Note: Descriptions are shown in the official language in which they were submitted.
CA 02613956 2014-06-09
TITLE OF INVENTION
Hammermill Hammer
CROSS REFERENCE TO RELATED APPLICATIONS
This patent application is a continuation-in-part of US Patent 7,559,497
previously filed on
October 6, 2006 which was a continuation-in-part of US Patent 7,140,569.
Applicant herein
claims priority from the preceding referenced applications.
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BACKGROUND OF THE INVENTION
A number of different industries rely on impact grinders or hammermills to
reduce materials
to a smaller size. For example, hammermills are often used to process forestry
and
agricultural products as well as to process minerals, and for recycling
materials. Specific
examples of materials processed by hammermills include grains, animal food,
pet food, food
ingredients, mulch and even bark. This invention although not limited to
grains, has been
specifically developed for use in the grain industry. Whole grain corn
essentially must be
cracked before it can be processed further. Dependent upon the process, whole
corn may be
cracked after tempering yet before conditioning. A common way to carry out
particle size
reduction is to use a hammermill where successive rows of rotating hammer like
devices
spinning on a common rotor next to one another comminute the grain product.
For example,
methods for size reduction as applied to grain and animal products are
described in Watson,
S. A. & P. E. Ramstad, ed. (1987, Corn: Chemistry and Technology, Chapter 11,
American
Association of Cereal Chemist, Inc., St. Paul, Minn.). The application of the
invention as
disclosed and herein claimed, however, is not limited to grain products or
animal products.
Hammermills are generally constructed around a rotating shaft that has a
plurality of disks
provided thereon. A plurality of free-swinging hammers are typically attached
to the
periphery of each disk using hammer rods extending the length of the rotor.
With this
structure, a portion of the kinetic energy stored in the rotating disks is
transferred to the
product to be comminuted through the rotating hammers. The hammers strike the
product,
driving into a sized screen, in order to reduce the material. Once the
comminuted product is
reduced to the desired size, the material passes out of the housing of the
hammermill for
subsequent use and further processing. A hammer mill will break up grain,
pallets, paper
products, construction materials, and small tree branches. Because the
swinging hammers do
not use a sharp edge to cut the waste material, the hammer mill is more suited
for processing
products which may contain
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metal or stone contamination wherein the product the may be commonly referred
to as
"dirty". A hammer mill has the advantage that the rotatable hammers will
recoil
backwardly if the hammer cannot break the material on impact. One significant
problem with hammer mills is the wear of the hammers over a relatively short
period of
operation in reducing "dirty" products which include materials such as nails,
dirt, sand,
metal, and the like As found in the prior art, even though a hammermill is
designed to
better handle the entry of a "dirty" object, the possibility exists for
catastrophic failure
of a hammer causing severe damage to the hammermill and requiring immediate
maintenance and repairs.
Hamrnermills may also be generally referred to as crushers - which typically
include a
steel housing or chamber containing a plurality of hammers mounted on a rotor
and a
suitable drive train for rotating the rotor. As the rotor turns, the
correspondingly
rotating hammers come into engagement with the material to be comminuted or
reduced in size. Hammermills typically use screens formed into and
circumscribing a
portion of the interior surface of the housing. The size of the particulate
material is
controlled by the size of the screen apertures against which the rotating
hammers force
the material. Exemplary embodiments of hammermills are disclosed in U.S. Pat.
Nos.
5,904,306; 5,842,653; 5,377,919; and 3,627,212.
The four metrics of strength, capacity, run time and the amount of force
delivered are
typically considered by users of hammermill hammers to evaluate any hammer to
be
installed in a hammermill. A hammer to be installed is first evaluated on its
strength.
Typically, hammermill machines employing hammers of this type are operated
twenty-
four hours a day, seven days a week. This punishing environment requires
strong and
resilient material that will not prematurely or unexpectedly deteriorate.
Next, the
hammer is evaluated for capacity, or more specifically, how the weight of the
hammer
affects the capacity of the hammermill. The heavier the hammer, the fewer
hammers
that may be used in the hammermill by the available horsepower. A lighter
hammer
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then increases the number of hammers that may be mounted within the
hatnmermill for
the same available horsepower. The more force that can be delivered by the
hammer to
the material to be comminuted against the screen increases effective
comminution (i.e.
cracking or breaking down of the material) and thus the efficiency of the
entire
comminution process is increased. In the prior art, the amount of force
delivered is
evaluated with respect to the weight of the hammer.
Finally, the length of run time for the hammer is also considered. The longer
the
hammer lasts, the longer the machine run time, the larger profits presented by
continuous processing of the material in the harnmennill through reduced
maintenance
costs and lower necessary capital inputs. The four metrics are interrelated
and typically
tradeoffs are necessary to improve performance. For example, to increase the
amount of
force delivered, the weight of the hammer could be increased. However, because
the
weight of the hammer increased, the capacity of the unit typically will be
decreased
because of horsepower limitations. There is a need to improve upon the design
of
hammermill hammers available in the prior art for optimization of the four (4)
metrics
listed above.
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BRIEF SUMMARY OF THE INVENTION
The improvement disclosed and described herein centers on an improved hammer
to be used
in a hammermill. The improved metallic free swinging hammer is for use in
rotatable
hammer mill assemblies for comminution. The improved hammer is compromised of
a first
end for securement of the hammer within the hammer mill. The second end of the
hammer is
opposite the first end and is for contacting material for comminution. This
second end
typically requires treatment to improve the hardness of the hammer blade or
tip.
Treatment methods such as adding weld material to the end of the hammer blade
are well
known in the art to improve the comminution properties of the hammer. These
methods
typically infuse the hammer edge, through welding, with a metallic material
resistant to
abrasion or wear such as tungsten carbide. See for example U.S. Patent
#6,419,173,
describing methods of attaining hardened hammer tips or edges as are well
known in the prior
art by those practiced in the arts.
The methods and apparatus disclosed herein may be applied to a single hammer
or multiple
hammers to be installed in a hammermill. The hammer may be produced through
forging,
casting or rolling as found in the prior art. Applicant has previously taught
that forging the
hammer improves the characteristic of hardness for the hammer body. Applicant
has also
taught the thickness of the hammer edge, in relation to the hammer neck, may
also be
increased. Re-distributing material (and thus weight) from the hammer neck
back to the
hammer edge, to increase the moment produced by the hammer upon rotation while
allowing
the overall weight of the hammer to remain relatively constant. Applicant's
present design
may be combined with previous teachings related to the shape of the hammer and
the
methods of producing the hammer. Thus, the present design may enjoy an
increase in actual
hammer momentum available for comminution developed and delivered through
rotation of
the hammer than the hammers as found in the prior art. This increased momentum
reduces
recoil, as
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previously disclosed and claimed, thereby increasing operational efficiency.
However,
because the hammer design is still free swinging, the hammers can still
recoil, if
necessary, to protect the hammermill from destruction or degradation if a non-
destructible foreign object has entered the mill. Thus, effective horsepower
requirements are held constant, for similar production levels, while actual
strength,
force delivery and the area of the screen covered by the hammer face within
the
hammermill, per each revolution of the hammermill rotor, are improved. The
overall
capacity of a hammermill employing the various hammers embodied herein is
increased over existing hammers.
As taught, increasing the hammer strength and edge weld hardness creates
increases
stress on the body of the hammer and the hammer rod hole. In the prior art;
the
roundness of the rod hole deteriorates leading to elongation of the hammer rod
hole.
Elongation eventually translates into the entire hammer mill becoming out of
balance or
the individual hammer breaking at the weakened hammer rod hole area which can
cause a catastrophic failure or a loss of performance. When a catastrophic
failure occurs,
the hammer or rod breaking can result in metallic material entering the
committed
product requiring disposal. This result can be very expensive to large
processors of
metal sensitive products i.e. grain processors. Additionally, catastrophic
failure of the
hammer rod hole can cause the entire hammermill assembly to shift out of
balance
producing a failure of the main bearings and or severe damage to the
hammermill itself.
Either result can require the hammermill process equipment to be shutdown for
maintenance and repairs, thus reducing overall operational efficiency and
throughput.
During shutdown, the hammers typically must be replaced due to edge wear or
rod-
hole elongation.
Another embodiment of this invention illustrates an improved hammermill hammer
having an increased number of individual grinding surfaces or edges to improve
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comminution contact surface area The hammer design as shown has four (4)
individual edges that are offset in vertical height but are nearly equivalent
in radial
distance from the center point of the rod hole. During use, two (2) of the
four (4)
contacting edges are used. The hammer shown typically replaces a hammer having
only two (2) contacting edges of which only one (1) is used at a time. The
width of
each contacting edge as shown is equivalent to the width of the hammer. As
shown, the edges of the hammer have been welded to increase hardness. The
notched portions of the hammer end allow for pocketing and feed of the grain
to the
contacting edges. It is believed the hammer as shown will increase hammer
contact
efficiency and therefore overall hammermill efficiency. Although the present
art is
not so limited, when the present art is produced using forging techniques
versus
casting or rolling from bar stock the strength of the rod hole is improved and
there is
a noticeable decrease in the susceptibility of the rod hole to elongation.
Furthermore, this embodiment of the present art may be practiced with a hammer
body having of uniform shape.
In accordance with an aspect of the present invention, there is provided a
metallic
based hammer for use in a rotatable hammermill assembly comprising:
a. a first end for securement within said hammermill assembly;
b. a rod hole, said rod hole centered in said first end for engagement with
and attachment to said hammermill assembly;
c. a second end for contact and delivery of momentum to material to
be comminuted;
d. a neck connecting said first hammer end to said second hammer end;
and,
e. a shoulder, said shoulder surrounding at least a portion of said rod hole,
wherein a portion of said shoulder that surrounds at least a portion of
said rod hole adjacent said neck is reduced in the radial dimension.
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In accordance with another aspect of the present invention there is provided a
metallic based hammer for use in a rotatable hammermill assembly comprising:
a. a first end for securement within said hammermill assembly;
b. a rod hole, said rod hole centered in said first end for engagement with
and attachment to said hammermill assembly;
c. a second end for contact and delivery of momentum to material to
be comminuted;
d. a neck connecting said first hammer end to said second hammer end;
and,
e. a rod hole shoulder, said shoulder surrounding at least a portion of said
rod hole, wherein a portion of said rod hole shoulder that surrounds the
portion of said rod hole adjacent said neck is reduced in the radial
dimension,
f. and wherein said hammer is forged.
In accordance with another aspect of the present invention there is provided a
metallic based hammer for use in a rotatable hammermill assembly comprising:
a. a
first end for securement within said hammermill assembly; b. a rod hole, said
rod
hole centered in said first end for engagement with and attachment to said
hammermill assembly; c. a second end for contact and delivery of momentum to
material to be comminuted; d. a neck connecting said first hammer end to said
second hammer end; e. a first shoulder adjacent to and surrounding at least a
portion of said rod hole, wherein the thickness of said first shoulder is
greater than
the thickness of said neck, and wherein the thickness of said first shoulder
is greater
than the thickness of said first end; and f. a second shoulder adjacent to and
surrounding at least a portion of said rod hole and adjacent said neck,
wherein the
thickness of said second shoulder is greater than the thickness of said neck,
wherein
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the thickness of said second shoulder is greater than the thickness of said
first end,
wherein the distance around the periphery of said first shoulder is greater
than that
of said second shoulder so that said first shoulder and said second shoulder
are non-
symmetrical about the longitudinal axis of said rod hole.
In accordance with another aspect of the present invention, there is provided
a
metallic based hammer for use in a rotatable hammermill assembly comprising:
a.
a first end for securement within said hammermill assembly; b. a second end
for
contact and delivery of force to material to be comminuted; c. a neck
connecting
said first end to said second end; and d. a plurality of neck holes positioned
in said
neck, wherein said hammer is forged.
In accordance with another aspect of the present invention, there is provided
a
hammer for use in a rotatable hammermill assembly, said hammer comprising: a.
a connector end; b. a rod hole positioned in said connector end; c. a neck
having a
first and second end, said neck first end connected to said connector end; d.
a
contact end connected to said neck second end; e. a first shoulder adjacent to
and
surrounding a first portion of said rod hole; and f. a second shoulder
adjacent to
and surrounding a second portion of said rod hole, wherein said first shoulder
and
said second shoulder are non-symmetrical about the longitudinal axis of said
rod
hole.
In accordance with another aspect of the present invention, there is provided
a
hammer for use in a rotatable hammermill assembly, said hammer comprising: a.
a connector end; b. a rod hole positioned in said connector end; c. a first
shoulder
surrounding a first portion of said rod hole; d. a second shoulder surrounding
a
second portion of said rod hole wherein said first shoulder and said second
shoulder are non-symmetrical about the longitudinal axis of said rod hole; e.
a neck
having a first and second end, said neck first end connected to said connector
end;
and f. a contact end connected to said neck second end.
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In accordance with another aspect of the present invention, there is provided
a
hammer for use in a rotatable hammermill assembly, said hammer comprising: a.
a connector end; b. a rod hole positioned in said connector end; c. a first
shoulder
surrounding a first portion of said rod hole; d. a second shoulder surrounding
a
second portion of said rod hole, wherein a distance along the periphery of
said
second shoulder is less than a distance around the periphery of said first
shoulder;
e. a neck having a first and second end, said neck first end connected to said
connector end; and f. a contact end connected to said neck second end.
It is therefore an object of the present invention to disclose and claim a
hammer
design that is stronger and lighter because it of its thicker and wider
securement
end but lighter because of its thinner and narrower neck section.
It another object of the present art to improve the securement end of free
swinging
hammers for use in hammer mills while still using methods and apparatus found
in
the prior art for attachment within the hammermill assembly.
It is another object of the present invention to improve the operational
runtime of
hammermill hammers.
It is another object of the present invention to disclose hammers having
hardened
edges by such means as welding or heat treating.
It is another object of the present invention to disclose and claim a hammer
allowing
for improved projection of momentum to the hammer blade tip to thereby
increase
the delivery of force to comminution materials.
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It is another object of the present invention to disclose and claim a hammer
design that
is stronger and lighter because it is forged.
It is another object of the present invention to disclose and daim an
embodiment of the
present hammer design that weighs no more than three pounds.
It is another object of the present invention to disclose and claim a hammer
design that
allows for improved efficiency by increasing the number of hammer contact
edges.
It is another object of the present invention to disrlose and claim a hammer
design that
allows for improved efficiency by increasing the hammer contact surface area.
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BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention, reference is to be made
to the
accompanying drawings. It is to be understood that the present invention is
not limited
to the precise arrangement shown in the drawings.
FIG. 1 provides a perspective view of the internal configuration of a hammer
mill at rest
as commonly found in the prior art.
FIG. 2 provides a perspective view of the internal configuration of a
hanunerrnill during
operation as commonly found in the prior art.
FIG. 3 provides an exploded perspective view of a hammermill as found in the
prior art
as shown in Figure 1.
FIG. 4 provides an enlarged perspective view of the attachment methods and
apparatus
as found in the prior art and illustrated in Fig. 3.
FIG. 5 provides a perspective view of a first embodiment of the invention.
FIG. 6 provides an end view of the first embodiment of the invention.
FIG. 7 provides a side view of the first embodiment of the invention.
FIG. 8 provides a perspective of second embodiment of the invention.
FIG. 9 provides an end view of the second embodiment of the invention.
FIG. 10 provides a side view of the second embodiment of the invention.
FIG. 11 provides a perspective of third embodiment of the invention.
FIG. 12 provides a side view of the third embodiment of the invention.
FIG. 13 provides a top view of the third embodiment of the invention.
FIG. 14 provides a perspective of fourth embodiment of the invention.
FIG. 15 provides a side view of the fourth embodiment of the invention.
FIG. 16 provides a top view of the fourth embodiment of the invention.
FIG. 17 provides a perspective of fifth embodiment of the invention.
FIG. 18 provides a side view of the fifth embodiment of the invention.
FIG. 19 provides a top view of the fifth embodiment of the invention.
FIG. 20 provides a perspective of the sixth embodiment of the invention.
FIG. 21 provides an end view of the sixth embodiment of the invention.
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FIG. 22 provides side view of the sixth embodiment of the invention.
FIG. 23 provides a perspective of the seventh embodiment of the invention.
FIG. 24 provides an end view of the seventh embodiment of the invention.
FIG. 25 provides a side view of the seventh embodiment of the invention.
FIG. 26 provides a top view of the seventh embodiment of the invention.
FIG. 27 provides a perspective of the eight embodiment of the invention.
FIG. 28 provides an end view of the eight embodiment of the invention.
FIG. 29 provides a side view of the eight embodiment of the invention.
FIG. 30 provides a top view of the eight embodiment of the invention.
FIG. 31 provides a perspective view of the ninth embodiment of the invention.
FIG. 32 provides an end view of the ninth embodiment of the invention.
FIG. 33 provides a side view of the ninth embodiment of the invention.
FIG. 34 provides a top view of the ninth embodiment of the invention.
FIG. 35 provides a perspective view of the tenth embodiment of the invention.
FIG. 36 provides an end view of the tenth embodiment of the invention.
FIG. 37 provides a side view of the tenth embodiment of the invention.
FIG. 38 provides a top view of the tenth embodiment of the invention.
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DETAILED DESCRIPTION - LISTING OF ELEMENTS
Element Element #
= Hammermill
assembly 1
Hammermill drive shaft 2
End plate 3
= End plate drive
shaft hole 4
- End plate hammer rod hole 5
Center plate 6
Center plate drive shaft hole 7
Center plate hammer rod hole 8
Hammer rods 9
Spacer10
=
Hammer (swing or free-swinging) 11
Hammer body 12
Hammer tip 13
Hammer rod hole 14
Hammer center line 15
Center of rod hole 16
First end of hammer (securement end) 17
Thickness of first end of hammer 18
Radial distance to first and fourth contact points 19
Hammer neck 20
Radial distance to second and third contact points 21
Hammer neck hole 22
Second end of hammer (contact end) 23
Thickness of 2nd end of hammer 24
Hammer hardened contact edge 25
Linear distance from center line to first and fourth
contact points 26
Single stage hammer rod hole shoulder 27
Second stage hammer rod hole shoulder 28
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Hammer swing length (linear distance from center line
to second and third contact points) 29
Hammer Neck edges (hourglass) 30
Hammer Neck edges (parallel) 31
1st contact surface 32
2nd contact surface 33
3' contact surface 34
Secondary contact surface 35
1st contact point 36
2nd contact point 37
=
3rd contact point 38
4th contact point 39
Edge pocket 40
DETAILED DESCRIPTION
The present invention is more particularly described in the following
exemplary
embodiments that are intended as illustrative only since numerous
modifications and
variations therein will be apparent to those skilled in the art. As used
herein, "a," "an,"
or "the" can mean one or more, depending upon the context in which it is used.
The
preferred embodiments are now described with reference to the figures, in
which like
reference characters indicate like parts throughout the several views.
As shown in Figures 1-2, the harnmermills found in the prior art use what are
known as
free swinging hammers 11 or simply hammers 11, which are hammers 11 that are
pivotally mounted to the rotor assembly and are oriented outwardly from the
center of
the rotor assembly by centrifugal force. Figure 1 shows a hammermill assembly
as
found in the prior art at rest. The hammers 11 are attached to hammer rods 9
inserted
into and through center plates 6. Swing hammers 11 are often used instead of
rigidly
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connected hammers in case tramp metal, foreign objects, or other non-crushable
matter
enters the housing with the particulate material to be reduced, such as grain.
If rigidly attached hammers contact such a non-crushable foreign object within
the
hanunerrnill assembly housing, the consequences of the resulting contact can
be severe.
By comparison, swing hammers 11 provide a "forgiveness" factor because they
will "lie
back" or recoil when striking non-crushable foreign objects.
Figure 2 shows the haznmennill assembly 1 as in operation. For effective
reduction in
hammermills using swing hammers 11, the rotor speed must produce sufficient
centrifugal force to hold the hammers in the fully extended position while
also having
sufficient hold out force to effectively reduce the material being processed.
Depending
on the type of material being processed, the minimum hammer tips speeds of the
hammers are usually 5,000 to 11,000 feet per minute ("FPM"). In comparison,
the
maximum speeds depend on shaft and bearing design, but usually do not exceed
30,000
FPM. In special high-speed applications, the hammermills can be designed to
operate
up to 60,000 FPM.
Figure 3 illustrates the parts necessary for attachment and securement within
the
hammennill hammer assembly 1 as shown. Attachment of a plurality of hammers 11
secured in rows substantially parallel to the harnmermill drive shaft 2 is
illustrated in
Figure 3 and 4. The hammers 11 secure to hammer rods 9 inserted through a
plurality of
center plates 6 and end plates 3 wherein the plates (3,6) orient about the
hanunermill
drive shaft 2. The center plates 6 also contain a number of distally located
center plate
hammer rod holes 8. Hammer pins, or rods 9, align through the holes 3,6 in the
end
and center plates 3,6 and in the hammers 11. Additionally, spacers 10 align
between the
plates. As is well known to those of skill in the arts, a lock collar (not
shown) would be
placed on the end of the hammer rod 9 to compress and hold the spacers 10 and
the
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hammers 11 in alignment. All these parts require careful and precise alignment
relative
to each other.
In the case of disassembly for the purposes of repair and replacement of worn
or
damaged parts, the wear and tear causes considerable difficulty in realigning
and
reassembling of the rotor parts. Moreover, the parts of the hanunermill hammer
assembly 1 are usually keyed to each other, or at least to the drive shaft 2,
this further
complicates the assembly and disassembly process. For example, the replacement
of a
single hammer 11 can require disassembly of the entire hammer assembly 1.
Given the
frequency at which wear parts require replacement, replacement and repairs
constitute
an extremely difficult and time consuming task that considerably reduces the
operating
time of the size reducing machine. As shown in Figures 3 and 4 for the prior
art,
removing a single damaged hammer 11 may take in excess of five (5) hours, due
to both
the rotor design and to the realignment difficulties related to the problems
caused by
impact of debris with the non-impact surfaces of the rotor assembly.
Another problem found in the prior art rotor assemblies shown in Figures 1-4
is
exposure of a great deal of the surface area of the rotor parts to debris. The
plates 3 and
6, the spacers 10, and hammers 11 all receive considerable contact with the
debris. This
not only creates excessive wear, but contributes to realignment difficulties
by bending
and damaging the various parts caused by residual impact. Thus, after a period
of
operation, prior art hammermill hammer assemblies become even more difficult
to
disassemble and reassemble. The problems related to comminution service and
maintenance of hamrnermills provides abundant incentive for improvement of
hanunermill hammers to lengthen operational run times.
The hammer 11 embodiments shown in Figures 5-22 are mounted upon the
hammermill rotating shaft at the hammer rod hole 14. As shown, the effective
width of
hammer rod hole 14 for mounting of the hammer 11 has been increased in
comparison
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to the hammer neck 20 in Figures 5-22. The hammer neck 20 may be reduced in
size
because forging the steel used to produce the hammer results in a finer grain
structure
that is much stronger than casting the hammer from steel or rolling it from
bar stock as
found in the prior art. As disclosed in the prior art a loci collar (not
shown) secures the
hammer rod 9 in place. Another benefit of the present art is that the amount
of material
surface supporting attachment of the hammer 11 to the rod 9 is dramatically
increased.
This has the added benefit of eliminating or reducing the wear or grooving of
the
hammer rod 9. The design shown in the present art at figures 5-22 increases
the surface
area available to support the hammer 11 relative to the thickness of the
hammer 11.
Increasing the surface area available to support the hammer body 11 while
improving
securement also increases the amount of material available to absorb or
distribute
operational stresses while still allowing the benefits of the free swinging
hammer
design i.e. recoil to non-destructible foreign objects.
Figures 5-7 show a first embodiment of the present invention, particularly
hammers to
be installed in the hammermill assembly. Figure 5 presents a perspective view
of this
embodiment of the improved hammer 11. As shown, the first end of the hammer 17
is
for securement of the invention within the hammermill assembly 1 (not shown)
by
insertion of the hammer rod 9 through hammer rod hole 14 of the hammer 11. In
figure
the center of the rod hole 16 is highlighted. The distance from the center of
rod hole 16
to the contact or second end of the hammer 23 is defined as the hammer swing
length
29. Typically, the hammer swing length 29 of the present embodiment is in the
range of
eight (8) to ten (10) inches with most applications measuring eight and five
thirty
seconds inches (85/32")' to nine and five thirty seconds (9 5/32") .
In the embodiment of the hammer 11 shown in Figures 5-7, the hammer rod hole
14 is
surrounded by a single stage hammer rod hole shoulder 27. In this embodiment,
the
hammer shoulder 27 is composed of a raised single uniform ring surrounding rod
hole
14 which thereby increases the metal thickness around the rod hole 14 as
compared to
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the thickness of the first end of the hammer 18. The placement of .a single
stage hammer
shoulder 27 around the hammer rod hole 14 of the present art hammer increases
the
surface area available for distribution of the opposing forces placed on the
hammer rod
hole 14 in proportion to the width of the hammer thereby decreasing effects
leading to
rod hole 14 elongation while the hammer 11 is still allowed to swing freely on
the
hammer rod 9.
In this embodiment, the edges of the hammer neck 20 connecting the first end
of the
hammer 17 to the second end of the hammer 23 are parallel or straight.
Furthermore,
the thickness of the second end of the hammer 24 and the thickness of the
first end of
the hammer 18 are substantially equivalent. Because the second end of the
hammer 23 is
in contact with materials to be comminutated, a hardened contact edge 25 is
welded on
the periphery of the second end of the hammer 23.
Figure 6 provides an end view of the first embodiment of the invention and
further
illustrates the thickness of the hammer shoulder 27 in relation the hammer 11
as well as
the symmetry of the hammer shoulder 27 in relationship to the thickness of
both the
first hammer end 17 and second hammer end 23 as shown by hardened welded edge
=
25. Figure 7 illustrates the flat, straight forged plate nature of the
invention, as shown by
the parallel edges of the hammer neck 31 from below the hammer shoulder 27
through
the hammer neck 20 to second end 23 which provides an improved design through
overall hammer weight reduction as compared to the prior art wherein the
hammer
neck 20 thickness is equal to the hammer rod hole thickness 14.In the present
art, the
total thickness of the rod hole 14, including the hammer shoulder 27, may be
one and
half to two and half times greater than the thickness of the hammer neck 20.
In typical
applications, the swing length of the present art is in the range of four (4)
to eight (8)
inches. For example, the forged steel hammer 11 of the first embodiment having
a
swing length of six (6) inches has a maximum average weight of three (3)
pounds. A
forged hammer of the prior art with an equivalent swing length having a
uniform
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CA 02613956 2007-12-10
thickness equal to the thickness of the hammer shoulder 27 would weigh up to
four (4)
pounds. The present invention therefore improves overall hammermill
performance by
thirty-three (33%) percent over the prior art through weight reduction without
an
accompanying reduction in strength. As shown, the hammer requires no new
installation procedures or equipment.
The next embodiment of hammer 11 is shown in Figures 8-10. As shown, the
hammer
rod hole 14 is again reinforced and strengthened over the prior art. In this
embodiment,
the rod hole 14 has been strengthened by increasing the thickness of the
entire first end
of the hammer 18. By comparison, the thickness of hammer neck 20 in this
embodiment
has been reduced, again effectively reducing the weight of the hammer in
comparison
to the increased metal thickness around the rod hole 14. This embodiment of
the present
art hammer also increases the surface area available for distribution of the
opposing
forces placed on the hammer rod hole 14 in proportion to the thickness of the
hammer
thereby again decreasing effects leading to rod hole 14 elongation while the
hammer 11
is still allowed to swing freely on the hammer rod 9. The thickness of the
second end of
the hammer 24 and the thickness of the first end of the hammer 18 are
substantially
equivalent. Because the second end of the hammer 23 is in contact with
materials to be
cornminutated, a hardened contact edge 25 is welded on the periphery of the
second
end of the hammer 23.
Figure 8 best illustrates the curved, rounded nature of the second embodiment
of the
present invention, as shown by the arcuate edges from the first end of the
hammer 17
and continuing through hammer neck 20 to the second hammer end 23. To further
reduce hammer weight, hammer neck holes 22 have been placed in the hammer neck
20. The hammer neck holes 22 may be asymmetrical as shown or symmetrical to
balance
the hammer 11. The arcuate, circular or bowed nature of the hammer neck holes
22 as
shown allows transmission and dissipation of the stresses produced at the
first end of
the hammer 17 through and along the neck of the hammer 20.
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As emphasized and illustrated by figures 8 and 10, the reduction in hammer
neck
thickness and weight allowed through both the combination of the hammer neck
shape
and hammer neck holes 22 provide improved hammer neck strength at reduced
weight
therein allowing increased thickness at the first and second ends of the
hammer, 17 and
23, respectively, to improve both the securement of said hammer 11 and also
delivered
force at the comminution end of the hammer 23.
The next embodiment of hammer 11 is shown in Figures 11-13. The perspective
view
found at figure 11 provides another embodiment of the present forged hammer
which
accomplishes the twin objectives of reduced weight and decreased hammer rod
hole
elongation. The hammer rod hole 14 is again reinforced and strengthened over
the prior
art in this embodiment which incorporates hammer rod hole reinforcement via
two
stages labeled 27 and 28. This design provides increased reinforcement of the
hammer
rod hole 14 while allowing weight reduction because the rest of the first end
of the
hammer 18 may be the same thickness as hammer neck 20. This embodiment of the
present art hammer also increases the surface area available for distribution
of the
opposing forces placed on the hammer rod hole 14 in proportion to the width of
the
hammer thereby again decreasing effects leading to rod hole 14 elongation
while the
hammer 11 is still allowed to swing freely on the hammer rod 9. As shown by
figure 13,
the thickness of the second end of the hammer 24 and the thickness of the
first end of
the hammer 17 are substantially equivalent. Because the second end of the
hammer 23 is
in contact with materials to be cornminutated, a hardened contact edge 25 is
welded on
the periphery of the second end of the hammer 23.
Figure 11 illustrates the curved hammer neck edges 30 which give the hammer 11
an
hourglass shape starting below the hammer rod hole 14 and at the first end of
the
hammer 17 and continuing through the hammer neck 20 to the second end of the
hammer 23. Incorporation of this shape into the third embodiment of the
present
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CA 02613956 2007-12-10
invention assists with hammer weight reduction while also reducing the
vibration of
the hammer 11 as it rotates in the hammer mill and absorbs the shock of
contact with
comminution materials.
As shown and illustrated by Figure 13 which provides a side view of the
present
embodiment, the first end of the hammer 17, the neck 20 and the second end of
the
hammer 23 are of a substantially similar thickness with the exception of the
stage 1 and
2 hammer rod hole reinforcement shoulders, 27 and 28, to maintain the hammer's
reduced weight over the present art. As emphasized and further illustrated by
figures
11-13, the reduction in the hammer profile and weight allowed through both the
combination of the hammer neck shape 30 and thicknesS provide improved hammer
neck strength at reduced weight therein allowing placement of the stage 1 and
2
hammer rod hole reinforcement shoulders, 27 and 28, respectively, around the
hammer
rod hole 14 to improve both the securement of said hammer 11 and performance
of the
hammermill.
Figures 1446 illustrate a modification of the present invention as shown in
previous
figures 8-10. In this embodiment the hammer 11 is shown without the hammer
neck
holes 22 shown in figures 8-10. This embodiment of the present invention,
without
hammer neck holes 22, provides an improvement over the present art by
combining a
thickened or thicker hammer rod hole 14 by increasing the thickness of the
first or
securement end of the hammer 17 in relation to the hammer neck 20 and second
end of
the hammer 23. This modification of the embodiment is lighter and stronger
than the
prior art hammers.
Figures 17-19 present another embodiment of the present art wherein the first
end of the
hammer 17, the hammer neck 20 and the second end of the hammer 23 are
substantially
of similar thickness i.e. the dimensions represented by 18 and 24 are
substantially
equivalent. In this embodiment, the hammer rod hole 14 has been strengthened
through
placement of a single reinforcing hammer shoulder 27 around the perimeter of
the
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hammer rod hole 14, on both sides or faces of the hammer 11. The rounded shape
of the
first end of the hammer 17 strengthens the first end of the hammer 17 by
improving the
transmission of any hammer rod 9 vibration away from the securement end of the
hammer 17 through the hammer neck 20 to the second end of the hammer 23. The
round shape also allows further weight reduction. In this embodiment, the
hammer
neck edges 31 are parallel as are the hammer neck edges in Figures 5-7. A
hardened
contact edge 25 is shown welded on the periphery of the second end of the
hammer 23.
Figures 20-22 present another embodiment of the present art wherein the first
end of the
hammer 17, the hammer neck 20 and the second end of the hammer 23 are
substantially
of similar thickness i.e. the dimensions represented by 18 and 24 are
substantially
equivalent. In this embodiment, the hammer rod hole 14 has been strengthened
through
placement of a single reinforcing stage 27 around the perimeter of the hammer
rod hole
14, on both side or faces of the hammer 11. A hardened contact edge 25 is
shown
welded on the periphery of the second end of the hammer 23. In this particular
embodiment, the hammer neck edges 30 have been rounded to further improve
vibration energy transfer to the second end of the hammer. 23 and away from
the
securement end of the hammer 17.
Figures 23-30 illustrate two additional embodiments of the present art. As
shown, the
hammers 11 illustrated in Figures 23-30 present an increased number of
individual
contact surfaces to improve available comminution contact surface area. This
improvement may be embodied in hammers 11 produced using either casting or
forging techniques. Additionally, the body of the hammer 12 may be improved by
heat
treatment methods known to those practiced in the arts for improved wear
characteristics.
Typically, the hammer 11 embodiments shown in Figures 23-26 are mounted upon
the
hammermill rotating shaft at the hammer rod hole 14. As disclosed in the prior
art a
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lock collar (not shown) secures the hammer rod 9 in place. As shown in Figures
23-26,
the thickness cif the neck connecting said the first hammer end to the second
hammer
end has not been reduced in relation to first and second hammer ends. During
typical
use of the present embodiment, two of the three contacting surfaces edges are
used. As
those practiced in the arts will understand, the metallic based hammer as
disclosed may
be used bi-directionally by either reversing the direction of rotation of the
harnmermill
assembly or in a fixed direction of rotation hammermill assembly, the hammer
may be
re-installed in the hamrnermill assembly in a reverse orientation to allow a
reversal of
the contact surfaces as described further herein.
The second end of the hammer 23 has three distinct contact surfaces (32, 33,
34)
respectively. The hammer 11 as shown is symmetrical along the length of the
hammer
neck 20 so that during normal operation in a first direction of rotation, the
edges of the
first and second contact surfaces, 32 and 33, respectively, will be the
leading surfaces.
The third contact surface will be a trailing edge and will wear very little.
The first
contact point 36 and the second contact point 37 will be the leading contact
points. The
third contact point 38 and the fourth contact points 39 will be the trailing
contact points
and will wear very little.
If the direction of rotation of the hammer 11 is reversed, either by reversing
the
direction of rotation of the hammermill assembly 1 or re-installing the hammer
11 in the
opposite orientation, the third contact surface 34 and the second contact
surface 33 will
be the leading surfaces. The third contact point 38 and the fourth contact
point 39 will
be the leading contact points. The first contact point 36 and the second
contact point 37
will then be in the trailing position.
As shown, the combined width of the contacting surfaces (32,33 and 34) is
substantially
equivalent to the width of the second end of the hammer 11. In the embodiments
shown, the edges of the hammer 11 have been welded to increase hardness.
Tungsten
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carbide has been applied by welding to the periphery of the second end for
increased
hardness. Other types of welds as well known to those practiced in the arts
may also be
applied.
As best shown in Figure 26, the distance to the second contact surface 33 from
the rod
hole centerline 15 is not equal to the distance from rod hole centerline 15 to
the first and
third contact surfaces, 32 and 34, respectively. The three contact surfaces
(32,33 and 34)
have first 36, second 37, third contact 38 and fourth contact 39 points for
contact and
delivery of momentum to the material to be comminuted. The radial distance
from the
center of the rod hole 16 to the first 36, second 37, third 38 and fourth 39
contact points
are equal. This spatial relationship is best illustrated in Figures 26 and
Figures 30. The
radial distance from the center of the rod hole 16 to the first and fourth
contact points,
36 and 39, respectively, is labeled 19. The radial distance from the center of
the rod hole
16 to the second and third contact points, 37 and 38, respectively, are
labeled 21.
Figures 27-30 illustrate another version of the present art wherein an edge
pocket 40 has
been placed at the second end of the hammer 23. The edge pocket(s) 40 are
notched
portion(s) placed fore and aft of the second contact surface 33 to allow
temporary
insertion or "pocketing" of the comminution materials during rotation of the
hanunermill assembly 1 to increase loading upon the contacting surfaces and
thereby
increase hammer contact efficiency and overall hammermill efficiency. The
depth of the
hammer edge pocket is proportional to the difference between the hammer swing
length 29 and the distance from the rod hole center line 15 to the first or
third contact
surfaces, 32 and 34, respectively. The depth of the hammer edge pocket is in
the range
of 0.25 to 2 times the thickness of the hammer. The geometry of the edge
pocket 39 may
be rounded or sloped (not shown).
In the embodiment shown in figures 27-30 the effective width of hammer rod
hole 14
for mounting of the hammer 11 has been increased in comparison to the hammer
neck
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20 in Figures 1-4. The hammer neck 20 may be reduced in size because forging
the steel
used to produce the hammer results in a finer grain structure that is much
stronger than
casting the hammer from steel or rolling it from bar stock as found in the
prior art. As
disclosed in the prior art a lock collar (not shown) secures the hammer rod 9
in place.
Another benefit of the present art is the amount of material surface
supporting
attachment of the hammer 11 to the rod 9 is dramatically increased. This has
the added
benefit of eliminating or reducing the wear or grooving of the hammer rod 9.
The
design shown in the present art at figures 27-30 increases the surface area
available to
support the hammer 11 relative to the thickness of the hammer 11. Increasing
the
surface area available to support the hammer body 11 while improving
securement also
increases the amount of material available to absorb or distribute operational
stresses
while still allowing the benefits of the free swinging hammer design i.e.
recoil to non-
destructible foreign objects.
Figures 31-34 present another embodiment of the present art wherein the first
end of the
hammer 17, the hammer neck 20, and the second end of the hammer 23 are.
substantially of similar thickness. That is, as shown in FIG. 33 the thickness
of first end
of hammer 18, the thickness of the hammer neck 20, and the thickness of second
end of
hammer 24 are substantially equivalent. In this embodiment, the hammer rod
hole 14
has been strengthened through placement of a single stage hammer rod hole
shoulder
27 around a portion of the perimeter of the hammer rod hole 14 on both sides
or faces of
the hammer 11, as shown in FIG. 32. As shown, the shoulder 27 surrounding a
portion
of the hammer rod hole 14 adjacent the hammer neck 20 is reduced in the radial
dimension. The rounded shape of the first end of the hanuner 17 strengthens
the first
end of the hammer 17 by improving the transmission of any hammer rod 9
vibration
away from the first end of the hammer 17 (i.e., the end of the hammer 11 that
is engaged
with the hammer rod 9) through the hammer neck 20 to the second end of the
hammer
23. The round shape also allows further weight reduction. In this embodiment,
the
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hammer neck edges 30 are rounded. A hammer hardened contact edge 25 is shown
welded on the periphery of the second end of the hammer 23.
Figures 35-38 present another embodiment of the present art wherein the first
end of the
hammer 17 and the hammer neck 20 are substantially of similar thickness. That
is, as
shown in FIG. 37, the thickness of the first end of hammer 18 and the
thickness of the
hammer neck 20 are substantially equivalent. However, the thickness of the
second end
of hammer 24 is greater than either the thickness of the hammer neck 20 or the
thickness
of the first end of hammer 18. In this embodiment, the hammer rod hole 14 has
been
strengthened through placement of a single stage hammer rod hole shoulder 27
around
a portion of the perimeter of the hammer rod hole 14 on both sides or faces of
the
hammer 11, as shown in FIG. 36. A hardened contact edge 25 is shown welded on
the
periphery of the second end of the hammer 23. In this particular embodiment,
the
hammer neck edges 30 have been rounded to further improve vibration energy
transfer
to the second end of the hammer 23 and away from the first end of the hammer
17 (i.e.,
the end of the hammer 11 that is engaged with the hammer rod 9). As shown, the
shoulder 27 surrounding a portion of the hammer rod hole 14 adjacent the
hammer
neck 20 is reduced in the radial dimension.
Those practiced in the arts will understand that the advantages provided by
the
hammer design disclosed may be produced by other means not disclosed herein
but=
still falling within the present art taught by applicant.
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