Lip vibrator unloader

A vibrator feeder for causing piled up granular material to move down its own slope and off the edge of a shelf-like structure for unloading. The vibration is limited to material resting on a small edge, or lip, of the material support structure. This lip is formed as an extension of the floor of the bin. A series of rods supported from a vibration generator extend into the material resting on the lip. The vibrations disturb the angle of the repose of the material which feeds off the lip.

SUMMARY OF THE INVENTION 
This invention deals generally with conveyors and more specifically with a 
gravity conveyor system which uses a vibrating means to affect the flow of 
material. 
The use of vibration producing mechanisms in conveyor systems is well 
established. They are used in several ways. One is the essential motive 
means for conveyors, in that the material is moved essentially by the 
vibration of a slightly sloped conveyor. Another use is as an auxilliary 
device in a hopper, where vibration is used to keep the material from 
forming a bridge. Vibration is also used as an unloading aid for hoppers, 
where vibration of the hopper or bin encourages the material to continue 
when its angle of repose would normally prevent flow. 
This latter use is addressed in the present invention. This approach to 
unloading bins has not received the use it might have because the power 
required to produce the vibratory motion has been so great. In a 
conventional system the power required is largely dependent on the weight 
and height of the material stored, and therefore usually requires 
exceptionally large motors and power sources. In order to have, for 
instance, wheat flow out of an opening at the bottom of a side of a 
hopper, it has been necessary to vibrate the whole bottom plate of the 
hopper. Since the entire load of wheat is resting on this plate, it, 
understandably, requires a great deal of motive force. 
The present invention dramatically reduces the power required to cause 
material flow in such a situation. This is accomplished by constructing a 
shelf in the nature of a false bottom, under the edge of the hopper where 
the side opening is located. For instance, in a rectangular shaped bin 
with an opening at the bottom of one side, this secondary shelf parallels 
the opening, and extends both under the actual hopper bottom and somewhat 
beyond the plane of the open-bottomed side. The stored material thus 
spills out onto the secondary shelf with its normal angle of repose. The 
secondary shelf, however, supports only the small amount of spillage, and 
not the weight of the entire hopper. The extension of the seconary shelf 
beyond the bottom plate is adjusted to closely match the length of the 
spillage of the material, as determined by the size of the hopper opening 
and the angle of repose of the material, so that, when the system is at 
rest, the material spills just to the edge of the secondary shelf. 
Thus, when the secondary shelf is vibrated the material feeds off the lip 
of the shelf onto, for instance, another conveyor or a waiting vehicle. 
Since the secondary shelf supports only a very limited amount of the 
material, the power required to vibrate it is minimal compared to the 
power required for conventional vibrator unloaders. Moreover, the minimal 
weight drastically reduces the size of the structure required to support 
the material to be vibrated and thus the power required is reduced even 
further. Similarly, the cost of the support structure is dramatically 
reduced. 
An alternate embodiment of the invention uses vibrating rods emplaced 
within the spillage on the bin bottom plate. These rods function as does 
the secondary shelf, but in this case not even the weight of the shelf 
need be vibrated, and the power used is even further reduced. In this 
embodiment the bottom of the bin is itself extended just beyond the point 
to which the spillage from the opening extends. A series of rods is 
located near the edge of the bottom and extending close enough to the 
bottom plate to be immersed in the material, so that, when these rods are 
vibrated, they affect the angle of repose of the material sufficiently to 
cause the material to flow over the lip of the bottom plate. 
The result of the present invention is a vibrator type unloader which 
performs the same job as prior art unloaders, but does so with far less 
initial cost because of the simplicity of the structure and much less 
power consumption.

DETAILED DESCRIPTION OF THE INVENTION 
The preferred embodiment of the invention is shown in FIG. 1 in which lip 
vibrator 10 is shown installed in association with straight sided bin 12 
supported on legs 13. Bin 12 is constructed with opening 14 in side 16, 
through which material 18 spills in sloped pile 20. Gate 22, adjustably 
attached to side 16 by bolts 24, is used to control the distance sloped 
pile 20 progresses along plate 26 and how closely it approaches lip 28. 
Ideally pile 20 should be set to just approach lip 28, but not spill over. 
Shelf 26 is resiliently supported from bin bottom plate 30 by hangers which 
may be any conventional resilient support, such as springs 32 and which 
permit vibration of shelf 26 with minimal transfer of vibration to bottom 
plate 30. Shelf 26 is vibrated by motor 34 driving vibration generator 36 
coupled to shelf 26 by rod 38. 
As shelf 26 is vibrated, motion is induced in the top surface of pile 20 
which causes the material to progress over lip 28 in direction A. Material 
18 can thus be loaded into a vehicle or onto another conveyor (not shown) 
and the unloading process can be controlled by activating motor 34 with a 
conventional controller (not shown). 
The clear benefit of the invention as shown is that the only material that 
is actually subject to vibration is the small amount in pile 20. The 
weight that must be moved by the vibrating mechanism is, therefore, very 
small compared particularly to the weight that would be moved if bottom 
plate 30 were vibrated. The reduced weight which is vibrated dramatically 
reduces both the power required by motor 34 to activate the vibrator, and 
the strength of springs 32 required to support shelf 26. 
An alternate embodiment of the invention is shown in FIG. 2 in which 
vibrating rod assembly 40, attached to material bin 42, creates the 
disturbance within material pile 44 to cause the upper layer of pile 44 to 
move downward and over lip 46 in direction B. In this embodiment, bin 42 
is constructed as in the previous embodiment, with an opening at the 
bottom of side 48, but spillage support shelf 50 is an integral part of 
bin bottom 52. Material pile 44 therefore extends onto shelf 50, but rests 
there undisturbed until motor 54 is turned on to activate vibration 
generator 56 causing rods 58, whose ends are buried within material pile 
44, to vibrate. The quantity of rods 58, their spacing and location and 
the intensity of their motion, is selected to induce agitation over the 
entire surface of material pile 44. This causes a general flow of the 
material over lip 46 in path B and the material that is thereby unloaded 
is replaced by other material flowing out of bin 42, which then also flows 
over lip 46, providing the vibration continues. 
A controlled bin unloading action therefore results which uses very little 
more power than is required to vibrate the rods alone. While the power 
required does vary with the weight and friction factor of the material it 
is also controllable by the proximity of rods 58 to lip 46, and in all 
cases is far less than the power which would be required to vibrate any 
part of bin 42 along with the weight of material supported. 
A further advantage of this vibrating rod embodiment is that no material 
support structure at all is required to be vibrated, thereby eliminating 
any need for a resilient support on a structural member. Moreover, the 
inherently simple construction of this embodiment permits its addition to 
existing bins with minimal difficulty. 
It is to be understood that the form of this invention as shown is merely a 
preferred embodiment. Various changes may be made in the function and 
arrangement of parts; equivalent means may be substituted for those 
illustrated and described; and certain features may be used independently 
from others without departing from the spirit and scope of the invention 
as defined in the following claims. 
For instance, the vibrating rod embodiment can also be constructed upon a 
bin with an adjustable gate as in FIG. 1, and the invention can also be 
used with hopper type bins by construction of a horizontal vibrating shelf 
below their opening. Moreover the shelf or vibrating rod assembly need not 
be attached to the bin but can be independently supported.