Material chopping apparatus

An improved tub chopper is disclosed having a speed sensing device which automatically slows the tub sidewall speed responsive to slugging or slowing of the chopping apparatus. A positive drive to the tub sidewall is provided by means of an economically constructed undulated band secured to the sidewall and operable through a plurality of rollers on a rotating wheel to drive the sidewall. The tub floor is configured with an upwardly convex, gradually tapering shape terminating in an adjustable wing extension for enhancing the movement of material in the tub into the chopping station. Novel chopping knife construction maximizes the effective life of the chopping knives. One knife embodiment presents six different available cutting surfaces and another embodiment involves disc shaped knives wherein the entire disc periphery is utilized for cutting material. The discs are continually rotated to change the portion of the cutting edge which is in material cutting position.

This invention relates to material comminution apparatus, and more 
particularly to improvements in apparatus for grinding or chopping 
material such as animal feed crops or the like. 
In my co-pending application Ser. No. 229,347 filed Jan. 29, 1981, now U.S. 
Pat. No. 4,364,526 I disclose an improved tub grinding or chopping 
apparatus. The present application pertains to certain improvements which 
can be used in association with the apparatus disclosed in said earlier 
application, which disclosure is incorporated herein by reference. The 
improvements of this invention may also be useful with other types of 
apparatus. 
One significant problem confronting the users of all kinds of comminuting 
equipment is the rapid rate at which the material cutting knives become 
worn or dull. Typically the chopping action is carried out by means of a 
rapidly rotating drum or wheel which carries a plurality of knives moving 
on a path of travel to engage and sever the material to be processed by 
the apparatus. Often such material is hay, fodder, straw or other crop 
material which has a tendency to wear the sharpened knife edges until they 
are dull and no longer well suited for severing the material. When this 
occurs, the horsepower requirements for operating the machine rise 
substantially and the quality of the chopping action deteriorates into 
more of a shredding or tearing action than is ordinarily desired. 
Until now, it has generally been necessary for the machine operator to 
change out the worn knives, replacing them with new sharpened knives, 
after they have become dull. This represents a substantial cost to the 
user of the machine, the allevation of which can materially improve the 
efficiency of the overall operation. 
Accordingly, it is a primary object of the present invention to provide a 
new type of knife and knife holder for apparatus of this type and which is 
designed to increase the period of useful life from a set of such knives 
before they must be discarded and replaced. 
In the accomplishment of the foregoing object, it is another object of the 
instant invention to provide a novel knife construction wherein a 
plurality of sharpened cutting edges are provided around the periphery of 
the knife, the knife holder being adapted for manipulation in a manner to 
quickly move the dulled edge from its cutting position and the movement of 
a sharp edge into its place. 
A further object of the invention is to provide such a knife wherein the 
advantages mentioned above can be utilized with any of a wide variety of 
cutting devices such as sickle bar mowers, harvesters and the like. 
Still another important object of the present invention, attainable with 
one embodiment of the invention, is to provide such knives wherein the 
entire periphery of each knife is sharpened and the knives are mounted in 
a manner wherein the portion of the sharpened edge presented for cutting 
the material is continuously and automatically changed during the cutting 
operation, thereby insuring maximum life for the knives and minimizing 
down time for knife replacement. 
Another object of the present invention is to provide in a tub chopper of 
this type, an improved floor construction to insure that the material is 
fed evenly an uniformly to the cutting or grinding apparatus for optimum 
results. The novel floor construction insures that the material in the tub 
does not tend to "bridge" the cutting apparatus and cause stoppages in the 
uniform feeding of material through the machine. 
Still a further object of the present invention is to provide in such a 
machine an improved grid structure associated with the rotary chopping 
apparatus to enhance the chopping operation and to resist the possibility 
for relatively long strands of material to enter the discharge conveyor 
before they have been properly reduced to the appropriate size. 
It is another object of the present invention to provide a tub chopper of 
the type disclosed having an automatic speed control operable to reduce 
the speed of rotation of the tub sidewall responsive to reductions in the 
rotary speed of the comminutor device in order to reduce the rate at which 
material is fed to the comminutor during periods when it is fully loaded, 
thereby minimizing any tendency for the apparatus to "slug" or become 
overloaded. 
A further object of the present invention is to provide a positive drive 
for the tub sidewall which drive is relatively economical to fabricate yet 
which obviates any tendency for slippage to occur during sidewall rotation 
.

Referring initially to FIGS. 1 and 2, apparatus embodying the principals of 
this invention is broadly designated by the reference numeral 10 and 
includes a tub 12 mounted on a frame 14 which is, in turn, carried by 
wheels 16 and 18 for transport as may be required. Tub 12 comprises a 
stationary floor 20 carried by frame 14 at an angle with respect to 
horizontal, and a cylindrical tub side wall 22 mounted for rotation on the 
frame. A hydraulicly operated loading apparatus 24 is removably attached 
to frame 14 and projects laterally from the apparatus 10 for loading 
material such as round cylindrical bales of hay, straw, fodder or the like 
into the tub for comminution by apparatus 10 as may be required. Apparatus 
24 is provided as an optional attachment and apparatus 10 can be loaded 
manually if desired. 
Apparatus 10 is normally attached to a prime mover such as a farm tractor 
or the like and power for operating apparatus 10 is provided from the 
prime mover through a main power shaft 26. The power from shaft 26 is 
transmitted through a belt drive 28 to a shaft 30 for turning a rotary 
comminuting device broadly designated 32. Device 32 may be of any suitable 
configuration such as is conventionally employed in a hammer mill or the 
like. It has been found that the comminution of animal feeds such as hay, 
straw, fodder and similar materials can be advantageously effected with a 
chopping action rather than grinding which is conventionally accomplished 
with a hammer mill. For this reason, device 32 which is illustrated in the 
drawing comprises a chopper including a wheel 34 having a plurality of 
knife assemblies 36 secured to the wheel and projecting radially outwardly 
therefrom for engaging material in tub 12 as the wheel is rotated about 
the longitudinal axes of shaft 30. Tub floor 20 has an opening 38 
positioned to permit the projection of device 32 into the tub interior so 
that the knives of the device can engage the material as the latter is 
moved past the device by the rotation of tub sidewall 22. 
A portion of the power from shaft 26 is transmitted through a drive 40 and 
transmission 42 to a gear 44 for rotating the cylindrical sidewall 22 of 
the tub about its axis. A transversely circular rail 46 extends 
circumferentially around sidewall 22 and is complementally received within 
an arcuate groove 48 (FIG. 3) comprising an integral part of gear 44 so 
that rail 46 and gear 44 cooperate to hold the sidewall in its proper 
position above floor 20 and permit rotation of the sidewall about its 
axis. A grooved wheel 50 and a similar wheel 52 are also carried by frame 
14 and all of the grooved wheels are disposed in circumferentially spaced 
relationship around the tub and cooperate with track 46 to mount sidewall 
20 for rotation. 
An elongated rigid band 54 extends around the outer surface of side wall 22 
in concentric relationship thereto immediately beneath rail 46 as 
illustrated best in FIG. 3. Band 54 is rigidly secured to sidewall 22 by 
welding or other suitable fastening means and it is formed from an 
elongated transversely rectangular strip of steel which has been subjected 
to a bending operation to present a continuous series of regular 
undulations 56 at spaced apart intervals along the band in the manner 
illustrated. Gear 44 has a number of downwardly projecting stub shafts 58, 
each spaced around the perimeter of the gear as illustrated in FIG. 5. 
Each shaft 58 journalls a roller 60 of an appropriate size and located for 
operably cooperating with the undulations of band 54 so that the rollers 
engage the band to impart power to tub sidewall 22 for rotating the latter 
during operation of apparatus 10. 
It should be pointed out at this juncture that substantial economies can be 
effected in the manufacture of band 54 by the bending of an initially flat 
strip of steel into the appropriate undulated form. This obviates the 
expense which would be incurred in fabricating a large diameter toothed 
gear as is conventional in constructions of this kind. Further, the use of 
the spaced apart rollers mounted on gear 44 for driving the sidewall 
through the undulated band accommodates for minor variations in the 
regularity of the undulations, further achieving economies over what would 
be involved in the use of conventional cog and gear construction. It has 
been found that this construction serves very well for of rotating 
sidewall 22 during operation of apparatus 10 and the cost of fabrication 
of the components is a mere fraction of that which would be involved with 
machined tooth and gear construction. 
One disadvantage heretofore encountered with tub choppers or grinders of 
the type contemplated by this invention is that round bales of material in 
the tub do not uniformly contact the rotating chopping or grinding 
apparatus. The knives or other comminuting devices project furthest into 
the tub immediately above the axis of rotation of the device. Accordingly, 
a deeper bite is taken from the material at this location than is taken 
from the material located either toward the center of the tub or toward 
the extreme outer margin of the latter. As a result, large bales of 
material sometimes are cut by the device in a manner which forms a 
concavity in the underside of the bale. This retards against uniform 
processing of the material through the apparatus. Bales having a length 
approximately the diameter of the tub are particularly difficult to 
process for this reason. 
Applicant has found that the problems associated with the phenomenon just 
described can be aleviated by a novel configuration of the tub floor 
contour. This contour enhances uniform movement of material to the 
chopping assembly. The improved floor configuration is provided by means 
of a transversely arcuate, convex floor portion 62, illustrated best in 
FIGS. 11 and 12. This arcuate floor portion begins to arise from the floor 
at a location approximately 180.degree. upstream from the comminution 
device 32 and tapers generally uniformly upwardly with a gradually 
decreasing radius of curvature until the portion terminates at device 32. 
In addition, the outermost edge of this arcuate portion generally 
coincides with the outer edge of the tub where the portion begins and it 
decreases gradually as the comminuting device 32 is approached. This is 
indicated in FIG. 2 of the drawing by the line 64 which represents the 
outer edge of this arcuate portion. 
The final quarter of the convex floor surface is formed as a separate 
section or wing 66 hingedly secured to the remainder of the floor by an 
elongated hinge 68 extending approximately one half of the distance across 
the floor as illustrated in FIG. 2. At its terminal end, wing 66 has a 
cross-sectional configuration generally conforming to a peripheral edge of 
the rotatable cutting device 32 defined by the path of travel of the 
cutter knives. 
Wing 66 is operably coupled with a rotatable fore and aft extending shaft 
70 having a handle 72 so that rotation of the shaft by the handle lifts or 
lowers wing 66 about hinge 68 to raise or lower the terminal edge of the 
wing. Thus, the wing serves as a guage so that material in the tub sliding 
along the wing is exposed to the depth at the chopping station as may be 
desired by the operator. The convex floor surface tapered in the manner 
described tends to eliminate undesirable bridging and facilitates movement 
of the bale in a manner to produce even and uniform presentation of the 
material to the comminuting device. The undersurface of the bale tends to 
be supported substantially uniformly by the contoured floor after the bale 
has been exposed to the cutting action, thereby minimizing the tendency 
for a bale to move in a manner that it is not returned to contact with the 
cutting device as it moves around the tub floor. 
The tub sidewall rotates in a clockwise direction as viewed in FIG. 2 for 
normal operation of the machine action. Occasionally, it may be desired to 
reverse the movement of the tub sidewall. For this purpose, the tub floor 
is provided with a small integral convex region 74 on the opposite side of 
opening 28 from wing 66. Region 74 serves to gently elevate material 
moving in a counterclockwise direction as viewed in FIG. 2 as the material 
slides into engagement with the rotating device 32. 
Referring particularly to FIG. 13, it may be seen that floor 20 has a 
downwardly extending slanting portion 74 immediately upstream from device 
32. Wing 66 is provided with a depending portion 76 configured to 
complementally over is this portion 76. Portion 76 serves to prevent long 
strands of material from being drawn into the cutting chamber without 
having first having had sufficient exposure to the cutting knives to cut 
the strands into smaller sections. If not properly cut, the long strands 
tend to overload the cutting device and choke the machine. In other words, 
portion 76 guides the material to the zone of exposure to the knives to 
insure that the material is chopped thereby. 
It has been found to be particularly important to insure that the edge of 
the material guide immediately upstream of the cutting device is projected 
down below the general plane of the tub floor in order to accomplish 
uniform chopping of the material and to prevent the tendency of the 
machine to be slugged or overloaded during the chopping operation. 
Material resting on the support provided by the floor is moved at a 
greater lineal speed proximal the tub sidewall than near the tub axis. It 
has been discovered that there is a tendency for a substantially larger 
amount of material to be drawn down into the cavity around the cutter 
device or wheel at the outermost extremity thereof than elsewhere along 
the wheel. Thus, the wing 66, and more particularly the arcuate terminal 
edge thereof immediately upstream from the cutter device, is extended well 
below the level of material support defined by floor 20. This extension 
permits control of the amount of exposure of the cutter to the cutting 
wheel even well below the floor level in the region at the outer extremity 
of device 32. Such control below the level at which the material in the 
tub is supported has been found critical for smooth, anti-clogging 
operation of the apparatus. 
For best results the wing or deflector in this region should extend in 
general conformity to the curved periphery of the cutter wheel or device 
32 substantially below the floor and preferably from at least four inches 
to about twelve inches below floor level. Good results have been obtained 
by extending this portion of the wing or deflector gauge downwardly to 
about the level of the axis of rotation of the wheel as is illustrated in 
FIG. 13. The extension below the general level of the material support 
should subtend an arc of about ten to twenty degrees of the circle defined 
by the cutter periphery. 
Another feature of apparatus 10 designed to minimize or eliminate slugging 
or overloading of the power source is the provision of speed control 
apparatus designated by the reference numeral 78. Apparatus 78 includes 
structure for reducing the force transmitted to the tub sidewall 22 to 
slow the speed of rotation of the latter responsive to reduction in the 
speed of rotation of the power source. Thus, if the comminution device 32 
becomes overloaded or slugged with material to the extent that the 
rotating speed of the power source is diminished, apparatus 78 effectively 
reduces the speed of rotation that tub sidewall 72 to diminish the feed of 
material to the comminution device until the normal speed of rotation of 
the latter is resumed. Apparatus 78 includes a sheave 80 operably coupled 
to a main power drive for apparatus 10. A speed responsive device 82 
includes a housing 84 rigidly secured to sheave 80 for rotation therewith. 
A pair of opposed crank arms 86 are pivotly coupled to housing 84 and have 
weights 88 on the outermost legs of the cranks so that the arms 86 tend to 
be moved outwardly under the influence of centrifical force as housing 84 
is rotated. Such pivotal movement of cranks 86 cause a plunger 90 to be 
shifted in a direction to elongate spring 92 as will be readily understood 
by those skilled in the art. Spring 92 is coupled with plunger 90 through 
a crank mechanism 94 and one end of the latter is secured to a rod 96 
mounting a stub shaft 98. Shaft 98 mounts an idler pulley 100 which is 
positioned to engage belt 102 of the power transmission 42 which drives 
gear 44 to rotate the tub sidewall. Shaft 98 is, in turn, carried by an 
arm 104 which is pivotally mounted to the machine frame. 
The arrangement just described is such that spring 92 exerts a biasing 
force tending to pull pulley 100 in a direction to loosen belt 102 to 
permit slippage in transmission 42 and thus diminish the power provided 
for rotating the tub sidewall. With the machine in normal operation, 
however, the speed of rotation of housing 84 derived from the power 
transmitted from the main power source is such that device 82 overcomes 
the bias of spring 92 and forces idler pulley 100 against belt 102 to 
tighten the belt and insure the transmission of driving force to rotate 
the tub sidewall. When the power consumed by the operation of apparatus 10 
is such, as when the comminution device becomes overloaded, to reduce the 
speed of rotation of the main drive, speed control apparatus 78 
automatically reduces the transmission of the motive force to the tub 
sidewall to slow the speed of the latter. This action temporarily 
diminishes the normal movement of material to the comminution device so 
that the latter is better able to handle the material already at the 
comminution station and prevents slugging or overloading of the machine. 
Once the comminution device has overcome the slug of material at the 
station, the speed of the main drive increases whereupon the speed 
governing device associated with the tub sidewall resumes its normal 
operating condition to permit the continued application of rotative force 
to the tub sidewall. 
An important feature of the present invention resides in the provision of 
novel chopping knives for the comminution device 32. As has been pointed 
out, the material frequently handled by apparatus 10 commonly involves 
straw, hay and similar materials having a high cellulose content and such 
materials have a tendency to wear the cutting edges of the chopping 
knives, increasing the horsepower requirements for the machine. This 
wearing action has a tendency to occur primarily at the outermost tips of 
the blades. Conventional sickle sections have heretofore been employed for 
cutting knives. Such sections typically present a pair of cutting edges 
and when the outer portions of these edges become worn, the sections are 
commonly removed and discarded. 
Referring now particularly to FIGS. 8, 9 and 10, a novel knife embodying 
the principles of this invention is broadly designated by the reference 
numeral 104. Knife 104 comprises a substantially flat, generally 
triangularly shaped body 106 having three elongated, sharpened cutting 
edges 108, 110 and 112, respectively, disposed peripherally around the 
body. As is apparent in FIG. 10 of the drawings each of the edges of the 
knife substantially defines one side of the body. An aperature 114 may be 
provided in the geometric center of the knife body and extends 
transversely therethrough to cooperate with a boss 116 integral with a 
holder 118 for mounting the knife in its proper cutting position as 
illustrated best in FIGS. 8 and 9. Holder 118 is provided with a pair of V 
shaped notches 120 and 122, each notch having a pair of inclined surfaces 
124 designed to complementally embrace the proximal flat surface of a 
corresponding knife 104 to hold the latter in the respective positions 
illustrated best in FIG. 8. Holder 118 is thus configured to mount four 
knives 104 in the upwardly projecting and outwardly diverging positions 
thereof shown in the drawings. A generally E shaped retainer 126 is 
configured to overlie holder 118 and has a pair of projecting legs 128 and 
130' projecting between each respective pair of knives 104. The side edges 
of the legs 128 are configured to complementally engage the proximal 
surfaces of the respective knives 104 to firmly clamp the latter in the 
positions illustrated. Retaining bolt 130 received through a retainer leg 
131 securedly clamps retainer 126 to holder 118 so that the knives may be 
removed from the position illustrated only upon the removal of bolt 130. 
Further, the inherent elasticity of the E shaped construction of retainer 
126 provides spring like clamping forces tending to accommodate for any 
lack of smoothness to the clamping surfaces and insures that the knives 
are held securely. 
Each holder 118 has an integral leg 134 adapted to be secured to wheel 34 
of the comminuting device 32 so that the knives 104 are mounted at 
regularly spaced intervals in radially projecting relationship on the 
wheel. Flange 136 integral with each leg 134 serves to reinforce the 
assembly. 
It will be readily understood by those skilled in the art that the novel 
knives 104 in the associated holding structure may be quickly and easily 
changed to present fresh and sharp cutting edges for the comminuting 
device. For example, if a knife 104 illustrated in FIG. 10 is mounted on 
the wheel so that its normal direction of rotation is to the right as 
viewed in that figure of the drawing, the leading uppermost end of edge 
108 will receive a major portion of the wear. When this portion of 108 
becomes sufficiently worn or dulled as to substantially increase the 
horsepower requirements for operating apparatus 10, the operator may 
loosen bolt 130 and rotate the position of knife 104 so that cutting edge 
112 is disposed in the position presently occupied by edge 108. When edge 
112 subsequently becomes worn in the manner heretofore described, knife 
104 may again be rotated to bring edge 110 into this cutting position. 
Once the knife has been used after it has been rotated to each of the 
three positions described above, the outermost projecting portion of each 
blade edge will have become dulled. The lowermost portion of the edges 
will not, to this time, have been substantially exposed to the dulling 
effects of the cutting operation. Thus, the operator may simply turn the 
knife over to reverse the positions of the flat sides, whereupon the 
heretofore substantially unworn portions of the sharpened blade edges will 
now be at the uppermost projecting ends of the knife. The operator may 
thereupon repeat the step of successive rotation of respective knife edges 
until each sharpened end of the edges has been rotated through the cutting 
position. 
It is now apparent that the novel cutting knife 104 presents to the 
operator the potential of six sharpened positions instead of the two 
sharpened positions heretofore available with conventional sickle 
sections. Although the construction of knife 104 has particular 
application for use in a tub chopper of the type described, it will be 
readily apparent that this construction may be advantageously utilized in 
a variety of other applications. For example, such blade construction may 
be used to advantage in any of a number of apparatus designed for cutting 
or chopping, such as in a conventional sickle bar mower, harvester or the 
like. 
It has been found that the proper comminution of material with machines 
such as apparatus 10 can be better assured by providing a grid in 
association with the comminution device. To this end, applicant has 
provided a grid 138 disposed interiorily in the chopping device housing 
140 and extending in radially outwardly spaced parallelism from the path 
of travel of knives 104 of the device. Grid 138 comprises a plurality of 
elongated spaced apart side by side longitudinal bars 142 interconnected 
by a plurality of spaced apart cross bars 144 to thereby define a mesh of 
a size deemed appropriate for the material involved. A plurality of teeth 
146 may be rigidly secured to bars 142 or bars 144 at inwardly projecting, 
spaced apart positions along the length of grid 138 as illustrated in the 
drawing. Teeth 146 are disposed at positions where they will not interfere 
with the path of travel of the respective knives 104 and will project 
generally between the projecting knives whereupon relatively long strands 
of material will have a tendency to be caught by teeth 146 to be severed 
by the rotating knives 104. All the material which has been severed to an 
extent that its size is sufficient to pass through the mesh of the grid 
goes through the latter to the material discharge 148. Any material which 
has not been comminuted to the required size is carried by the rotating 
knives 104 through device 32 for a subsequent trip along the grid until it 
is reduced to the appropriate size. Grid 138 is secured in inwardly spaced 
apart relationship from housing 140 by a plurality of bolts 150 and 
spacers 152. 
Another embodiment of chopping knives for comminution device 32 which 
embodiment is designed to further minimize the time and expense associated 
with knife wear is illustrated in FIGS. 14, 15 and 16 of the drawings. In 
this form of the invention, the knives 154 are disc shaped and have a 
single circular peripheral cutting edge 156. The discs may be either flat 
or dish shaped as shown in the drawings, depending upon what may be 
preferred for particular materials to be handled by the apparatus. In the 
embodiment illustrated, four discs 154 are mounted on a single shaft 156 
by a holder 158 and a retainer 160. A bearing 162 rotatably mounts shaft 
156 and the discs 154 are held in spaced apart relationship by spacers 
164. A grease fitting 166 is in communication with the bores 168 which 
threadably received retaining bolts 170. An opening 172 communicates with 
each of the bores 168 and is, in turn, communicated with an annular groove 
174 around bearing 162 by a duct 176. This construction permits 
lubrication material to be introduced through the fitting for maintaining 
lubrication to the bearing. 
It will be understood that each assembly mounting four knives 154 will be 
bolted to the rotatable cutter wheels 34 in substantially the manner 
described and illustrated in FIG. 7 referring to knives 104. Knives 154 
are thus disposed in projecting relationship around wheel 34 in position 
for cutting material encountered by the comminution device 32. The single 
peripherally extending cutting edge 156 of each knife engages the material 
and tends to be rotated thereby causing rotation of shaft 156 in its 
bearing. As a result of this action on each of the four knives mounted on 
a single shaft rotate together during the cutting operation. This rotation 
of the knives continually brings different portions of the sharpened 
cutting edges of the respective knives into the cutting position. Thus, 
the knives tend to wear uniformly throughout their entire perimeters so 
that it is unnecessary to change knives until the entire edges are dull to 
the point that the horsepower requirements for the operation of apparatus 
10 is increased substantially. Furthermore, the configuration of the discs 
may be such that the engagement of the material has a tendency to wear a 
disc edge in a "self sharpening" manner as is well known in art. 
It will be readily appreciated that the disc knives incorporated in the 
chopping device 32 in the manner heretofore set forth reduces the down 
time hertofore involved in operations utilizing knives of conventional 
construction. Accordingly, with the knives embodying the principles of 
this invention, a given set of knives may be used for long periods of time 
before it is necessary to halt the operation to change the knives. 
The operation of apparatus 10 is readily apparent from the foregoing 
description and reference to the disclosure contained in my co-pending 
application Ser. No. 229,347 filed Jan. 29, 1981, is incorporated herein 
by reference. Such machines have been found to be especially useful, not 
only for chopping feedstuffs for current animal consumption, but also for 
filling silos for feed storage for consumption at a later time. A farmer 
may bale his crop when it is ready and store it in baled form until he is 
ready to proceed with the silo filling operation. A variety of different 
crops may be harvested and stored in this manner. When the farmer is ready 
to put the feed into his silo, the bales are processed through the tub 
chopper where the proper particle sizes for the resultant ensilage is 
obtained. The bales of different crops may be appropriately selected 
during this processing to achieve the proper mix for the resultant 
ensilage. 
It has been found that apparatus constructed pursuant to the principles of 
this invention is beneficially adapted to permit the addition of water to 
the chopped feed at the time it is processed through the machine, and in 
amounts suitable for the production good ensilage in the silo. Water is 
simply introduced into the comminutor housing by suitable fittings (not 
shown) for this purpose when the material is processed by the machine. 
Corn and other grains may be admixed into the ration in a similar manner. 
Here again, such materials may be introduced through housing 140 by an 
auger or other suitable conveyor (not shown) communicating directly with 
the housing interior. 
Workmen assisting with the loading of material into the tub are exposed to 
possibility that they might inadvertently fall into the tub and thereby be 
injured by the rotating cutter knives. A guard 178 for safeguarding 
against this possibility is provided in the region where the tub loading 
takes place. Guard 178 includes an elongated, U shaped rail 180 having its 
ends secured to the machine frame, and a cross bar 182 secured to rail 
180. Guard 178 projects upwardly and inwardly from the lowermost lip of 
the tub sidewall in a position where it may be grasped by a workman to 
steady him against falling into the tub.