US 2430407 A
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Nov. 4, 1947. J. H. NELSON HOP PER FEED CONTROL Filed July 18, 1946 3 Sheets-Sheet 1 Nov. 4, 1947. J. H. NELSON HOPPER FEED CONTROL Filed July 18, 1946 s Sheets-Sheet 2 Nov. 4, 1947.
J. H. NELSON 2,430,407
HOPPER FEED CONTROL Filed July 18, 1946 3 Sheet'sSheet 5 Patented Nov. 4-, 1947 Liidit? OFFICE HOPPER FEED CONTROL James H. Nelson, Ladoga, Ind., assignor to Bradford B. Nelson, Ladoga, Ind.
Application July 18, 1946, Serial No. 684,427
It is a primary object of my invention to provide a feeding means whereby loose material in a relatively large place of storage may be conveyed to a hopper or bin from which it is to be removed from time to time, and to provide in connection therewith a control whereby the feed of material will proceed at a rate which is commensurate with the needs of the hopper from which the material is withdrawn. In the accomplishment of this purpose, I utilize means which are essentially simple and inexpensive, but which may be depended upon to operate automatically with little or no attention or care.
A suggestive embodiment of my invention is set forth in the accompanying drawings wherein:
Figure l is a vertical section through a storage bunker from which is extended a conveyor for feeding loose material to a hopper, the hopper being equipped with means for automatically controlling the operation of the conveyor so as to assure a constant replenishment of the supply of material Within the hopper regardless of the rate at which it is withdrawn therefrom;
Fig. 2 is an exterior elevation of the hopper side whereon is supported the two control gates interiorly of the hopper;
Fig. 3 is a top plan View of the hopper;
Fig. 4 is an enlarged sectional detail through the hopper wall, control gates and connections therebetween;
Fig. 5 is a fragmentary side elevational View looking toward the interior of the hopper side whereon the control gates are mounted;
Figs. 6, 7, and 8 are details in section taken,
respectively, on lines ii-G, l-l, and 8-8 of Fig. 4
Figs. 9-12 are more or less diagrammatic views showing the positions of the control gates and parts operated thereby in four successive stages of the cycle; and
Fig. 13, which is a view similar to Fig. 4, shows a modified construction of the apparatus.
In Fig, 1, I have shown a bunker B adapted to contain coal or other loose material. Within th bunker is mounted a rotatable shaft l5 having a sprocket wheel I 6 over which is trained an endless link belt H whereon are angle plates l8. This belt runs over a second sprocket wheel it which is suitably supported over a hopper H at a point remote fro-m the bunker. The belt constitutes a conveyor which passes out through an opening 29 in a wall of the bunker to remove coal therefrom to a point beyond the sprocket wheel I9 where the coal is free to drop through a discharge spout 2| into the hopper H therebelow.
The hopper, as shown, is open at the top with four vertical marginal walls 23 extended upward- 1y from other walls 24 which converge toward the bottom through which is formed a discharge opening 25. A conduit or other conveyor (not shown) may communicate with this opening to educt the coal from the hopper to its intended place of use. Since my invention is concerned primarily with the means whereby a supply of coal is maintained within the hopper in an amount adequate to meet withdrawal demands therefrom, it is unnecessary to consider further the conduit whereby coal is taken away fro-m the hopper.
I affix interiorly of the hopper an inverted U- frame comprising a pair of spaced angle irons 26 connected by a top iron 21. This frame may be bolted or otherwise aflixed securely to the hopper walls 23 and 2 (see Figs. 4 and 5). I thereby provide a suspension mounting for a control gate 30 wherein is formed a pair of opposed sockets 3| one at each end adjacent the top, each for the reception of one end of a bolt 32 which is supported through a web of the proximate angle iron 26. By some such means as this, I provide close to the marginal wall 23 a free pivotal mounting for the gate such that it may swing only inwardly of the hopper.
The vertical position of the gate is such that it extends upwardly beyond the hopper top for a distance sufficient to permit the rearward extension therefrom of an operating arm 35. A web 36 depending from this arm is adapted to be en-- gaged by the oifset rounded end ii] of a leaf spring 3 which is secured as by bolts 52 to a depending angle iron support 33 which is extended in a direction generally parallel with the operating arm 35 for connection with the top bar 21 of the U-frame. In the position shown in Figs, 4 and 8, the offset spring end 48 underlies the operating arm 35 so as to yieldingly support the arm in a position wherein the gate 30 is substantially ertical. The weight of this arm is such that gravity force tends to pull it down, thereby rocking the gate inwardly. Unless there be some restraining force acting against the inner face of the gate, the operating arm 35 will deflect the spring and move downwardly past it to swing the gate inwardly. As by means of a set screw M which bears against the spring, it is possible to adjust its initial position whereby to predetermine the force necessary for movement of the operating arm to its down position.
Upon the hopper wall 245 at a point below the gate 30, I have mounted a second frame consisting of spaced sides 58 interconnected by a top 5|. The frame so formed is open to the interior of the hopper. This frame supports a lower gate 55 having at opposite ends a pair of sockets 51 at the top for reception of bolts 58 which are carried by the frame sides 59 to provide a pivotal mounting for the gate. Extending fixedly and rearwardly from the gate is an operating arm 60 which traverses a slot 6| in the hopper wall 24 to support at 62, near its outer extremity, the upper end of a pull spring 63 whose lower end is anchored to the hopper at a point 64 relatively close to its base. By some such means the weight of the operating arm 68 is augmented by the tension of the spring to induce a downward movement of the arm with a consequent inward swingthe movement of the gate 55.
Along the outside of the hopper is a connecting rod 65 whose lower end is pivotally joined at 66 to the operating arm 60 of the lower gate 55. This rod is extended upwardly substantially parallel with the proximate inclined wall 24 of the hopper to traverse the operating arm 35 of the upper gate 30 (see Figs, 4 and 8). A pair of spaced collars l0 and H are carried by the rod, the upper collar normally resting upon the operatin arm 35 so as to sustain the rod in a fixed relation thereto. By this means of interconnection between the two operating arms 35 and 69, the upper and lower gates are adapted to be maintained together in substantially vertical positions, as best shown in Fig. 4.
Referring now to Figs. 9-12, both gates remain in their normal positions when the hopper is substantially full (see Fig. 9). In such circumstances the level of the material dumped into the hopper is somewhat above the lower edge of the top gate whereby to exert an outward pressure thereupon. Any inward movement of the gate, or of the lower gate either, is eiTectivel prevented When such a condition exists. As withdrawal of the coalor other loose material proceeds, the level of the pile will descend to the point of freeing the upper gate for inward movement to the point of engagement with the spring 8 (see Fig. 10). When so positioned the operating arm 35 will be spaced from both collars l0 and H. At this stage the lower gate is still prevented from swinging inwardly because the coal level is still sufiiciently high to interfere with any such movement, When the level of the coal pile drops below the lower gate (see Fig. 11), then all interference is removed. At such a time the operating arm will swing down, in response to gravity and tension forces, as far as permitted by the length of the slot 6| whose lower end serves as a stop to limit this movement at a predetermined point,
As the lower gate 55 swings inwardly, its operating arm 80 pulls down the connecting rod 65. This motion brings the upper collar lEl into engagement with the arm 35 whereby to operate the upper gate 3-3 to a further inward position (see Fig. 11). In this last movement the sp ing s is laterally deflected to permit the operating arm 35 to pass. This is the extreme position of the two gates when the pile within the hopper is at the low point. When replenishment starts, the ascending pile will rise past the lower gate 55 to exert thereon a lateral thrust which will force it outwardly to the position of Fig. 12. During this movement, the connecting rod 65 is raised to bring the lower collar 'H into engagement with the operating arm 35. The upper gate 30 is temporarily restrained from swinging outwardly by the spring s whose hook 46 remains engaged with the operating arm 35, Eventually the pile level will rise above the lower edge of the upper gate 30 to force it outwardly, against the resistance of the spring s, to its normal vertical position (see Fig. 9) where its operating arm 35 lies close to the upper collar 10, if not in engagement therewith. At this point the cycle has been completed.
The operating arm 35, as shown, is provided with a high point 15 adapted to engage the lower end of a bar 16 whose upper end bears against one spring arm 1'! cooperating with a second arm 18 of a switch 19 which is interposed in an electrical circuit 80. So long as the upper gate remains in a substantially vertical position, the bar 15 will be maintained in an up position whereby the switch remains open. This open condition of the switch will continue even when the upper gate is swung inwardly through its first stage to the point of engagement with the spring s as indicated in Fig. 10. But when the lower gate also swings inwardly and pulls with it the connecting rod 65 to force the upper gate through its second stage of movement, the operating arm 35 will move out from under the bar 16 which thereupon exerts a down pull on the sprin arm 17 to close the switch 19. This closed condition will continue until the upper gate 30 has started to swing outwardly once more whereupon the switch will automatically open.
The electrical circuit connects with a motor M (see Fig. 1) having a belt drive 8| to a pulley 82 which is afilxed to the shaft [5 within the bunker B. By this means the conveyor is adapted to be operated so lon as the electrical circuit remains closed. The control of this motor is dependent upon the position of the upper gate which, in turn, is influenced by the position of the lower gate, both of the gates being responsive to the level of coal within the hopper. It accordingly results that when the pile level reaches the low stage indicated in Fig. 11, the motor will be energized to start operation of the conveyor whereby to replenish the supply of coal within the hopper. When this replenishment has proceeded to the point that the coal level rises above the lower edge of the upper gate, the latter will be pushed outwardly to operate the switch to open position, thereby cutting off further operation of the conveyor for the time being.
In Fig. 13, there is shown an exactly similar construction applied to a hopper H whose walls 85 are vertical. The control means here employed is identical in that I use interconnected upper and lower gates each of which is so mounted as to be subject to the lateral thrust of the coal pile within the hopper. The parts shown in Fig. 13 are accordingly designated by reference characters the same as those applied to the remaining figures, insofar as there is correspondence. In one minor respect only is there any difference, and that is the normal position of the lower gate 55 which is inclined outwardly at an angle instead of substantially vertical as in Fig. 4. With the coal pile exerting a lateral thrust against the gate, it is free to swing outwardly, as shown, but with suficient depletion of the coal pile this gate will then swing inwardly to the extent permitted by the movement range of its operating arm 60.
The operation of the apparatus whereby to control the switch may be the same as already described.
A primary advantage in the control apparatus herein disclosed lies in the relative infrequency of the operations required for maintenance of an adequate supply of loose material in the hopper. This objective is achieved by employing upper and lower yieldable means so interconnected as to open and close the switch only when th level of the loose material pile falls below and rises opposite the lower and upper yieldable means, respectively. In this interconnection, one of the gates or other yieldable means, either one, has capacity for some lost motion so that the transmission of motion from one to the other is definitely limited. The upper gate is here mounted to swing inwardly through two stages, the first in response to its own biasing and the second in response to motion transmitted from the lower gate. By this expedient, closing of the switch is delayed during descent of the level of loose material until it has dropped below the lower gate. The operating range of the present control is accordingly extended through a rise or descent of the loose material pile level for a very substantial part of the vertical dimension of the hopper, with a consequent reduction in frequency of operations and expenditure of power.
1. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of a pair of vertically spaced swinging gates within the hopper each adapted to yield outwardly in response to lateral pressure from the loose material pile within the hopper, means for swinging each gate inwardly of the hopper when free of pressure from the material pile therewithin, means interconnecting the two gates adapted to transmit an inwardly swinging movement from one to the other, means for controlling operation of the power driven conveyor including an electrical circuit wherein is a switch, and a motion-transmitting connection between the switch and the upper gate operable in response to outward swinging of the latter to actuate the switch whereby to stop operation of the power driven conveyor.
2. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of upper and lower movable means normally maintained in an inward position but independently outwardly yieldable in response to lateral pressure from the loose material pile within the hopper, a limited motion-transmitting connection between the two movable means, means for controlling operation of the power driven conveyor including an elec trical circuit wherein is a switch, and operating means for the switch connected to one of the movable means adapted for actuation thereby in response to inward movement thereof.
3. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of upper and lower movable means within the hopper normally biased to an inward position but yieldable outwardly independently in response to lateral pressure from the loose material pile within the hopper, a limited motion-transmitting connection between the two movable means, means for controllin operation of the power'driv'en conveyor including an electrical circuit wherein is a switch, and means comprised in the limited motiontransmitting connection between the two movable means for operating the switch whereby to start operation of the conveyor power drive when both the upper and lower yieldable means are biased to their inward positions.
4. The combination with a power driven con-.- veyor for moving loose material into a hopper for gravity discharge therefrom, of upper and lower movable means within the hopper normally biased to an inward position but yieldable outwardly independently in response to lateral pressure from the loose material pile within the hopper, a limited motion-transmitting connection between the two movable means, means for controlling operation of the power driven conveyor including an electrical circuit wherein is a switch, and means operable by the upper yieldable means adapted when the latter is pressed to its outward position for operating the switch whereby to stop operation of the conveyor power drive.
5. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of upper and lower movable means within the hopper normally biased to an inward position but yieldable outwardly independently in response to lateral pressure from the loose material pile within the hopper, means interconnecting the two movable means in a manner whereby one is effective to control movement of the other, and means for controlling operation of the power driven conveyor including an electrical circuit wherein is a switch in operative relation to the interconnecting means adapted to be opened and closed thereby for starting and stopping operation of the conveyor power means when the level of the loose material pile falls below and rises opposite the lower and upper movable means, respectively.
6. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of a pair of gates within the hopper each adjacent one wall thereof at relatively high and low points therein, a pivotal suspension mounting for each gate near its top whereby to permit an outwardly swinging movement thereof in response to lateral pressure from the loose material pile within. the hopper, an operating arm extended outwardly from each gate to a point exteriorly of the hopper and exerting on each gate a gravity force such as to swing the same inwardly whenever the material pile level has descended therebelow, means extending between the two arms in pivotal connection with the one below and in limited sliding connection with the one above adapted to prevent movement of one gate relative to the other when in certain positions, means for controlling operation of the power driven conveyor including an electrical circuit wherein is a switch and means extended from one of the gate operating arms for closing the switch when the material pile level has descended below the lower gate and for opening the switch when the material pile level has ascended sufiiciently high to push the upper gate outwardly.
v'7. The combination with a power driven conveyor for moving loose material into a hopper for gravity discharge therefrom, of upper and lower movable means normally biased to an inward position but independently outwardly yield- 7 able in response to lateral pressure from the loose material pile within the hopper, means for controlling inward movement of the upper movable means whereby it is required to proceed through two stages, the first part way in response to its own biasing and the second the remainder in response to motion transmitted from the lower movable means, means for controlling operation of the power driven conveyor including an electrical circuit wherein is a switch, and operating means for the switch in connection with the up- The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,301,978 Schafier Apr. 29, 1919 2,381,505 Lindholm Aug. 7, 1945