Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
I
~CKGROUND OF THE INVENTION
This invention relates to a cap for fitting on a disc of
a hammer mill disc rotor to a rotor fitted with a plurality
of caps, to apparatus for shredding materials using such
rotor, and to a method of retrofitting hammer mill rotors with
capped discs. The hammers rotate on pins extending between
the discs. This patent application is an improvement over
U.S. Patent Nos. 3,482,789 and 3,~82,787.
DESCRIPTION OF THE PRIOR ART
Many different types of products have been designed in the
past for shredding scrap metal One of the largest sources of
scrap metal is old automobile bodies. To get the metal into
scrap form for reuse, it becomes necessary to pulverize, shred
or otherwise break the metal into small pieces. In the past,
this has been accomplished a number of ways with U.S. Patent
No. 3,~82,788 being a typical example. A rotor is located
inside ox a hammer mill, which rotor is turned by a large
motor at a high rate of speed. The rotor consists of a shaft
with a plurality of discs being spaced along the shaft. Pins
extend through the discs near the outer periphery thereof and
have spacers separating each of the individual discs. Hammers
are spaced along the pins at locations not occupied by spacers
and are free to rotate thereabout. As the rotor rotates at a
high rate of speed, the hammers strike the metal being
pulverized or shredded. If the hammers strive too hard on an
object that is not pulverized or broken in one blow, the
hammers are free to rotate about the pin to allow the rotor
to continue to rotate however, this system has problems of
excessive wear of the discs.
In an effort to overcome the wear of the discs foaled on
the rotor, protective caps were designed and provided as
1 I shown in U.S. Patent No. 4l056,232. However, these caps have
2 1 inherent problems that occur during use. Further, the
3 I caps were large and bulky and difficult to install. Installation
4 ! of the caps requires that the pins be removed, the caps
5 it inserted in place of the spacers along the pins, and the
6 I caps secured in place This creates excessive weight in the
7 Al rotor and requires considerably more material and power.
8 I In use, it has been found that the leading edge of the caps
9 lo would tend to rise up. After the leading edge begins to
rise, the caps can rip off causing damage to the pins,
11 1 discs or rotor. Whenever the caps need to be replaced, it
12 it involves a major overhaul job whereby each of the pins have
13 to be removed (many times requiting special pin pullers),
14 ¦ the cups cut away from the discs if they are branded into
15 if place, and replaced with new caps. This is a very time
16 I consuming job with the caps themselves being quite expensive.
17 Another type of hammer mill having a rotor assembly
I 1 utilizes what is commonly called a "spider" rotor. Because
19 the arms of the spider had the same problems with wear as
the discs would have in a "disc-type" rotor, the spiders
21 , needed some type of protective cap or tip. A typical such
22 I spider rotor having a protective cap or tip is shown in
23 U.S. Patent No. 3,727,848. Again, the hammers freely swing
24 on pins extending through the spider arms, but the spider
25 lo arms are protected by replaceable caps or tips located on
26 Al the leading edge of -the spider arms. However, the spider-type
27 if rotor is less desirable than the disk-type rotor because it
I l' normally does not have as many hammers and metal can become
29 lodged between the various spider arms. Spider type rotors
are more subject to direct hits than disc-type rotors, which
31 Al direct hits increase vibrations, shocks and incidents of
32 l damage. For example, the spider arm can break way from the
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I
1 it shaft. These problems are lessened with the disc-type rotor.
2 if Another typical example of a spider-type rotor having a
3 ', replaceable cap attached to the pins extending there through
4 I is shown in U.S. Patent No. 3,844,494~ However, this has
5 if the inherent problems that all spider-type rotors have of
6 I- less capacity and vibration or shock problems.
7 lo The prior art for related crusher devices is very old
8 lo having originally been developed in connection with the
9 lo crushing of grain products, such as corn. A typical
10 if turn-of-the-century type of crusher or pulverizer is shown
11 'I in U.S. Reissue Patent No. 12,659 issued in 1907. large
12 I rotor is used with discs or plates connected thereto and
13 lo hammers being swung on pins extending through the discs.
14 Jo However, when the type of crusher or pulverizer as shown in
the aforementioned Reissue Patent No. 12,659 is modified
16 1 for shredding metal products, many problems that had not
17 Al occurred before begin to occur, such as problems of excessive
18 I wear not only on the hammers and on the grinding or crushing
1g Jo surface, but also on the supporting discs themselves.
20 1 Another typical early patent is shown in U.S. Patent
21 if No. 589,236 issued in 1897, which shows a spider-type crusher
22 lo or pulverizer. A whole series of these patents around the
23 I turn of the century are either invented by Milton F. Williams
24 1 of St. Louis, Missouri, or assigned to the Williams Patent
I Crusher and Pulverizer Company of St. Louis, Missouri.
26 A patent that pictorially shows a shredder-type hammer
27 mill used for shredding car bodies is U.S. Patent No.
28 1 3,545,690, which hammer mill utilizes a spider-type rotor.
29 ; In recent years, there have been further improvements in the
hammers with the use of manganese, which has a tendency -to
31 work harden to prevent wear. However, such material has a
32 tendency to be ductile during the period of time that it is
SUE
work hardening. A patent addressing this particular
problem it U.S. Patent No. 3,738,586.
U.S. Patent No, 2,781,176 issued to Clark discloses
a rotor rim having tangential flats upon which blades are
retained by blade retaining bars having angled edges. U.S.
Patent No. 4,146,184 issued to Whitney discloses a shredder
having a door which contains a discharge grate and which
can be opened to permit unshreddables to be removed. U.S.
Patent No. 4,214,616 issued to Brazen discloses a tree
delimbing device having a roller outside the housing and a
roller inside the housing. U.S. Patent No. 4,313,575
issued to Stepanek discloses crossed disposed rotor plates
which leave spaces between the projecting end portions of
the rotor plates.
In the past, a special heat treating or hard surface
welding process has been used to coat the outer surface of
the discs r which process is very time consuming and
expensive
In the present application, a very simple type of cap
that is attached to the disc is provided, which cap can be
easily removed and replaced without the necessity of having
to pull the pins in the rotor. The pulling of the pins in
the rotor is a major job and requires considerable labor
and equipment. All of these problems have been overcome
with the present invention.
SUMMARY OF THE INVENTION
The present invention consists of a cap for fitting on
a disc of a hammer mill disc rotor used for shredding
material, said cap comprising: an arcuate outer surface, a
leading edge at an obtuse angle relative to said outer
surface, and a trailing edge at an acute angle relative to
said outer surface; and an inner surface having at least
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one undercut therein adapted to receive an outward
protrusion of said disc.
The invention also consists of a cap for fitting on a
disc of a hammer mill disc rotor used for shredding
material, said cap comprising: an arcuate outer surface, a
leading edge at an obtuse angle relative to said outer
surface, and a trailing edge at an acute angle relative to
said outer surface; and an inward protrusion defining a
first undercut on a leading end of said cap and a second
undercut on a trailing end of said cap.
The invention also provides a rotor for use in a hammer
mill for shredding material, comprising: a shaft; a pour-
amity of generally circular discs located on said shaft
means for preventing rotation of said discs with respect
to said shaft; pins extending through holes in said discs
near an outer periphery thereof; hammers pivotal mounted
on said pins at predetermined locations for impacting
materials to be shredded; and a plurality of caps removably
attached to said outer periphery of said discs, each of
said caps comprising an arcuate outer surface, a leading
edge at an obtuse angle relative to said outer surface,
and a trailing edge at an acute angle relative to said
outer surface; and an inward protrusion defining a first
undercut on a leading end of said cap and a second
undercut on a trailing end of said cap.
In addition the invention provides apparatus for
shredding materials, comprising a housing; rotor means
located in said housing, said rotor means including a
plurality of generally circular discs located on a shaft;
a plurality of pins extending through said discs near an
outer periphery thereof, a plurality of caps removably
I- attached to said outer periphery of said discs, each of
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said caps comprising: an arcuate outer surface, a leading
edge at an obtuse angle relative to said outer surface, and
a trailing edge at an acute angle relative to said outer
surface; and an inward protrusion defining a first undercut
on a leading end of said cap and a second undercut on a
trailing end of said cap; means for feeding materials to be
shredded into said housing through an inlet opening; hammers
on said pins for shredding materials passing through said
inlet opening; and means for -turning said rotor.
In its method aspect, the invention consists of a method
of retrofitting hammer mill rotors with capped discs
comprising the steps of: first removing said rotor from a
hammer mill; second removing of discs from a shaft of said
rotor; alternatively either: (1) replacing said discs, or
(2) reshaping said discs to discs that are generally
circular but with outward protrusions thereon; forming in
said discs a means for attaching work hardening caps thereto,
attaching said caps to said discs via said attaching means,
said caps overlapping said protrusions of said replaced/
reshaped discs to form a circular cap and disc of a diameter
generally the same as before said first or second removing;
first reinstalling of said discs on said shaft; and second
reinstalling of said rotor in said hammer mill, wherein said
attaching step comprises further ship lapping of said caps
end to-end to have an obtuse leading outer edge and an acute
trailing outer edge.
The invention may be used with a shredder of metal
products, with typical products being used appliances or
automobile bodies. For increased capacity and energy
efficiency, the shredder has both a top and bottom discharge
for discharging the metals after shredding The shredder
uses a disc-type rotor having discs that are spaced apart by
spacing rings
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I Around the outer periphery of the rotor are located pins
I, extendincJ through discs on which spacing rings are provided.
Al Hammers are suspended on the pins at dispersed locations where
I spacing rings are not located. The hammers are free to rotate
Lowe around the pins and between contiguous discs. As the rotor
Al, turns at a high rate o-f speed, the centrifugal force extends
7 , the hammers outward, which hammers impact on scrap metal being
Al fed into the shredder. The impacting hammers either shred or
9 I pulverize the material being fed into the shredder. As the
10l~ scrap material is being fed into the shredder and broken into
pieces by the hammers, the scrap material impacts against the .
12i, discs holding the pins on which the hammers are suspended.
13 if The impacting of the metal against the discs tends to wear
the outer surface of the discs.
15 ill To prevent wear to the outer surface of the discs, a cap
16 if made from manganese or a manganese steel alloy or similar
17~l characteristic alloy steel) is bolted onto the outer surface
18 11 owe the discs. The discs, which are generally circumferential
19 1 in nature, have raised portions centered in the middle owe each
20 ill cap or grooves for receiving a cap protrusion centered in the
21 I middle of each cap. Each end of the caps are overlapping in a
22l ship lap manner with the adjacent cap. Bolts through the caps
23 1 into the discs physically anchor the caps in position. After
24~l running the hammer mill with the capped discs a short period
25 Al of time, the manganese or austenitic manganese steel is work
26 hardened into position on the discs. Due to the work hardening
27 and the setting of the caps on the discs, normally it is
28 , necessary to tighten the bolts a couple of times during the
29 early running of the hammer mill.
The ship lapping of each end of the caps are arranged in
31 Jo such a manner that a sharp leading edge on -the cap in the
32 direction of rotation does not exist, -thereby preventing the
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1 I caps from peeling off due to a wedging of scrap material
2 if thereunder. The raised outer portions of the discs (or
I shoulders) may be made in any particular configuration
4 ¦! necessary to hold the cap in position. In an alternate
Lyle embodiment, the disc groove and central cap protrusion are
6ii` designed to insure a tight fit there between and impact
7, absorption by the disc shoulder. Also, a tongue-and-groove
I may be located between the cap and the disc to prevent lateral
Lowe movement of the cap. Once the cap becomes work hardened in
10ll position, there is very little or no need to further tighten
the caps in position.
12 if The use of the caps on the discs greatly reduce the
isle need for periodic rebuilding of the discs or the replacement
I Of the discs due to wear. Presently, there is a significant
15¦l amount of downtime due to rebuilding of discs or replacement
16¦ of caps anchored to the pins. By use of the present system,
17 1¦ there is less downtime and increased capacity from the
18l~ hammer mill. Nevertheless, the caps and discs can be
I easily replaced.
20 1¦ As an additional feature, by using a dual feed roller
21 i¦ which is anchored on a pivot point near the inlet for
Lowe the hammer mill, which dual feed roller may pivot upward
23 Al onto an automobile body being fed into the shredder,
24¦ll a more uniform feeding of an automobile body is provided.
25 if The first roller crushes the automobile body inward
Lowe with the second roller completing the crushing. As an
27 if, automobile body is fed into the shredder and is impacted
28 I by the hammers, knobs on the rollers keep too much of
29 ' the automobile body from feeding into the shredder at
one time, thereby insuring a more uniform feed into the
31 shredding apparatus and maximizing the efficiency and
32
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' capacity of the shredder. By having a more uniform feed, ,
Al it is not necessary to have as much power, thereby increasing
3 if the efficiency of the hammer mill.
4 I DESCRIPTION OF THE DRAWINGS
I Fig. 1 is a pictorial representation of a hammer mill
Al utilizing the present invention with a portion of a housing
7 l¦ of the hammer mill being cut away for illustration purposes.
8 if Fig. 2 is a pictorial side elevation of a hammer mill
9'1 utilizing the present invention with a portion of the
Al housing being cut away for illustration purposes, and
illustrating the raising of a hood of the housing for access
12 Al to a rotor contained therein.
13l Fig. 3 is a pictorial side elevation view of a hammer
14l mill utilizing dual feeder rollers.
15l' Fig. 4 is a perspective view of a rotor having capped
16 l¦ discs thereon prior to installation.
17 if Fig. 5 is a front elevation view of Fig. with a
18 if portion being sectioned along section lines 5-5 of Fake. 6.
19 Jo Fig. 6 is a sectional view of Fig. 5 along section
20 11 lines 6-6.
21,l Fig. 7 is a partial sectional view of a disc and
22j caps of a rotor in operation illustrating an alternative
23¦, method of connection of the caps.
24l, Fig. 8 is a side elevation view of an alternative cap.
25l1 Fig. 9 is a partial pictorial and sectional view
26 , illustrating an alternative cap and disc.
27 I Fig. 10 is an exploded perspective view of a single
I ' disc as installed with a cap exploded therefrom.
29 I Fig. 11 is a plan view of an alternative capped disc
with an alternative cap exploded therefrom.
31 Fig. 12 is a partial sectional view of the alternative
32 capped disc as shown in Fig. 12.
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Al DESCRIPTION OF THE PREFERRED EMBODIMENT
2 if Referring now to Fig. 1 of the drawings in combination
3~,1 with Fig. 2, a hammer mill is shown represented generally by
4.Z reference numeral 10. The hammer mill 10 has a feed ramp 12
Al through which materials to be shredded, such as automobile
6 body 14, are fed into the hammer mill 10. Feed rollers 16
Al and 18 feed the automobile body 14 into the hammer mill 10
8 if through opening 20.
isle The hammer mill 10, which has a rotor 22 located
therein turning at a high rate of speed from a drive
11,l connection to a motor (not shown), is enclosed by housing
12 if 24. The housing 24 has a hood 26 which covers the upper
13 I portion of the rotor 22. The rotor 22 has a plurality of
14¦l discs 28 mounted on a shaft 30 that is turned by the power
15 I source (not shown). Located intermittently between the
16 ill discs 28 are hammers 32, which hammers 32 are free to rotate /
17 if as well as the rotation of the rotor 22. ,
18 if As the rotor 22 rotates and scrap metal, such as
19l automobile body 14, are fed into the hammer mill 10, the
20 if hammers 32 impact against the automobile body 14. Between
21 I the hammers 32 and anvil surface 34, the automobile body 14
22 It is shredded into small pieces. The shredded material is I,
23 lo discharged from the rotor area through either lower grate 36
24l~ or upper grate 38. The lower grate 36 has a finer mesh than .
I " the upper grate 38. However, the impacting of the hammers 32
26 If against the material being shredded will knock some of the
27 material upward through upper grate 38, which shredded
28 material is reflected off of walls 40 and 42 of -the hood 26
29. and falls downward behind dividing wall 44. The material.
30 which has been shredded that either falls through lower
31 grate 36, or is knocked through upper grate 38 and falls
32 behind dividing wall 44 lands on a conveyor 46. Conveyor 46
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lit moves the shredded Inaterial to the right as shown in Fig. 1
I and dumps the material on another conveyor 48. A suction
3 i hood 50, which is connected to a vacuum source (not shown),
4l3 draws the lightweight particles (such as plastics, foam,
5l1 dirt, etc.) up through conduit 52 as the shredded material
6 i is dumped from conveyor 46 on the conveyor 48. Conveyor 48
7~1 takes the heavier shredded particles away for further
8 I processing.
Gil In the event that some portions of the material to be
10!1 shredded are broken off in large chunks that are difficult
11,,! or impossible to be discharged through lower grate 36 or upper
12 if grate 38, gate 54 contained on gate pin 56 may be opened
13 1 (as shown in Fig. 1) to discharge the larger objects there- !
14 if through. The operating mechanism for the gate 54 may be of
15,1 any conventional means, such as a hydraulic cylinder 58 as
16 l shown on Fig. 2.
17 'if Referring now to Fig. 2, the same numerals as used in
18 I describing Eye. 1 will again be used. However, in Fig. 2,
19 ¦ material to be shredded is not being fed into the hammer
20 I mill 10, even though arrows indicate the direction the
21 If material being shredded as well as the direction of the
22 1! parts for the hammer mill 10 will be moving.
23 ill Referring to the feed rollers 16 and 18, they are both
24 I, mounted on a support bracket 60 (a portion of which is
25 I cut away) that is pivotal connected by pin 62 to anchor
26l~ support 64. Support bracket 60, which is located on either
27l side of the feed ramp 12, has a shaft 66 extending there-
28 1 across for supporting feed rollers 16 and a shaft 68 extending
29, there across for supporting feed roller 18, respectively.
Also carried on the support bracket 60 is a drive mechanism
31 70 (such as a motor), which drive mechanism 70 is used to
32 turn drive sprocket 72. Drive sprocket 72 through chains 74
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Al and 76 turns sprockets 78 and 80, respectively. Because
2jj sprockets I and 80 are connected to shafts 66 and 68,
I respectively, they likewise turn feed rollers 16 and 18,
Gil respectively. While the feed rollers 16 and 18 turn on
51~ shafts 66 and 68, respectively, both may pivot about pin 62
I in a manner as will be further described in conjunction with
7j, Fig. 3. The rollers 16 and 18 have longitudinal ribs 84
I extending there across, as well as intermittent spikes for
I digging into the material to be shredded.
10l1 As the rotor 22 turns during actual operation of the
11i~ hammer mill 10, the hammers 32 sling outward in a manner as
12jj shown in Fig. 2. On the individual discs 28 of the rotor 22
131j are located caps 86 around the outer periphery thereof.
141ij These caps will be explained in further detail in connection
15'j with Figs. 4-12~ The gate 54 is held in its closed position
16i¦ by hydraulic cylinder 58 until such time as gate 54 needs to
17 j be opened to discharge large items from thy hammer
lo mill 10. If access is needed to the rotor 22, the hood 26
19 if may be raised by activating hydraulic cylinder 88 to the
20i, position as shown in reference lines. Naturally this would
21 I first require removing any bolts or other securing devices
22,jl (not shown) that would hold the hood 26 in its normal operating
23 j position. Hood 26 will rotate upward upon activation of the
24l, hydraulic cylinder 88 about pin 90. The raising of the hood
25~l 26 allows access to the internal portion of the hammer mill
26 , 10 for any repairs or other work that may need to be performed.
27 l¦ Referring now to Fig. 3, the feed rollers 16 and 18 are
28 explained in further detail. As the automobile body 14 is
29 fed along feed ramp 12, feed roller 16 through the spikes 82
30 , and rips 84 will grab the automobile body 14. Due to the
31 , downward pulling action of hydraulic cylinder 92, (or the
32 '
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Liz, sheer weight of the rollers 16 and 18 themselves), the feed
2¦Z roller 16 will tend to crush the automobile body 14. Feed
I roller 18 tends to further crush the automobile body 14.
Al The ribs 84 and spikes 82 prevent too much of the automobile
5 if body 14 from feeding into the hammer mill 10 at one time.
6 lo While the feed rollers 16 and 18 are turning on their
7 if respective shafts 66 and 68, if the feed rollers 16 or 18
8 if have problems crushing -the automobile body 14 (or any other
gull material being fed into the hemmer mill 10), they may pivot
10 Al¦ about pin 62 with the entire bracket support 60 rotating
upward as shown in reference numerals to provide extra
12~l clearance. 'viny this occurs, hydraulic cylinder 92 which is Z
13 Al attached to bracket support 60 by means of pin 94 and to an
14l~ anchor support 96 tends to pull the bracket 60 and its
15 Al respective feed rollers 16 and 18 downward. This allows
16~l some flexibility to the material being weed into the hammer 1.
17 if mill while simultaneously providing a compression or compacting
of the material to be shredded. It is much easier to compact
19l material, such as automobile bodies, in steps by two rollers,
20 if such as feed rollers 16 and 18, than it is to feed the
21 . material into the hammer mill 10 by a single stationary feed
22~ roller.
23~l Referring now to Fig. 4 of the drawings, the rotor 22
24~' its shown yin further detail. In Fig. 4, the rotor 22 is not
25 1 installed with the hammers 32 on hammer pins 110 (described
26 I subsequently herein) being partially extended for pictorial
27 purposes. The discs 28 each have a plurality of the caps 86
28 located there around with a typical number being either four
29 1 or six depending upon the type of rotor. The caps 86 have
30 recessed bolt holes 98 extending radially inward, which
31 recessed bolt holes 98 align with radial bolt holes 100 (not
32 shown in jig. 4) of discs 28. Intersecting the radial bolt
11
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I holes 100 in the discs 28 are slots 102 in which nuts can be
2 , attached to bolts (shown hereinafter) extended through
I recessed bolt holes 98 and radial bolt holes 100 to secure
Al the caps 86 in position. As explained hereinbelow,
Al, the hot holes may also extend perpendicularly inward.
6 , The entire rotor 22 is turned by means of -the shaft 30,
7j~l which is held in position by bearings 104 located on either
8 1 end of the shaft 30. The discs 28 and any end plates
Eli (shown in Fig. 5) that may be used are held in position by
10 l¦ disc bolts 106 and nuts 108. The disc bolts 106 extend
11l through all of the discs 28 that are mounted on the shaft 30
12`l for the rotor 22.
13 I Referring now to Fig. 5, a partially sectioned elevated
14 side view of the rotor 22 as shown in Fig. 4 is illustrated.
15,l The disc bolts 106 can be seen to extend rough all owe the
16,l discs 28 with -the nuts 108 being secured to either end
17 Al thereof. Referring to Figs. 5 and 6 in combination, it is
18~1 shown -that hammer pins 110 extend through holes 112 near the
19l~ outer circumference owe the discs 28. The hammer pins 110
20ll may be held in position by any convenient means, such as end
211 plates 114, which abut against the respective ends of the
22 if hammer pins 110 and are held in position by disc bolts 106
23~, and nuts 108. However, it should be realized that any of a
24 l number of methods could be used to secure the hammer pins
25 l 110 in position. If end plates 114 are used, the caps 86
26 ' as located on the end discs should be wider to also cover
27 the end plates 114.
28 Located between the various discs 28 are pin spacers
29 . 116, which both protect the hammer pins 110 and provide the
proper spacing between the discs 28. A-t predetermined
, .
31 locations along the hammer pins 110, the pin spacer is
32; eliminated and a hammer 32 is inserted. The hammer 32 is
12
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Al free to rotate on the hammer pin 110. Caps 86 cover the
I entire periphery of the discs 28 as can be more clearly
I seen in Fig. 6.
I!
4ii In Fig. 6, which is a cross-sectional view of Fig. 5
Al along section lines 6-6, a better understanding of the
6~1 connection of the caps 86 tote discs 28 can be obtained.
I It is suggested that Fig. 6 be viewed in conjunction with
Al the partial exploded view as shown in Fig. 10. The caps 86
91l are attached by bolts 118 through the recessed bolt holes 98
10 it and radial bolt holes 100 to nuts 120 located in slots 102.
11~i Each of the caps go has at least one recessed bolt hole 98
12(~l located at zither end thereof for securing -the cap go
13~, to the discs 28. Between each of the respective caps 86
14~ are slanting cuts 122 so that each cap 86 will fit in with
15'l the adjoining cap in a ship lap manner. Each cap 86 covers
16 it, a radial arc ox the discs 28 until -the entire disc 28 is
17 covered by caps 86. The caps 86 are made from a work
18 if hardening type of material, such as manganese or a
19l manganese alloy. A typical material would be an austenitic
20 ill manganese steel, or other type of alloy steel having
21 Zip similar characteristics, from which the cap 86 could be made. Z
22 I The longer a work hardening material is used, the harder
231l the material becomes. However, during the work hardening
24i process, -the material (caps 86) tends to be ductile and must
25~ be securely fastened into position by the bolts 118. Since
I the bolts 118 have an Allen type head and the nuts 120 are
27, accessible, or are held in position by the sides of slots
28 102, the bolts 118 may be tightened after a short period
29 of use.
I.
Also as can be seen in Fig. 6, the holes 112 for the
31 hammer pins 110 are larger than necessary for the hammer pins
32 110 to extend there through. When in operation, the hammer
13
I
I pins 110 with the hammers 32 will extend radially outward;
Al, however, the enlarged hole 112 will allow the hammer pin 110
Al, to bounce back to a slight degree in the event that an
4,1 exceptionally difficult item to shred is struck by the
I hammers 32.
6 If To prevent the entire impact force as exerted on caps
7 If 86 by shredded materials during the shredding process from
I being borne by bolts 118, an outward protrusion 124 of the
Gil discs 28 is provided at every location for hammer pins 110.
10,l By having the outward protrusion 124, the leading edge or
11,~ shoulder 126 of the discs 28 will absorb the impact as
12 I received by the shoulder 128 of cap 86 created by undercut
131 130. It should be realized that undercut 130 of cap 86
14l, should match -the outward protrusion 124 of discs 28. It I,
15 if should be realized (as will be explained in more detail
16 if subsequently) that the undercut 130 of the cap 86 or the
17 1 outward protrusion 124 of the discs 28 may vary, but the
18~¦ most important aspect is to have a leading edge 126 of -the
19 discs 28 which may receive the impact against the cap 86
20l~ via shoulder 128.
21 I To keep the discs 28 from spinning on the shaft 30,
22 it keys 132 are located there between. Also, internal spacers
23 1! 134 (see Fig. 5) are located between respective discs 28
Al except between the center disc where the shaft 30 is enlarged
25l to provide shoulder 136 as shown in Fig. 5.
26 if By having the caps 86 connected as shown in Fig. 6 to
27 ,' the discs 28, the outward leading edge 138 always forms an
28 , obtuse angle to the direction of rotation of the rotor 22.
29 Likewise, the outward trailing edge 140 of the cap 86 always
forms an acute angle. This prevents any materials from
31 getting wedged under the leading edge of the cap 86 which
32 ; would have a tendency to tear the cap 86 off of the discs
14
issue
I 28.
3 i Referring -to Fig. 7, a partial sectional view of a
Al capped disc during operation is illustrated with the hammers
5 if 32 being fully extended due to the rotational force of the
6Ij rotor 22. The disc 28 has caps 86 attached thereto. The
Al, hammer pins 110 are extended radially outward inside of
8 If holes 112 due to the rotational inertia. In addition to the
91l previously described bolts 118 extending through recessed
10l¦ bolt holes 98 and radial bolt holes 100 to cross slots 102
11 for connecting to nuts 120, Fig. 7 further illustrates the
12 If use of center bolt 142 to protect the slanting cut 122
13 I between adjoining caps 86. The center bolt 142 has a
14~l recessed bolt hole 144 that aligns with radial bolts hole
15 1 146 in a lower cap 86 and with radial bolt hole 148 in the
16~¦ discs 28. Again, a slot 150 intersects the radial bolt hole
17l~ 148 so that a nut 152 can be attached to center bolt 142.
18¦l By use of the center bolt 142 in addition to the previously
19~l described bolts 118, additional integrity is provided to the
20 it cap 86 -to insure that caps 86 do not separate during use.
21l Referring now to Fix. 8, a modified cap 154 is shown.
22 11 The modified cap 154 again has recessed bolt holes 98 located
23l~ in either end thereof for accepting the bolts 118 as previously '
24 l described. However, the undercut 130 has been replaced with
25, undercut 156 that has rounded front shoulder 158 therein.
26' The rounded front shoulder 158 provides more of an impact
27' surface between the modified cap 154 and the discs (not
28~~ shown in Fig. 8j to help eliminate the force from shredded
29~ material from being exerted on the bolts 118. Obviously,
30~( the discs wised in conjunction with the modified cap 154
31 would have to be likewise contoured to provide a matching
32 rounded front shoulder to abut against rounded front shoulder
:~35~
Al 158 of modified cap 154.
Al Referring now to Fig. 9, a second modified cap 160 is
3 I shown. The modified cap 160 is attached to the discs 28 in
of the normal manner by bolts extending through recessed bolt
I holes 98 as previously described. Also, the discs 28 have
I an outward protrusion 124 and the modified cap 160 has a
I' matching undercut 130 to accept the outward protrusion 124.
8 if However, between the modified cap 160 and the discs 28 are
91 located a tongue 162 and groove 164 to form a tongue and
10~, groove connection. While the tongue 162 is shown as part of
11i, the discs 28 and the groove 164 is formed as part of the
12 I, modified cap 160, obviously these can be reversed. The
13 I object is to provide an internal radial overlapping between
14 f the modified cap 160 and the discs 28 to prevent the modified ,
15, cap 160 from moving to the right or left of the discs 28. ,
16~lf During the period of time that the modified cup 160 is work
fly hardening in position, it has a tendency to be dl1ctile and
18 I may bend to the right or left of the discs 28. By the use
fly owe the -tongue and groove arrangement as shown in Fig. 9, or
20ll any other suitable radial overlapping, the bending or
21 'If shaping of the modified cap 160 has been eliminated. While
22 i this has not been shown to be a particularly significant
23 " problem, such an overlapping arrangement could prevent the
24, problem from occurring.
25 'I Referring now to Fig. 11, an alternative capped disc
26 I' 170 is shown for use in conjunction with the aforementioned
27 rotor 22 and shaft 30. The capped disc 170 includes a
28 l third modified cap 172 which is attached to a modified
29 disc 174 by bolts 176 extending trough recessed bolt holes
30l 178 located at or near the center of cap 172, as illustrated
31 ion Fig. 12. As further illustrated in Fig. 12, recessed bolt
32 holes 178 extend perpendicularly inward and align with
'
16
~Z~54~)6
perpendicular bolt holes 180 of disc 174. Intersecting the
perpendicular bolt holes 180 in the disc 174 are slots 182
in which nuts 184 can be attached to the perpendicular
bolts 176.
Modified cap 172 has an inward protrusion 186 having
an edge or border 188 perpendicular to bolts 176 and bolt
holes 178 and 180. Modified disc 174 has a complimentary
groove 190 for receiving inward protrusion 186 having an
edge or border 192 perpendicular to bolts 176 and bolt
holes 178 and 180. Modified disc 174 has peaked outward
protrusions 194 periodically there around and each cap 172
has a complimentary wing 196 on each end thereof adapted
to match with and overlap the facing halves of successive
outward protrusions 194. As illustrated most clearly in
Fig. 12, each wing 196 sits slightly apart from its
matching protrusion 194 leaving a gap 198 there between
when cap protrusion 186 is received by disc groove 190.
This design assures a tight fit between perpendicular
mating surfaces or borders 188 and 192. Cap 172 has a
generally arcuate outer surface 193, a leading edge or
surface 195, on the leading end of cap 172 upon rotation
of cap 172, at an obtuse angle relative to outer surface
193, and a trailing edge or surface 197, on the trailing
end of cap 172 upon rotation of cap 172, at an acute angle
relative to outer surface 193. The trailing edge or
surface 197 of a cap 172 will overlap the leading edge or
surface 195 of an adjacent cap 172 when a plurality of
caps 172 are attached to disc 174.
As illustrated in Fig. 12, the contour of inward
protrusion 1~6 and groove 190 creates a mating surface 200
between rounded undercut 202 on the trailing end of cap 172
and rounded shoulder 204 in disc 174 when protrusion 18
17
~2~5~6
is received by groove 190. Mating surface 200 is
substantially perpendicular to the direction of rotation
of disc 174, as illustrated by the arrows in Fig. 11 and
Fig. 12~ In this embodiment, leading disc shoulder 204
absorbs substantially all of the impact against cap 172
during the operation of the hammer mill 10. The opposite
undercut 206 on the leading end of cap 172 is appropriately
angled to leave a gap 208 between angled cap shoulder 210
and rounded leading disc shoulder 212. This design also
10. assures a tight mating engagement between perpendicular
surfaces 188 and 192.
As illustrated in Fig. 11, the modified disc 174
includes pin holes 112, disc key slots 214 for keys 132,
aye
I and disc bolt holes 216 for disc bolts 106. In this
2 if embodiment, -the cap 172 can be made from a work hardening
3 if material such as manganese, and the number of caps 172
can be increased such that two caps 172 are provided for
5 I each one of the pin holes 112.
6 if While i-t is envisioned that the caps as previously
7 I described hereinabove will normally be installed on new
if rotors fur hammer mills, rotors for existing hammer mills
g if can be easily modified to provide the capped disc eater
10 Al as described hereinabove. The rotor 22 would have to be
11 i¦ removed from the hammer mill 10 and the discs removed from
12 I¦ the shaft 30. The discs would then either be replaced with
13 I! discs as described hereinabove or reshaped to the same
4 I general shape as -the discs described hereinabove. The
If reshaped discs would have -to have a means for attaching
16 ¦¦ the cap -thereto, such as the radial bolt holes 100 end
17 slots 102. Thereafter, -the caps as previously described
I would be attached to eye discs and the discs reinstalled
19 on the shaft 30. Then the en-tire rotor 22 would be
reinstalled in -the hammer mill 10. Approximately two or
21 l¦ three times during the initial running of the hammer mill 10,
22 Al if bolts are used for attaching the caps to the discs, then
the bolts will have to be tightened. The reason for
I if tightening the bolts is because -the caps are work hardening
25 Al and fitting into position, during which time they have a
6 if tendency to be malleable or ductile.
271, While the invention has been described in connection
I with the preferred embodiments, i-t is not in-tended to limit
29 Lowe the invention -to the particular forms set forth, but on
30 1. the contrary, i-t is intended to cover such alternatives,
31 .. modifications, and equivalents as may be included within
32 the spirit and scope of -the invention as defined by -the
"
appended claims.
