveyor 29 is progressively reduced, and that the material on the conveyor 29 directly above the shaft 3| will have substantially no influence whatever in determining the effective weight of said conveyor 29 and the material thereon. It may furthermore be mentioned that the electric motor 35 is a constant speed type of electric motor, preferably a synchronous alternating current motor, and thus it is evident that the conveyor 29 will travel at a constant speed.
To provide for the counterbalancing of the belt conveyor 29 about the pivotal point along the axis of the shaft 3|, together with any material carried by said conveyor, and to provide for an adjustment of the amount of material carried by the conveyor necessary to establish a condition of balance, the forward or material receiving end of the conveyor 29 is mounted upon adjustable scale or weighing mechanism now to be described. As best seen by reference to Figs. 3, 4, 6 and '7 of thedrawings, the conveyor frame 28 is provided at its front or material receiving aarases end with a pair of spaced apart downwardly extending angle members 51, formed rigidly therewith.
Adjacent their bottoms the angle members 51 are rigidly attached to a transversely extending angle member 58 and a spaced upstanding bar 59. The angle member 58 and bar 59 form a cross beam which is a rigid unitary part of the frame 28 of the belt conveyor 29. Near to but spaced from said cross beam is a channel member 69 (see Fig. 3) the ends of which are rigidly attached to the Channels 2|, 2| of the main frame 20, which channel member 69 has rigidly attached thereto an angle member 6|. Upon the horizontal flange of the angle member BI is a pair of spaced apart knife edge bearing blocks 62, 62 each of which is adapted to receive a double knife edge 63, carried by crank arms 64, 64 which are rigidly attached together by a transversely extending pipe 65 to which each of said crank arms 64 is rigidly connected, as by a set screw 66 (Fig. 6).
Intermediate the knife edge bearing 63 and the pipe 65 each of the arms 64 is provided with a flexible connection to the cross beam formed by angle member 58 and bar 59 in the form of a clevis 61, connected to an eye-bolt 61.
Adjacent one end, the pipe 65 has rigidly attached thereto a casting 68 (see Fig. 6) rigidly attached to the pipe 65 by set screw 69. As best seen by reference to Fig. 6 of the drawings, the casting 68 has a diametrical groove adapted to receive a lever arm 19 which is rigidly and removably attached thereto by a pair of spaced bolts H, H. drawings, the lever arm 19 has its rear end supported by a hang rod 12 of a beam scale mechanism 13 which is mounted in a housing 14 supported upon a pair of brackets I5, 75 rigidly attached at their bottoms to the main frame 29. The housing 14 preferably has a front door which is readily opened to afford access to the adjustable weight I6 of the beam scale mechanism 13, to adjust the amount of material necessary to balance the belt conveyor 29.
It should be particularly understood that the tube 65 is free to move up and down bodily to a limited extent. The assembly comprising the tube 95, arms 64 and lever arm 19, is supported solely by the knife edge bearings 63 on the bearing blocks 52, 62 and by the abutment (2' at the lowermost end of the hang rod I2. Movement of the tube 65 longitudinally of itself or transversely of the machine is prevented by the knife edges 63, 63 being confined between the spaced abutments 62', 62, shown in Fig. 6.
As shown in Fig. '7, the clevis 61 is provided with rings at its upper ends on opposite sides of the arm 64, to fit over the knife edges 67 which project laterally from opposite sides of the arm 64. Extending from the righ -hand end of the arm I9, as shown in Fig. 7, is a finger 19' located between the upper and lower abutments I2 and 12" at the lower end of the hang rod 12.
It will be evident from a consideration of the above described mechanism that the adjustment of the weight 16 along the scale beam will enable regulation to be made of the weight of material delivered from the discharge end of the conveyor 29 in any given time. That is, the setting of the weight I6 on the scale beam predetermines the weight rate discharge per unit of time.
While the conveyor is being driven at a con stant predetermined speed, the feed of the material to the receiving end of the conveyor may As best seen in Figs. 1 and 7 of the be regulated to maintain uniform the weight of material on the conveyor as predetermined by the setting of the weight 16 in the scale beam mechanism 13. The receiving end of the conveyor and the material on the conveyor continue to be balanced by the scale beam mechanism during uniform discharge of material.
When the angle members 51 are depressed the cross-bar 58, 59 acts through the clevis connections to move the tube down on the knifeedge bearings 92 as a fulcrum, and consequently the finger 19' acts on the lowermost abutment 12" to depress the hang-rod 12. When theangle members 57 rise, the cross-bar 58, 59 frees the clevis connections and permits the scale beam mechanism to act to lift the tube 65 on the knifeedge bearings 62 as a fulcrum.
It may be stated that the beam of the beam scale mechanism 13 is preferably calibrated for various materials in connection with a separate chart showing what amount of any particular material will be discharged per unit of time when the weight is on any particular point on the scale beam. It is also evident that balancing means TI is provided for said mechanism 13 and that in addition to the weight 16, removable weights may be attached to or removed from the beam thereof in a well-known manner.
The parts of the conveyor 29 and those parts by which it is connected to the beam scale mechanism 13, are preferably so designed that the weight 16 may be placed on the zero position of the beam and said beam scale mechanism 13 adjusted to bring the conveyor 29 into a condition of equilibrium with no material whatever thereon. As a consequence, the weight 16 may be adjusted to determine the amount of material which must be on the pivoted conveyor 29 to establish again this condition of equilibrium.
Adjacent the discharge end of the conveyor 29 I provide a discharge hopper or housing 18 (see Fig. l) which is rigidly attached to the main frame 29 and this is independent of the conveyor 29 and acts to receive material discharged by the conveyor 29 and direct it into any desired receptacle.
To prevent any clinging of material to the belt 34 I provide a wiper mechanism 19 in the housing '18 which wipes it free of any adhering material, said wiper mechanism 19 comprising a transverse member contacting the entire width of the belt and a pair of pivoted arms at each end thereof, the mechanism being held in wiping position by a spring tension hang rod 80.
In order to provide for the feeding of material, such as granular material, to the balanced constant speed conveyor 29 at a rate which may be controlled in small'increments or in a continu ously progressive manner, while providing for the feeding of said material in a relatively uniform manner, and over substantially the entire width of the belt 34, I provide an electro-magnetic Vibratory feeder or conveyor 8| which may follow substantially the structure of the vibratory feeder disclosed in the application of James A. Flint, Serial No. 73,318 filed April 8. 1936, now Patent No. 2,251,586, dated August 5,1941. except for the .fact that said feeder will not have any grizzly or grid as disclosed in said application, or it may follow the structure disclosed in the patent to ,James A. Flint, No. 2,094,787 dated October 5,
Briefly described, said electro-magnetic feeder or conveyor 8| comprises a trough shaped deck 82 which has a width substantially equal to the 83 which is rigidly attached to the centers of a plurality of transversely extending spring bars 84, the ends of which are rigidly clamped in a casting 85 forming the main frame of the feeder 8 I. The spring bars 84 lie in a plane which forms an acute angle with the plane of the deck 82 so that when the armature shaft 83 and the deck 82 are vibrated a conveying action toward the right as viewed in Fig. 3, will be imparted to any material carried by said deck 82 due to the composite action of the vertical and horizontal components of movement thereof.
Adjacent its rear end the armature shaft 83 carries an armature 86 preferably built up of laminated steel which is acted upon by a field structure 81 including a laminated iron core, which field structure is excited from alternating or mixed current to cause vibration of the armature 86. It may be further stated that the field structure 8i is adjus'tably mounted in a pair of yokes 88 which are rigidly attached to the main frame casting 85. The entire feeder 8| is supported upon a stand 89 attached to the front end of the main frame 20.
The electro-magnetic feeder 8| has the very important characteristics of uniformly distributing over substantially the entire bottom of the deck 82 any granular material received by said deck 82 and discharging it in a relatively uniform stream onto the belt 34 of the constant speed conveyor 29. Furthermore, the rate of feed of this type of feeder may be adjusted between extreme wide limits in relatively small increments so that the material is fed to the balanced constant speed conveyor 29 in a very uniform manner so as not to cause sudden variations in the load on said balanced constant speed conveyor. This is particularly important since it is desirable to feed the material to the constant speed conveyor at its farthest position from the pivotal axis thereof where its effectiveness is a maximum due to the length of the lever arm thereof, which structure is extremely desirable to the end that the material may be fed by the constant speed conveyor toward the pivotal axis thereof to reduce to a minimum the "hunting time or the time that the mechanism reaches a condition of equilibrium, once it is out of equilibrium which, as hereinafter described, is employed to adjust the rate of feed of the feeder 8I.
As was above set forth, there are a number of granular materials, particularly powdered or fine mesh or pulverulent granular materials, which tend to flow like liquid, and it has been found that if a large storage hopper is provided which feeds directly into the deck or pan 82 of the vibratory feeder 8|, it is impossible to control satisfactorily the rate of flow of these materials because when the storage hopper or bin is full of material there is a very large head, or high pressure per square inch, on the material which causes it to flow like a liquid even though the feeder 8| is completely shut off- I therefore provide means which is particularly useful with material of this type but which may be omitted where large grained material or material which does not tend to flow, is employed.
To provide a substantially constant head of material on the deck 82 or, in other words, to segregate the material in the storage hopper from the material which is in direct communication with the deck 82 and to feed from the former to the latter in batches to maintain substantially constant thehead or amount of material supported directly from the deck 82, I provide a feeder accumulator in the form of a hopper of relatively low capacity and relatively low height which is supported from the main frame 20 by upstanding angle members 8|. The hopper has a bottom opening 82 which opens directly into the trough of the deck 82 and which open ing 92 is controlled by an adjustable gate 83. The sidewalls adjacent the bottom of the hopper 80 project into the trough-like deck 82 so that the material in the hopper 90, in effect, rests directly upon the bottom of the deck 82 and due to this overlapping relation there is no spillage of material from the hopper 98 or deck 82.
Positioned above the feeder hopper 90 is a storage hopper 94 which is preferably rigidly bolted or otherwise attached to the bottom of a large storage bin or compartment in which the material to be fed by the constant capacity feeder of my invention is stored.
Interposed between the storage hopper 84 and the feeder hopper 88 is a delivery mechanism which is so constructed as to maintain the segregation of material within the storage hopper 94 and the material within the feeder hopper 88 so that regardless of the amount of material in the feeder hopper 88 or the bin to which it is connected, the pressure exerted by the material in the feeder hopper 9D and any material in direct contact therewith will be definitely limited and will be maintained substantially constant to the end that the feed rate of the feeder 8| will be substantially the same whenever the amplitude of vibration thereof is constant.
The structure of the delivery mechanism 95 is best seen by reference to Figs. 3 and 14 to 17, inclusive, of the drawings, to which attention is now directed. Said delivery mechanism 95 is formed by a casting 86, the top portion of which forms a hopper-like continuation 91 of the storage hopper 94 to which the casting .96 is bolted and by which the delivery mechanism 95 is supported The bottom portion of the casting 96 forms a material transfer chamber 88, communication to which is provided from the hopperlike continuation 91 by way of a restricted opening 99 (Fig. 14) in the integral Web I08 of said casting 96 which forms the bottom of the hopper-like continuation 81 and the top of the material transfer chamber 98. The bottom of the material transfer chamber 98 is formed by a removable disc |8I provided with a restricted opening I02 which is diametrically opposed to the opening 99, as shown in Figs. 14 and 15.
Within the material transfer chamber 98 is a segregator or combined separator and feeder I03 which is adapted to transfer material from the hopper 94 to the hopper 90 when rotated, but to prevent a direct flow of material from said hopper 84. Said segregator N3 is formed by a hub I84 having integral radial wings I85 (there being six in the segregator illustrated) to which are removably attached a plurality of radial blades I08. It will be noted by reference to Fig. 14 of the drawings that the openings 88 and I02 are of such angular relation and radial extension that it is impossible for material to flow from one to the other without being intercepted by one of the blades I08. As a consequence, it is impossible for material to vflow directly from the hopper 94 and out through the opening I02 unless the segregator I03 ,is caused to rotate.
The segregator I03 is mounted upon an upstanding drive shaft I'I which carries at' its top, scraper means I08 adapted to cut or scrape material from the interior walls of the member 91 which carries on its bottom a plurality of angularly disposed blades I09 adapted to force material which may accumulate on the web I00, axially outwardly until it falls through the opening 99.
The drive shaft I01 is driven from an electric motor I I0 through reduction gearing mechanism III (Figs. 15, 16) contained within a housing I I2 all of which is supported by the casting 96. It will thus be evident that whenever the motor H0 is operated the material will be positively transferred from the opening'99 to the opening I02, and unless the segregator I03 is thus rotated material cannot flow from said opening 99 to said opening I02. It will thus be seen that the segregator I03 acts not only as a feeder but also as a multiple radial gate valve between the hopper 94 and the discharge opening I02.
Positioned directly below the opening I02 and forming a tight connection with the disc IN is a chute II3 the bottom of which extends below the top of the hopper 90, as clearly-illustrated in Fig. 3 of the drawings.
Associated with the chute H3 is a removable plate II4 which, in the preferred form of my invention, is removed so that there may be inserted into the chute II3 an electric switch operating mechanism comprising a pivoted plate II5 (see Fig. 3) which carries a tube type mercury switch II6 for opening and closing the circuit of the motor IIO, as diametrically illustrated in Fig. 13 of the drawings.
The operation of the delivery mechanism may be briefly described as follows. Since the chute II3 extends into the hopper 90, both said hopper 90 and said chutell I3 may be substantially completely filled with material without said material running over from said hopper 90. Whenever the chute H3 is not filled with material the pivoted plate II5 will be in its upright position, as illustrated in Fig. 3, and the switch II6 will be closed to cause operation of the delivery mechanism 95' to deliver material from the hopper 94 to the hopper 90. As material tends to build up in the chute II3 the pivoted plate H5 is swung about its pivot to open the contacts of switch I I6 to-shut offthe motor IIO. As a consequence, the hopper 90 will be maintained substantially full of material at all times and when it is full the delivery mechanism 95 will be shut down.
The control mechanism for the motor I I0 may be omitted if desired and the motor IIO run continuously, but the inclusion of such control mechanism is preferred for the sake of economy in the consumption of electric current. For example, if the motor IIO runs continuously whenever the constant weight feeder is to be employed, it will deliver material from the hopper 94 to the hopper 90 until said hopper 90 and the chute II3 are completely filled with material. When this condition is realized, the material received between the blades I06 of the segregator I03 will not fall through the opening I02 but will continue to rotate with said blades I06. As a consequence, the segregator I03 will simply be full of material which will continue to rotate with said blades I06. However, since this rotation does no useful work I prefer to control the motor IIO therefor.
- lever I3I.
the head on the deck 82 is maintained substantially constant.
In Figs. 8 and 9 of the drawings, I have illustrated a modified form of control for the mcrcury switch II6, which may be substituted for that illustrated in Fig. 3 of the drawings. This modified control comprises a frame II'I adapted to replace the cover plate I I4 and to extend into the chute II3. Said frame III is in the form of an enclosing housing provided with a circular opening closed by a flexible diaphragm II8. To the center of the diaphragm H8 is attached an operating slide rod Il9 carrying a disc I20 which bears against a pivoted bell crank lever I2I which is adapted to operate a pivoted lever I22 upon which is supported the mercury switch 6. It will be evident, when this form of operating mechanism is employed, that as the material builds up and fills the chute II3, the diaphragm II8 will yield and move the operating slide rod II9 to the left, as viewed in Fig. 8, thereby to rock the switch II6 through the levers I2I and I22. .The weight of the lever I22 and the switch I I6 are sufficient to return the diaphragm to the position illustrated in Fig. 8 in the absence of material filling the chute I I3.
As has been previously indicated, the balanced or unbalanced condition of the beam scale mechanism I3 is relied upon to control the rate of feed the setting of the weight I6 of beam scale mech-' anism I3 so that said beam scale mechanism will be in equilibrium and any movement from this condition of equilibrium either on the overload or underload side will be employed to control the feed rate of the feeder 6I to compensate To effect this control I provide a switch supporting plate I25 (see Figs. 1 and 10) within the housing I4 upon which is mounted a pair of mercury switches I26 and I2I carried by pivotally adjustable plates I28 and I29, respec tively. Said switches I26 and I2'I are of well known construction and include within themiron attractible armatures I26, I21 (Fig. 18) which will move when a relatively small permanent magnet is placed adjacent the tube of the switch to close the circuit thereof.
Pivotally mounted upon the plate I25 at pivot I30 is a spring lever I3I which carries at its bottom a pair of permanent magnets I32 and I33 associated with switches I26 and I2I, respectively. Adjustable stops I34 and I35 are associated with opposite sides of the bottom of said spring When the spring lever I3I is swung to the right, as viewed in Fig. 10 the contacts of switch I26 will be closed and when swung to the left the contacts of switch I2'I will be closed. When in the neutral position, as illustrated in Fig. 10, the contacts of both of the switches I26 and I2I will be open. The spring lever I3I is 0perated by flexible operating lever I36 (see Fig. 1) which is secured to and thus controlled by the beam of the beam scale mechanism I3. Whenever the material on the conveyor 29 is suflicient to over-balance the beam the spring lever I3I will be moved to the left to close the contacts of switch I21 and whenever the material on the conveyor 29 is insufficient to balance said beam the switch I26 will be closed. Whenever the beam is' in its normal or balanced condition, spring I3I will be upright, as illustrated in Fig. 10, and both of the switches I26 and I2'I will be open.
Attention is now directed particularly to Fig. 18 of the drawings, showing the wiring diagram for the apparatus comprising my invention. Three phase alternating current of any desired voltage, such as 440 volts, is supplied over three phase power mains I46 controlled by switch Mi. Also associated with the power mains I40 is a.
solenoid operated main line switch I42 controlled by a solenoid I43. A step-down transformer I4 3 is connected between the switches IIII and I42 so that it will always be energized when switch I is closed without regard to the condition of switch I42. This step-down transformer is em-= ployed to provide 110 volts, or any other desired voltage, on its secondary which is the source of power for the control system.
Leading from the power mains I40 through switch 2 is a three phase alternating current,
motor I45 which drives a direct current generator I46. One of the power mains I40 leads to main conductor II of themotor or power circult and another of them leads to main conductor I49 of the motor or power circuit in the latterof which the D. C. generator I46 is imposed so that mixed current, or a combination of alternating and direct currents, will be supplied to the conductors I41 and I49. As was above pointed out, this mixed current is desirable to operatethe electro-magnetic feeder 9!. In case the feeder 9| is of the type which operates directly from alternating current it is evident that the motor I45 and the generator I48 may be omitted.
The conductor I48 leads directly to the field structure 91 of the feeder 9| and thence successively through hand operated variable rheostats I49 and I50 and motor operated rheostat I5I, all in series, the latter of which is connected by a variable tap to the main conductor I 41. In.
other words, the field of the electro-magnetic feeder 9| is connected through three rheostats I49, I50 and I5I in series, the first two of which are variable by a manual operation and the last of which is variable by a motor, as hereinafter described in full detail.
Associated with the rheostat I49 is a shunt circuit provided by a conductor 25I and a conductor I52 under the control of the contacts of an electro-magnetic switch I53. Also associated with the rheostat I 50 is a shunt circuit provided by conductor I52 and a conductor I under the control of the contacts of an electro-magnetic switch I56.
In the normal condition of the apparatus when the beam scale mechanism I3 is in balance and the switches I26 and I2! are open, the switches I53 and I55 will be in the position illustrated in Fig. 18 with the former closed and the latter opened, under which conditions the rheostat I50 will be effectively in circuit with.
the field 91 of the feeder 8| in series with the rheostat I5I, while the rheostat I49 will be short circuited. It is evident that if both of the switches I53 and I56 are operated to close their contacts respectively, both of the rheostats I49 and I50 will-be shunted, while if both of them are operated to open their contacts respectively, both of the rheostats I49 and I50 will be' effectively connected in series with the field 91 of the feeder 8|. This circuit may be considered as the power circuit while the other circuits may, in general, be considered as control circuits as they are generally of lower voltage, though this is not necessarily the case, as they may all be of the same voltage, if desired.
As above set forth, the voltage for the control circuit is supplied by the transformer I44 from which the conductors I59 and I59 lead to a master switch I60, the latter through a fuse I6I. The closing of the contacts of the master switch I60 produces the following results. It closes the circuit to the solenoid I43 of the switch I42 causing said switch I42 to close its contacts and energize the above-described power circuit, including the feeder 8| and the motorI95. The circuit to this solenoid I43 can be traced through the conductor I58 leading from transformer I44 to and through master switch I60 through continued conductor I58 to branch conductor I62, through solenoid I43, thence by way of conductor I69, fuse I64 in said conductor I63, thence to conductor I59, leading to and through master switch I60 and fuse I6I, which leads back to the transformer I44. It also illuminates a signal lamp I65 connected across conductor I59 and branch conductor I66 which, in turn, is connected to conductor I59. In addition, it starts the synchronous motor 36 for driving the constant speed conveyor 29 over branch conductors I61 and I69 which are connected respectively to conductors I69 and I62. It is thus evident that the closing of the master switch I60 will illuminate the light I65 to indicate that the apparatus is in operation, will start the constant speed motor 36 of the conveyor 29 and will start the operation of the electro-magnetic vibratory feeder 9|. This, of course, will place the entire apparatus in operation whereupon material will be fed by said vibratory feeder 9| to the constant speed conveyor 29 and by it delivered to any desired receptacle, or the like. As above set forth, this normal operation will take place with the rheostats I50 and I5I connected in series with the field 91 of the electro-magnetic feeder BI and with the rheostat I49 shunted.
The control system for the feeder 9| is so designed that in response to an underweight of material on the constant speed conveyor 29 the rate of feed of the feeder 9I will be increased to re-establish a condition of equilibrium and a condition of overweight on the conveyor 29 will produce a decrease in the rate of feed of the feeder 9I for the same purpose.
' The system is furthermore so designed that in case either an overload or underload condition exists for a prolonged predetermined time interval there is a further adjustment which is more permanent in its nature, the first two mentioned adjustments being substantially instantaneously responsive to a condition of non-equilibrium and the last mentioned adjustment being only responslve to a sustained condition of nonequilibrium. The rheostats I49 and I50 are controlled for the Instantaneous adjustment of the rate of feed of the feeder 9I and the rheostat I5I is controlled in response to a sustained condition of non-equilibrium.
To provide for this complete and automatic adjustment of the rate of operation of the feeder 9I to maintain within very small limits the constant rate of feed of the mechanism, I provide the additional controls now to be described. As was previously described, the conductor I63 is connected to the conductor I59 leading to transformer I44, and the conductor I66 is connected to theconductor I58 also leading to the transformer I44 when the master switch I60 is closed. Connected across conductors I63 and I66 are the primaries of transformers I and HI,
Leading from the secondary of the transformer I10 is a pair of conductors I12 and I13, former of which includes in circuit therewith the solenoid of electro-magnetically operated mercury switch I14 and leads to a common branch conductor I 15 having a control switch I16 therein which conductor I15 is common to a terminal of each of the mercury switches I26 and I21. The conductor I13 leads directly to the other terminal of the mercury switch I26. In a similar manner the secondary of the transformer I1I is connected to conductors I11 and I18 the former of which includes in circuit therewith the solenoid of electro-magnetically operated mercury switch I19 and leads to the aforementioned common conductor I15. Conductor I18 leads directly to the other or non-common terminal of the mercury switch I21.
The closure of the contacts of mercuryswitch I26 in response to a sub-normal load on the constant speed conveyor 29 energizes the solenoid of electro-magnetic switch I14 which operates to close the contacts of the mercury switch I80 associated therewith, and likewise the closing of the contacts of the mercury switch I21 in response to an overload on the constant speed conveyor results in an energization of the solenoid of electro-magnetic switch I19 and the closing of the contacts of the mercury switch I8I associated therewith. A closure of the contacts of mercury switch I80 is effective to connect the green or underload lamp I82 across the conductors I63 and I66 which are energized, as previously described, and thus illuminate this lamp and at the same time energize the solenoid I83 of a master relay I84 by connecting it across said conductors I63 and I66 by way of conductor I85.
In a similar manner, a closure of the contacts of the mercury switch I8I is effective to connect the red or overload lamp I86 across the conductors I63 and I66 and thus illuminate this lamp and at the same time energize the solenoid I86 of a master relay I81 by connecting it across said conductors I63 and I66 by way of conductor I68.
The operation of the master switch I84 is effective through the third set of contacts, as viewed from the right, to close a circuit from the energized conductor I63 by way of conductor I89 to the solenoid I51 of the control switch I56 controlling the shunt circuit for the rheostat I59 and thereby shunting said rheostat I50, the circuit being completed from said solenoid I51- of switch I56 by way of common conductor I90 which'is connected to the other energized conductor I58 over branch conductor I62. It is thus evident that when the load on the constant speed conveyor is light, mercury switch I26 will be-closed and this, in turn, will result in the shunting of rheostat I50 thereby increasing the previous rate of feed of the feeder 8|.
In a similar manner the operation of the master switch I81 is effective through the third set of contacts, as viewed from the right, to close a circuit from the energized conductor I63 by way of the conductor I9I to the solenoid I54 of the control switch I53 controlling the shunt circuit for the rheostat I49 and thereby removing the normal shunt from said rheostat, the circuit being completed from said solenoid I54 of switch I 53 by way of said common conductor I90. It is thus evident that when the load on the constant speed conveyor is heavy, mercury switch I21 will be closed and this, in turn, will result in the removal of the normal shunt around rheostat I49 thereby decreasing the previous rate of feed of the feeder 8|.
It is thus'evident that any variation which causes a disturbance of the equilibrium of the constant speed conveyor 29 will have as its immediate effect a compensating adjustment of the rate of feed of the electro-magnetic feeder 8|.
It is further evident that by adjusting the position of the weight 16 on the beam scale mechanism 13 the capacity of the feeder may be set at any adjustable desired value from substantially zero capacity to the full capacity of the machine.
The above described automatic adjustments of the rate of feed of the feeder M by the selective shunting of the'rheostats I49 and I50 may be termed instantaneous or immediately responsive adjustments as they are intended primarily to compensate immediately for conditions of unbalance which' are of a short time interval and other means are relied upon to compensate for conditions of unbalance of a prolonged period which, for example, might be encountered upon and adjustment of the weight 16 to change the capacity of the feeder from one value to another.
It may further be mentioned that the rheostats I49 and I50 are made independently manually adjustable so that depending upon conditions as encountered in practice the amount of change in the feed rate of the feeder 8| when the relays I53 and I56 are operated may be adjusted so that this change in feed rate may be relatively small or relatively large or any intermediate value.
When either of the master relays I84 01 I81 is operated, the left-hand contact of the operated relay is effective to close a circuit by way of conductor I92 to the field coil of a reversible motor'forming part of a time delay relay I93 by connecting said coil across the conductors I63 and I58, the latter by way of branch conductor I92, which conductors I63 and I58 are energized as above described.
Associated with and forming a part of the motor of said time delay relay I93 are two shading coils I94 and I95, the former of which is shunted whenever the master relay I81 is energized by the closing of the extreme right hand contacts thereof over common conductor I96 and conductor I91. In a similar manner the extreme right hand contacts of the master relay I84 are effective when operated to provide a shunt for the shading coil I94 by way of common conductor I96 and conductor I98. The shading coils I94 and I are operated to determine the direction of r0- tation of a rotor I99 of said motor of the time delay relay I93 so that when master relay I81 is operated, said rotor I99 will rotate in one direction and when master relay I84 is operated it will rotate in an opposite direction.
Associated with and forming a part of the master or time delay relay I93, the structure which is described in more complete detail hereinafter, are two mercury switches 200 and 20I, the former of which is controlled by the second group of contacts of the master switch I84 and the latter of which is controlled by the second group of contacts of master switch I81 over conductors 202 and 203, respectively, and which are operative to control the direction of rotation of a reversible seriesmotor 204 which is operative to adjust the position of a sliding contact 205 to determine the effective portion of the rheostat II which is included in circuit with the field 8i of feeder 8i. To this end the reversible series motor 204 has a common conductor 209 which is connected to the conductor I63 through fuse 201, which conductor I69 is energized as previously described.
The circuit through the mercury switch 200 leads by way of conductor 208 to one series field 209 of the motor 206 which, when energized, causes said motor to rotate in one direction and in a direction to decrease the effective resistance of said rheostat Hit thereby to increase the rate of feed of the feeder 83!.
Likewise, the circuit through the mercury switch 20! leads by way of conductor 2l0 to another series field 2M of'the motor 204 which,
when energized, causes said motor to rotate in the opposite direction to increase the effective resistance. of said rheostat Ithereby to decrease the rate of feed of the feeder 9|.
As above set forth, the motor 204 is only operated to adjust the rheostat I5I in response to a sustained or prolonged condition of unbalance of the constant speed conveyor 29. It may be pointed out that even though the mercury switches 200 and 2M are closed they will not be effective unless switch 200 is closed at the same time that the contacts of master relay I84 are closed or switch 20% is closed at the same time the contacts of master relay I81 are closed.
In Figs. 11 and 12 of the drawings, to Whichattention is now directed, there is illustrated a control box 2I2 which may be mounted on any appropriate control panel, as illustrated in Fig. 3 of the drawings, from which a cable 2l3 may extend to the feeder mechanism. In said Figs. 11 and 12 of the drawings, substantially all of the electrical conductors have been eliminated in the interest of clearness.
No particular description of the apparatus here disclosed appears necessary as these drawings merely show the relative positions of the various switches, relays and lights which are identified by the reference characters given them. It may be pointed out, however, that within the control box 2I2 is a terminal block 2 to provide for ready connection and disconnection of all of the control circuits and a terminal block 2I5 to provide for the connection and disconnection of the power circuits. It may additionally be pointed out that the time delay relay I93 includes a rotary motor having a rotor I99 (see Fig. 18) with which is associated reducing gears 2I6 which drives a rotating shaft 2|! carrying a rotating pin 2 I8.
Positioned in the path of the rotating pin 2; is a contact pin 2 I8 carried by a rotatably mounted disc 220 which, on the opposite side thereof, carries three pins 22I. The pins 22I are adapted to contact pivoted cams 222 and 223 (see Fig. 11) which carry the mercury switches 200 and 20I, respectively. It is evident that rotation of the disc 220 will cause successive opening and closing of the contacts of each of the switches 200 and 20I. Each time the switch 200 has its contacts closed it will operate the motor 204 a relative short distance until said contacts are open again, provided master relay I84 has its contacts closed, as previously described. A similar condition will apply to switch 20I when master switch I81 has its contacts closed.
It is evident that whenever the disc 220 is retated in one direction by the pin M8 the rotor I 99 of the time delay relay I93 must be rotated in the opposite direction through substantially a complete revolution so that the pin 2I8 will make contact with the opposite side of the pin 2I9 before said disc 220 can be rotated in the opposite direction. This provides for the time delay feature of the relay I93 and requires that the con-' tinuous conveyor 29 be out of balance for a prolonged period of time either as too light or too heavy or that it be out of balance successive short periods of time on one side before adjustment of the rheostat 955 is effected. For example, if the equilibrium of the system is upset so that the master relay @8 3 is maintained energized for a prolonged period, the, time delay relay I93 will operate to send successive impulses which decrease the effective resistance of the rheostat IEI in successive steps until a condition 01' equilibrium is established. Also, if the master relay M36 is operated successively a number of times without the master relay l8! acting between these successive operations a similar resulting adjustment of rheostat l5l will be effected.
It is, of course, evident that an opposite condition or a sustained unbalancing of the system due to overload will cause a reverse operation of the rheostat I56 under the influence of the master relay I 81. This adjustment of the rheostat I! is such that the system is entirely automatic to adjust the normal feed rate of the feeder 8! to correspond to any desired capacity of the entire feeder which may be widely adjusted, as aforesaid, and the instantaneously responsive adjustments of the rate of feed of the feeder 8| are effected by the rheostats I 49 and I50.
In the operation of the apparatus comprising my invention, granular material, which is intended to embrace substantially any material other than a fluid, to be fed at a constant rate will be stored in a large hopper or storage bin with the bottom of which is associated the hopper 94; This granular material is fed from the hopper 94 by the delivery mechanism 95 into the material accumulator or feeder hopper at such a rate as to maintain the material in said feeder hopper 90 substantially constant, or, in other' words, to maintain said hopper 90 substantially full of material at all times thereby providing a substantially constant head of granular material on the deck 82 of the electro-magnetic vibratory feeder 8 I.
It may be stated that, if desired, the hopper 90 may be eliminated entirely and the chute II3 extended downwardly below the top of the deck 82 and provided with a gate 93 or not, as desired.
It may also be pointed out that the control mechanisms for the motor IIO of the delivery mechanism 95, as illustrated in Fig. 3. or as illustrated in Figs. 8 and 9, are preferably employed to prevent operation of said delivery mechanism when the hopper 90 is full of material but said control may be omitted if desired. as above set forth.
It is, of course, evident that this delivery mechanism is effective to isolate the granular material in the hopper 94 and the granular material in the chute H3 and hopper 90 to maintain the aforesaid constant head on the deck 82. This provides for a very accurate control of the rate of feed of the material on the deck 92 as determined substantially entirely by the ampli- 1 belt 3| and at a rate which can be instantaneously controlled and which, during normal operation, is very uniform thus not causing any disturbance of the equilibrium bf the balanced constant speed conveyor 29 which would be present if said material were fed in an interrupted or non-continuous or non-uniform manner. This is particularly important in view of the fact that the material is fed to the constant speed conveyor 29 at the position farthest removed from the pivotal point of the frame 28 where it has the maximum disturbing influence due to the fact that the effective lever arm thereof is a maximum. The granular material received by the belt is then conveyed at a constant speed toward the fulcrum point of the pivoted frame 28 of said constant speed conveyor adjacent which it is discharged into the hopper or housing l8 by which it is directed to any desired receptacle. The discharging of this granular material adjacent this pivot point is of importance because some materials tend to form landslides which would disturb the equilibrium of the balanced conveyor 29 if removed from the pivotal point thereof. It is, of course, evident that material which is substantially at the pivotal point has little or no balancing influence on the balanced frame 28 as the length of the lever arm thereof is substantially zero.
By virtue of the afore-described automatic mechanism the rate of feed of the feeder 8! will be automatically adjusted as determined by the setting of the adjustable weight 16 of the beam scale mechanism 13 and once a normal condition of feed of the feeder 8| is determined in this automatic manner momentary variations therefrom which will produce a disturbance of the equilibrium of the conveyor frame 28 will immediately produce a compensating feed rate of the vibratory feeder 8|. As a consequence, the rate of delivery of the apparatus from the constant speed conveyor 29 will be constant within a very small limitation. I
The scale beam may be calibrated in pounds to indicate the weight of material per unit length, of conveyor belt. The counter 55 may indicate the number of such unit lengths. For instance, if the weight is at the ten pounds point during equilibrium operation and the counter indicates 100, the indications are that one thousand pounds have been discharged from the conveyor. Such readings are made independently of the speed of the conveyor.
For normal operations for a selected material with the weight 16 set at a predetermined point on the scale beam, the time delay relay does not come into operation. Only when the weight is widely set from a previous point, or when abnormal fluctuations in line voltage occur, does the time delay relay operation take place to automatically adjust the feeding operations to the disturbing or abnormal conditions. Such conditions are usually only temporary and when normal conditions are re-established, the system disclosed in the drawings acts automatically to restore the normal relation between the feeding and delivery; so as to at all times maintain automatically the uniform weight rate discharge from the conveyor.
It may be further pointed out, where extreme accuracy is not essential, or where there is not a great tendency for the granular material to flow, the delivery mechanism 95 may be omitted and the hopper 94 fed directly into the hopper 90, but in the interest of extreme accuracy, and particularly where the granular material is of the type which tends to flow, as above set forth, it is desirable to employ this mechanism in combination with the other mechanism, as above described.
It is furthermore evident that the delivery mechanism 95 in combination with the hoppers 94 and and the electromagnetic feeder 8| make for an important sub-combination of the entire system which has considerable utility in itself, and may be separately employed where it is desired to feed material from a hopper which material has a tendency to flow under high head and where it is desired to control the rate of feed of said material from substantially zero up to the full capacity of the electro-magnetic feeder 8|.
, Obviously those skilled in'the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.
" Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is:
1. In a feeder, the combination with an electric conveyor, of a control circuit for said conveyor comprising two resistors and a variable rheostat, shunt circuits for each of the resistors, a reversible motor for controlling said variable rheostat, a scale, circuit control means responsive to the position of said scale and so constructed and arranged that when the said scale is in a predetermined normal position one of said resistors will be shunted and when in another position both of said resistors will be shunted, and when in a third position none of said resistors will .be shunted, whereby the delivery rate of said conveyor will be controlled by said scale, and means operative in response to a sustained positioning of said scale from its normal position to eifect operation of said reversible motor in one direction or the other to control said variable rheostat and thereby further control the delivery rate of said conveyor.
2. In feeding apparatus, the combination with an electro-magnetic feeder, of means to control the rate of feed of said feeder in response to a variable condition as normal or abnormal, electrically operable means constructed and arranged to be immediately responsive to an abnormal condition to adjust the feed rate of said feeder, and electrically operable time delay relay means comprising a reversible motor and switches operated thereby constructed and arranged to respond to sustained abnormal condition to adjust the rate of feed of said feeder.
3. In feeding apparatus, the combination with an electro-magnetic feeder, of means to control the rate of feed of said feeder in response to a. variable condition as normal or abnormal, electrically operable means constructed and arranged to be immediately responsive to an abnormal condition to adjust the feed rate of said feeder, and electrically operable time delay relay mal condition to adjust the current flow for said electro-magnetic means,
4. In automatic conveying apparatus, the combination with a conveyor unit, of an electromagnetically operated feeder associated therewith, two resistors and a variable rheostat connected to the electro-magnet of said feeder, means operative by underloads and overloads of materials on said conveyor unit for cutting in and out of circuit said resistors to speed up the feeder for an underload and slow down the feedeii for an overload, and circuits and connections comprising a time delay relay to automatically adjust said variable rheostat to increase the current flow to the electro-magnet of said feeder if an underload persists and to decrease the current flow to said electro-magnet if an overload persists.
5. In a constant capacity feeder, the combination with a main frame, of a conveyor unit pivotally mounted thereon, an electric vibratory feeder for feeding material to said conveyor unit, means comprising a variable rheostat for controlling said electric vibratory feeder to regulate the material fed thereby onto said conveyor, time delay relay mechanism comprising two mercury switches and a reversible electric motor connected thereto to open and close the same, an additional reversible electric motor connected to said variable rheostat, circuits and connections for effecting 'rotation of said additional electric motor in one direction when one of said mercury switches is closed and in the opposite direction when the other mercury switch is closed, and means controlled by the tilting of said conveyor unit due to the load thereon to effect operation in one direction or the other of said time delay relay mechanism to effect increase or decrease of the feeding of material onto said conveyor unit.
6. In a constant capacity feeder, the combination with a main frame, of a conveyor unit comprising an endless conveyor belt on a conveyor frame pivotally mounted on said main frame, means comprising a driven shaft at the pivot for driving said conveyor belt, an electro-magnetic vibratory feeder for feeding material to said conveyor belt remote from the pivotal means for balancing said frame with a predetermined load on the upper run of the conveyor belt, a rheostat for controlling said electro-magnetic feeder, means acting quickly to control said rheostat when said conveyor unit becomes unbalanced, a variable rheostat, a reversible electric motor connected to said variable rheostat to control the same, and time delay relay mechanism for controlling the direction of rotation of said reversible electric motor when overload or underload of material on said conveyor unit persists, in order to regulate said electro-magnetic feeder to restore the balanced condition of said conveyor unit.
7. In a constant capacity feeder, the combination with a main frame, of a conveyor frame pivotally mounted on said main frame about a pivot at one end thereof, a conveyor belt on said conveyor frame, means for driving said conveyor belt to transfer material toward said pivotal axis and discharge such material adjacent said axis, scale mechanism for supporting the tilting end of said conveyor frame, a vibratory feeder mounted on said frame'in position to feedmaterial to said conveyor belt at the tilting end of said conveyor frame, and automatic means operated by said scale mechanism to control said vibratory feeder to regulate the amount of material fed to said conveyor belt in accordance with the tilting of conveyor frame due to variation of the loadof material on the upper run of the conveyor belt.
8. In a constant capacity feeder, the combine. tion with a main frame, of a conveyor frame pivotally mounted on said main frame about a pivot at one end thereof, a belt conveyor on said conveyor frame constructed to deliver material toward said pivotal axis and discharge it adjacent said axis, ascale mechanism supporting the other end of said conveyor frame for pivotal movement,. a vibratory feeder mounted on said main frame and positioned to feed the end of said conveyor removed from said pivotal axis, said feeder being under the control of said conveyor frame.
9. In feeding apparatus, the combination with a stationary main frame, of a conveyor frame pivotally connected to said main frame, conveyor mechanism comprising an endless belt carried by a pair of spaced-apart parallel drums one of which is mounted to rotate on the axis of the pivotal connection between said conveyor frame and said main frame, a motor mounted on said main frame, driving mechanism between said motor and the drum rotatable on said pivotal axis to drive the upper run of said endless conveyor belt toward said pivotal axis, and vibratory feeder means for feeding material to said upper run from a position remote from said pivotal axis for transfer of such material toward said pivotal axis and delivery from said belt adjacent to said pivotal axis.
10. In a feeder, the combination with an electric conveyor, of a control circuit for said conveyor comprising two resistors and a variable rheostat, shunt circuits for each of the resistors, a reversible motor for controlling said variable rheostat, a condition indicator, circuit control means responsive to the position of said indicator and so constructed and arranged that when the said indicator is in a predetermined normal position one of said resistors will be shunted and when in another position both of said resistors will be shunted, and when in a third position none of said resistors will be shunted, whereby the delivery rate of said conveyor will be controlled by said indicator, and means operative in response to a sustained positioning of said indicator from its normal position to effect operation of said reversible motor in one direction or the other to control said variable rheostat and thereby further control the delivery rate of said conveyor.
11. In a feeding system, the combination with an electric feeder, of two resistors and a variable rheostat connected to said feeder to control its feed rate, a condition indicator, means operative thereby in response to under and over normal conditions for cutting said resistors in and out of circuit to speed up said feeder for an under normal condition and slow it down for an over normal condition, and circuits and connections comprising a'rotary time delay relay to adjust said variable rheostat automatically to increase the current flow to said feeder if the under normal condition persists and to decrease the current flow thereto if the over normal condition-persists.
EARLE V. FRANCIS.