US 2055139 A
Description (OCR text may contain errors)
Sept. 22, 1936. vf ANDREWS FEDING MECHANISM Filed nec. s, 193s 2 Sheets-Sheet 1 K lll/11111111111111111111 sept.22,1936. L. v; ANDREWS 2,055,139
FEEDING MECHANISM Filed Dec. 8, 193s 2 sheets-'sheet 2 Patented Sept. 22, 1936 UNITED STATES 'PATENT oI-Fics- Stoker Corporation, ration of Massachuset Wtzroeatcr, Macs., a corpo Appunti@ December s, issasenn No. ramas 1 claim. (ci. 19a-sn This invention relates to feeding mechanisms, and more particularly to mechanisms of the type comprising a substantially horizontal trough which is vibrated to produce a feed of material along the trough. v
`It is one object of the invention to provide a simplied construction .for a feeding mechanism of the vibrating trough type, to reduce the cost of manufacture, and to ensure 'continuous and reliable operation.
It is a further object of the invention to combine with the vibrating trough a means for supplying material thereto continuously and without danger of interruption in normal operation. and particularly to so arrange the Vconstruction that if a large piece of material should block the feed it can be readily removed.
It is a further object of the invention to com-` bine with the vibrating trough a material supply means which can be easily adjusted to permit operation of the feeding mechanism at maximum capacity with materials of widely different char-V acteristics. l l
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specication and covered by the'claim appended thereto.
Referring to the drawings illustrating' one embodiment of the invention, and in which like reference numerals indicate like parts,
Fig. i is a. vertical longitudinal section through a feeding mechanism, the section being taken on the line i--S of Fig. 2; l
Fig. 2 is a section on the-iine 2-2 of Fig. i;
Fig. 3 is a section on the line 3 3 of Fig. 1;
Fig. t is an enlarged view in 'section showing the rear portion of the vibrating trough;
Fig. 5 is a side yelevation of the vibrating trough with the supporting and driving means therefor;
Fig. 6 is a rear elevation of the parts shown in Fig. 5;
Fig. 7 is a top plan view of the rear portion of the construction shown in Fig. 5 with the magnet protecting cover removed: and
Fig. S is a perspectivey view of the rear portion of the vibrating trough.
In the drawings I have shown a feeding mechanism'comprising an elongated base I0 provided with three transverse ribs il on its upper surface.
Three upwardly and rearwardly inclined thin fiat springs i2 are fastened at their lower ends to the ribs Il by. means of screws i4. The upper ends of the springs I2 are fastened by means of screws it to transverse ribs I6 formed on the bottom of a horizontal trough il. The springs form the sole support for the trough, which is free to vibrate in a generally longitudinal direction. The trough is preferably constructed of a comparatively light material, such as aluminum, in order to facilitate the vibrating action.
In order to vibrate the trough i8 I utilize an electro-magnet, and since aluminum is non-magnetic it is necessary toprovide a suitable pole piece. .For this purpose I form a transverse groove I! in the rear'end of the trough,' and Ig insert in this groove a pole piece 20 which is preferably made of a large number oi thin horizontal strips or laminations of iron. These laminations are held iilrmlyA in place by means of rivets 2i extendingvertically through the pole piece andthe adjacent portions of the trough.
Directly in the rear of the pole piece is .a
stationary electro-magnet comprising a core 23 of laminated iron shaped as a letter E with the branches of the E pointed toward the pole piece. The magnet is energized by means of a coil 24 surrounding the central branch of the E` and held in place by a strap 25. The core 23 is secured to a bracket 21 which is fastened to the rear portion of the base III) by means of screws 28. These screws extend through slots 29 in the bracket so that the bracket can be adjusted longitudinally of the base to vary the width of the air gap 30 between the magnet and the pole piece. l
If particles of material should become lodged in the air gap $0 they would interfere with the vibration of the trough. In order to avoid this dimculty, I provide a protecting cover plate in the form of a hood 32 fastened to the rear end of the trough i8 and extending rearwardly over the top of the magnet. The hood is shaped as an inverted U, as shown in Fig. 6, and extends downwardly at each side of the magnet. It will be apparent that this hood renders it practically impossible for material from the trough to reach the air gap 3|).
My improved feeding mechanism is arranged to deliver material to a chute 34 (Fig. 1) and for this purpose the mechanism is mounted in acasing 35 with the front or discharge end of the trough i8 projecting over the chute. The base I0 is preferably provided with four rubber feet 36 which rest in suitable recesses in the bottom` wall of the casing 35, thus supporting the feeding mechanism in the proper position. The casing is closed at the rear by a vertical plate 3l which can be removed to permit withdrawal of the feeding mechanism.
, and a second side wall 45- which is substantially vertical. The use of the vertical wall 45, inconjunction with the action of the trough in vibrating the mass of material directly beneath the hopper,
is decidedly effective in preventing the materialA from arching in the hopper and thereby obstructing the feed.
'I'he vertical distance between the troughl I3 and the lower edge of the front wall 43 of the hopper determines the thickness of the stream of material flowing along the trough to the chute 34,
and I have discovered that for any given material there is a. definite value for this distance which will provide the maximum feeding capacity. If the distance 'is either decreased or increased with respect to the said definite value, the feeding capacity will be reduced. Moreover the vertical distance which will result in maximum capacity varies with the type of material being fed, with its neness, and with its moisture content. In order to make possible high capacity operation with widely differing materials, I provide means for varying the aforesaid vertical distance as may be desired. This is accomplished in the embodiment illustrated by providing a plate 41 which is secured to the wall 43 by means of a thumb screw 48 extending through a slot 49 in the plate. This plate projects below the wall 43 and in eiect forms a downward extension of this wall which can be readily adjusted vertically. In order tois provided with a transparent panel 52 through' which the feed of the material may be observed. In 'case al foreign body or a block of material reaches the 'trough I8 which is too large to pass beneath the plate 41', the plate may be raised and provided by the removal of the closure 5I. The rear wall' 42 of the hopper is preferably provided with an opening 54 for the insertion of a suitable bar or poker to assist in the removal of a possible obstruction.
In order to prevent spilling of material over the sides of the trough, a skirt or apron 561s provided which in eiect forms a downward extension of` the two side walls and the rear wallvof the hopper. This skirt is preferably formed of thin sheet metal, such as brass, which is smooth and noncorrosive, so that material will not adhere thereto. The skirt extends downwardly into the trough without touching the same, and it is supported by a horizontal flange 51 at its top which is clamped between the casing 35 and the hopper 40. It will be noted from Fig. 1 that the'skirt 56 extends forwardly at each side of the trough for a substantial distance beyond the front wall 43 of the hopper, and in fact nearly to the front end of the trough. This .makes it possible to maintain a thick mass of material in the trough without spilling, and yet the sides of the trough need not be very high.
' Hence the trough can be made comparatively light, which is an advantage in a vibrating type of feeder.
It will be apparent that the feeding mechanism 'can be withdrawn rearwardly from the casing 35 a closure for thebottom of the hopper, and for v this purpose I utilize the plate 31. The hopper is formed with grooves 59 at each side directly above the skirt 56, and the plate 31 may be removed from its normal position and thereupon inserted horizontally into these grooves from the rear.
The operation of the invention will now be ap-l parent from the above disclosure. Thel coil.24 is supplied with a suitable electric current, such as 60 cycle alternating current, which will produce a rapid pulsation in the magnetic flux in the core 23. This will attract and release the pole piece 20 'in rapid succession, so that the trough I8 will vibratey in a generally longitudinal-direction under the combined iniuence of the'springs I2 and the ielectro-magnet. Material is delivered to the hopper 4I) by the downspout 39, and after descending by gravity-into the trough I8 the material is .carried along by the vibrating action and deposited in the chute 34. 'Ihe conveying of the material horizontally is believed to be due in part to the angular arrangement of the springs, which causes the forward movements of the trough to be slightly upward toward the material, and the rearward movements to be slightly downward and away from the material. The action is also believed to be due in part to the fact that the rearward movements of the trough are more rapid than the. forward movements, since the rearward movements are brought about by the combined forces of the springs and the electro-magnet, whereas the forward movementsl are brought about by' the springsA alone. The inertia of the material being fed apparently prevents it from following the rapid rearward trough movements while allowing lt to follow the slower forward movements. Whatever may be the correct theory of operation, it is known that the material will advance toward the chute 34 as the trough is vibrated..
The plate 41 can be adjusted to the height which-is found by experiment to produce the maximum rate of feed fo'r the particular material being handled. Thereafter the feeding rate can be reducedif desired by controlling the current flow through the coil 24 in any well-known manner, thus controlling the amplitude of vibration of the trough. In case thefeed is obstructed by a large body, the plate 41 can be easily raised or removed to permit withdrawal of the obstruction.
Since the side wall 45 of the hopper is vertical, the material is not held thereagainst by gravity but passes directly downward under the combined action of its weight and the vibration imparted to it by the trough. This prevents any arching of the material between the walls 44 and 45, regardless of the close spacing of these walls, for an arch requires a supporting abutment at each end. The walls 42 and 43 are spaced a considerable distance apart, so thatlittle opportunity is aiorded for arching between them. The smooth skirt 56 directs the material into the trough without spillage, and the hood 32 prevents any possibility of particles of material reaching the air gap 33. 'I'he arrangement of the electro-magnet at the rear of the trough and the means for mounting the pole piece in the rear portion of the trough combine to produce a very simple, rugged an`d inexpensive construction.
Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:
A feeding mechanism comprising a substantial- 1y horizontal trough, means to vibrate the trough and produce a feed ot material along the trough toward the front end thereof, a casing enclosing the trough laterally, a hopper supported Vby the 5 casing and arranged tosupply material to the.
trough, and a skirt extending downwardly into the trough from the rear wall and the two side walls of the hopper to prevent spilling of material, the skirt having a horizontal ange at its upper edge which is clamped between the casing and the hopper.
L. V. ANDREWS.