Auger for conveying materials such as manure

An improved auger is used for conveying flowable materials, such as liquid and semi-solid manure, through a bed of a container such as a manure spreader and out through a discharge opening. The auger has a shaft with a back end and a front end, a continuous blade, and paddles for discharging the manure. The continuous blade extends radially outwardly from the shaft and includes helical portions and at least one plate portion which is substantially perpendicular to an axis of the auger. The plate portions extend between the helical portions of the blade to make the blade substantially continuous. The rotation of the auger causes helical portions of the blade to accelerate the manure in a direction of the front end wall and causes the plate portions to slow the movement of manure so that the rate of flow of manure is controlled and boiling action of manure against the front end wall of the container is inhibited. Additionally, the rotation causes the plate portions to create turbulence within the manure as it contacts the plates to disrupt bridging of manure over the auger.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates generally to augers which are used for conveying 
materials within an enclosure and particularly to augers used in moving 
liouid or semi-solid manure through the bed of a manure spreader. 
2. Description of the Prior Art 
Manure spreaders utilize various types of mechanisms, including augers, to 
move manure within the body of the spreader to a discharge opening. In 
manure spreaders which use augers to convey manure along the bed of the 
spreader, it is common to find that certain consistencies of manure boil 
up within the spreader container bed, particularly at the end of the 
auger, and may form bridges over the auger. Various designs have been 
addressed to these problems. One type of manure spreader, as shown in U.S. 
Pat. No. 4,467,967 to Martin, has a longitudinally positioned auger with a 
series of separate blades which are arranged in oppositely generated 
helices to urge the manure from the rear and from the front of the manure 
container body toward a discharge gate which is positioned in the body 
between the ends thereof. By moving manure from the ends to the middle 
portion of the body, the auger may eliminate some boil-up that would occur 
at an end wall, but it may not always be advantageous to have the 
discharge opening in the middle portion of the body. The auger shown in 
that patent is also raised and lowered hydraulically to break up bridging 
of manure within this particular spreader. 
Additionally, a variety of augers and screws are currently used to move 
fertilizers, sludge, solid and liquid manure, and other types of materials 
through chutes, tubes, beds, and other containers. U.S. Pat. No. 4,206,841 
to Lundgren discloses a screw conveyor which has a helical blade which 
extends outwardly from the shaft for conveying material along a passage 
from one end to the other with rotation of the screw. A plurality of 
helical blade segments are mounted at one end of the screw, each segment 
extending over an arc of about 100.degree. to about 130.degree. around the 
shaft of the screw. These blade segments split the main flow of material 
from the helix up into several smaller flows, thereby maintaining a 
relatively uniform flow of the conveyed material even when the conveyor is 
filled only to 30% of its flow capacity. The smaller blades at the end of 
the screw are discontinuous, that is, they are not connected to one 
another. 
A screw-driven sludge thickener having a rotary screw extending 
longitudinally in an enclosure is disclosed in U.S. Pat. No. 4,528,098 to 
Treyssac et al. The pitch of the Treyssac screw varies in successive 
stages so that the distance between the flights of the screw varies in the 
different stages. U.S. Pat. No. 3,303,917 to Wilkes et al. discloses a 
material conveying and distributing device having an auger with a helical 
blade which varies in pitch depending upon its relative position on the 
shaft of the auger. 
A particular problem which occurs in manure spreaders with auger feed is 
that with certain consistencies of manures, particularly semi-solid 
manure, the auger may not supply material at a continuous rate to the 
discharge opening, thus creating uneven and sporadic spreading of manure. 
Such inconsistent supply of manure may occur because the auger is rotating 
too slowly and does not convey manure to the discharge opening at a rate 
commensurate with the rate at which manure is drawn from the opening by a 
spreading device mounted at the opening. Conversely, inconsistent 
spreading can occur if the auger is rotating too fast and supplies more 
material to the discharge opening than can be spread by the spreading 
device. The excess material being fed by the auger which cannot be 
discharged is constrained by the sides and end panels of the manure 
spreading container and tends to be pushed upwardly. This action tends to 
compress and pack the material above the auger, resulting in a bridging 
condition in which the packed manure forms a solid mass which bridges over 
the auger. The bridged material thus cannot be fed by the auger to the 
discharge opening, resulting in sporadic discharge or no discharge at all. 
Because the consistency of manure, particularly the semi-solid type, can 
vary greatly from load to load and even within a load, it is not practical 
to attempt to vary the auger speed to match the flow of material from the 
auger with the rate at which material can be spread from the discharge 
opening. While multi-blade augers, such as those described above, have 
been used in an attempt to avoid bridging and provide more continuous flow 
of manure, it is generally preferable that the auger have a continuous 
blade since continuous blades are less susceptible to damage by rocks, 
wood, steel or other foreign materials. Continuous blades also tend to be 
self-cleaning; for example, long fibrous materials, such as hay, do not 
hang up on the continuous flights and clog the path of flow as can happen 
with augers having many separate blades. Because of the self-cleaning 
action of a continuous flight auger, freezing of material on the auger 
during cold weather is also not a problem as it can be with augers having 
multiple blades. 
SUMMARY OF THE INVENTION 
The present invention solves the aforementioned and other problems of the 
prior art, and provides an improved auger which can convey flowable 
materials such as liquid or semi-solid manure through a container at a 
consistent rate. A preferred manure spreader which utilizes the improved 
auger may have a V-shaped bed formed from a pair of end walls, a pair of 
side walls, and a rounded bottom, one of the side walls having a discharge 
opening located near the front end wall of the bed. The improved auger is 
mounted for rotation adjacent the rounded bottom of the bed to deliver 
manure to the discharge opening at a rate which substantially matches the 
rate of discharge from the opening. 
The auger of the invention has a continuous blade which operates to avoid 
bridging of semi-solid manure over the auger and of boiling up of the 
manure. The continuous blade extends radially outwardly from the shaft and 
includes a plurality of helical portions with normal helical pitch and of 
a radius approximately the same as the rounded bottom of the manure 
spreader bed, and a plurality of plate portions which are mounted 
substantially perpendicular to the axis of the auger. These plate portions 
extend between the helical portions of the blade to make the blade 
substantially continuous. Rotation of the auger causes the helical 
portions of the blade to contact the manure and accelerate it toward an 
end wall of the spreader. The plate portions of the blade cause the 
movement of the manure to be controlled to prevent boil up at the end wall 
and serve to inhibit bridging and to maintain a consistent flow rate 
irrespective of the characteristics of the manure in the spreader. 
The ability of the improved auger of the present invention to regulate the 
flow of material may be understood by considering the movement of material 
conveyed by the auger. Material in contact with the helical portions of 
the auger--the auger portions having a relatively high pitch--are moved 
forward as the auger rotates toward the plates, which have a low or zero 
pitch. As this movement occurs, the material must either compress, 
accelerate through the low pitch portions of the auger, or be driven away 
from the auger. Although there may be some compression of the material, 
the reduction in pitch between the helical portions and the plate portions 
is too great to be accommodated solely by compression of the material. The 
more liquid materials tend to accelerate through the low pitch region, 
thus causing turbulence and agitation of the accelerated material and any 
material surrounding the auger. In the more solid types of materials, the 
predominant action is the pushing up of the material into the space above 
the auger, since the auger is adjacent the bottom of the container and 
material can only flow away from the auger substantially upwardly. The 
upward pushing action causes material above the auger to heave and 
undulate, and thereby be sufficiently agitated that it remains in a 
substantially flowable state, helping to avoid solidification of the 
material sufficient to form a bridge over the auger. 
Since only a portion of the material being fed by the auger can pass 
through the low pitch plate areas, a void is created downstream of the 
plate areas where the helical portions again make contact with the manure 
to drive it away from the plates. The material above the auger in the area 
behind the plates then drops or is drawn into the void so formed. As a 
consequence, bridging is further inhibited and the auger is charged with 
material along its entire length rather than just at the end of the auger 
from which feeding begins. 
The plate portions of the blade each have a margin which defines the radial 
height of the plate portion. The radial height of each plate portion where 
it joins a back end of a helical portion is preferably equal to the radial 
height of that helical portion, and may be less elsewhere along the plate 
portion's margin. Such a reduction in radius of the plate portions in 
comparison to the helical portions allows some of the manure to pass 
across the margin of the plate portion of the blade as the manure moves 
toward the front end of the bed. The margin of each blade plate portion 
preferably has a straight edge that chops manure as the auger rotates. The 
auger also preferably has a plurality of paddles which extend tangentially 
outwardly from the shaft near the discharge opening. These paddles each 
have a pushing surface which pushes manure away from the auger and out of 
the bed into the discharge opening. 
Further objects, features and advantages of the invention will be apparent 
from the following detailed description when taken in conjunction with the 
accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
As shown in drawings, the manure spreader 10 of the present invention has 
an improved auger 12 with a continuous blade 14 having helical portions 16 
and plate portions 18. The manure spreader 10 has a V-shaped bed 20 having 
a back end wall 22, a front end wall 24, a pair of side walls 26 and a 
rounded bottom 28. The side walls 26 with the bottom 28 form the bed 20 
into a general V-shape as shown in FIG. 1. One of the side walls 26 has a 
discharge opening 30 therein near the front end wall 24. As best shown in 
FIGS. 2 and 4, the improved auger 12 includes a shaft 32 having a back end 
34 and a front end 36, with the front end of the shaft rotatably mounted 
to the front end wall 24 and the back end of the shaft rotatably mounted 
to the back end wall 22 so that the shaft can rotate about a 
longitudinally aligned axis of rotation. The back end 34 of the shaft 32 
has splines 38 which allow the auger to be engaged by a standard drive 
system well known in the art. 
The continuous blade 14 extends radially outwardly from the shaft 32, and 
includes a plurality of helical portions 16 with radius approximately the 
same as that of the rounded bottom 28 of the bed 20. The blade 14 further 
includes a plurality of plate portions 18 which are perpendicular or 
substantially perpendicular to the axis of the auger 12. These plate 
portions 18 extend between the helical portions 16 of the blade 14 so that 
the blade 14 is substantially continuous. Rotation of the auger 12 causes 
the helical portions 16 of the blade 14 to contact the manure (not shown) 
and to accelerate it in the direction of the front end wall 24. Unchecked, 
this acceleration toward the front end wall 24 would cause the boiling 
action of semi-solid manure which does not pass through the discharge 
opening as the excessive manure flows against the wall 24. However, the 
plate portions 18 control the movement of manure in the direction of the 
front end wall 24 as described above, thereby preventing the boiling up of 
manure against the front end wall 24. Additionally, the plate portions 18 
each create an upward turbulence within the manure as the manure moves 
against a back face 48 of each plate portion 18. This turbulence and the 
voids created behind the plate portions inhibits bridging of semi-solid 
manure over the auger 12. 
The preferred improved auger 12 has the continuous blade 14 mounted to the 
shaft 32 in any suitable way, as by welding. The blade 14 has a series of 
helical portions 16 and connected plate portions 18 going from near the 
back end 34 toward the front end 36 of the shaft 32. These blade portions 
are preferably connected to the shaft and to the adjacent helical portions 
by welding. There are preferably several plate portions 18 separating a 
series of helical portions 16. Satisfactory conveying of various 
consistencies of manures has been obtained with the plate portions 
preferably extending in an arc of about 180.degree. around the shaft and 
the helical portions preferably extending about the shaft in an arc from 
about 180.degree. to 360.degree., although other ranges of arc lengths for 
the helical and plate portions may be utilized as desired. In the 
exemplary auger shown in the drawings, the first helical portion 16 begins 
near the back end 34 of the shaft 32 and winds 180.degree. around the 
shaft 32 where it joins the first plate portion 18. The first plate 
portion 18 circles perpendicularly to the axis 180.degree. around the 
shaft 32 to where it joins with the second helical portion 16. The second 
helical portion 16 winds 270.degree. around the shaft 32 to where it joins 
with the second plate portion. Again, the second plate portion 18 circles 
perpendicularly to the axis about 180.degree. around the shaft 32 to the 
third helical portion 16. The third helical portion 16 winds 360.degree. 
around the shaft 32 to the third plate portion 18. The third plate 18 
circles perpendicularly to the axis 180.degree. around the shaft 32 to the 
fourth helical portion 16. The fourth helical portion winds 360.degree. 
around the shaft to the fourth plate portion 18. The fourth plate portion 
circles perpendicularly to the axis 180.degree. around the shaft 32 to the 
fifth and final helical portion 16 which ends the continuous blade 14. 
While these stated angular measurements disclose the preferred improved 
auger 12, other various combinations of alternating helical portions 16 
and plate portions 18 may be used and be considered an alternate 
embodiment of the present invention. Additionally, the plate portions 18 
may circle less than or greater than 180.degree. around the shaft 32. The 
fifth helical portion 16 at the end 68 of the blade 16 is joined to an end 
fin 70. The end fin 70 is a small plate of metal, which may be tapered as 
shown, which extends perpendicularly out from the shaft and is joined to 
the front end 68 of the blade 16 to reinforce the end of the blade. 
As is best shown in FIG. 3, the plate portions 18 of the blade 14 each have 
a margin 72 which defines the radial height of the plate portion. Where a 
plate portion 18 joins a back end 74 of a helical portion 16, the radial 
height of the plate portion 18 is preferably equal to the radial height of 
the helical portion 16. However, elsewhere along its margin 72, the radial 
height of the plate portion 18 is preferably somewhat less than that of 
the helical portion 16. Since the radial height of much of the plate 
portion 18 in such a case is less than that of the helical portions 16, 
some manure will pass across the margin 72 of the plate portion 18 of the 
blade 14 as the manure moves in the direction of the front end wall 24. 
The plate portions 18 of the preferred auger 12 have, along the margin 72 
of each plate portion 18, four straight edges 76 which chop the manure as 
the auger 12 rotates. Although the preferred auger 12 has plate portions 
18 with four straight edges 76, alternate embodiments of the improved 
auger 12 may have plate portions 18 with any number of straight edges for 
chopping manure which passes over or under the plate portion as the auger 
18 rotates. It is also preferred that the plate portions 18 be flat and 
mounted with the plane of each plate perpendicular to the axis of rotation 
of the auger. However, the plates may also be formed as slight helices, 
having a few degrees of pitch, which interconnect the normal pitch helical 
portions. Plates with a slight pitch rather than zero pitch will also 
serve to reduce the speed at which manure is propelled by the auger as 
well as to provide the agitating action which aids in preventing bridging. 
As shown in FIGS. 2 and 4, a plurality of paddles 46 extend tangentially 
outwardly from the shaft 32 near the location of the discharge opening 30. 
Each paddle 46 has a pushing surface 78 which pushes manure out the 
discharge opening 30 as the auger 12 rotates. The preferred auger 12 has 
five paddles 46 which proceed in a series in a frontward direction along 
the shaft 32. The paddles 46 are placed along the shaft 32 so that each 
paddle 46 is spaced axially equidistant from the adjacent paddles 46 and 
also 90.degree. circumferentially from the adjacent paddles 46. Since each 
paddle 46 is spaced circumferentially 90.degree. from its adjacent paddle 
46, the fifth paddle 46, which is the front-most paddle, is therefore 
circumferentially aligned with the first or back-most paddle 46. Alternate 
embodiments of the present invention may vary the number of paddles 46 and 
the spacing between adjacent paddles 46. In the preferred auger 12, each 
paddle 46 further includes a stiff brace 84 which extends between the 
shaft 32 and a face 86 of the paddle 46 opposite the pushing surface 78. 
Alternatively, the auger may have paddles 46 which are pivotally joined to 
the shaft 32. In such an embodiment, each paddle additionally includes a 
spring (not shown) which extends between the shaft 32 and the face 86 of 
the paddle opposite the pushing surface 78. This spring maintains the 
paddle pushing surface 78 generally in tangential relation to the shaft 
32, and compresses to allow the paddle 46 to pivotally give way to any 
substantial impediments in the path of the paddle 46 which might damage 
the paddle 46. After passing over the impediment, the paddle 46 is pushed 
by the spring back into its normal tangential position in relation to the 
shaft 32. 
In operation, the manure spreader 10 with improved auger 12 serves as an 
effective means for spreading all consistencies of manure on a field. 
After the bed 20 of the manure spreader 10 has been filled with manure, 
the manure spreader 10 may be operated by rotating the auger 12 by its end 
36 by means of a standard drive system. As the auger 12 turns, the helical 
portions 16 of the blade 14 come into contact with adjacent portions of 
manure and accelerate them through the passageway formed between separate 
flights of the blade 14. When a portion of manure is in the passageway 
adjacent to the helical portions 16, the manure accelerates in the general 
direction of the front end wall 24. Then when that portion of the manure 
moves through the passageway, so that it is forced against a back face 48 
of a plate portion 18, the manure slows down. This slow-down creates an 
upward turbulence in the manure which breaks down and prevents the 
formation of any bridging over the auger 12. The void formed behind the 
plates draws manure from above down into the auger. Additionally, the 
progressive acceleration and slowing down of the manure as it moves along 
the passageway causes the manure to move in the general direction of the 
front end wall 24 at a controlled, consistent pace. 
After exiting the fifth helical portion 16, the manure comes into contact 
with the paddles 46 which are located on the shaft 32 nearby the discharge 
opening 30. As the auger 12 turns, the pushing surface 78 of each paddle 
46 ejects the manure it contacts out of the discharge opening 30. In this 
manner, the improved auger 12 empties the bed 20 of substantially all 
manure, whether liquid or semi-solid. The present invention is 
advantageous in that it does not require a separate auger or hydraulic 
lifting of the auger preventing the buildup of bridging over the auger. 
It is understood that the invention is not limited to the particular 
embodiment disclosed herein as illustrative, but embraces much modified 
forms thereof as come within the scope of the following claims.