Abstrict A rock crusher comprises a pair of rotors spaced apart to define
a throat therebetween and driven in opposite directions. Impactor
bars on the rotors crush rock that is delivered to the rotors and
passes the broken rock fragments through the throat. The rock crusher
may be conveniently provided in a harvesting vehicle such as a potato
harvester to crush rock that has been picked up with and separated
from the crop. The rocks can be crushed to a sufficiently small
size that they may be conveniently returned to the field surface,
and thus the arrangement avoids the trouble and expense that would
otherwise be entailed in collecting and disposing of the separated
rock.
Claims What is claimed is:
1. A rock crusher comprising:
a frame;
bearing means carried in said frame and mounting a pair of rotors
for rotation about parallel axes and at a predetermined spacing
from each other to define between them a throat that has a width
and a length;
each said rotor carrying a plurality of radially projecting longitudinally
extending impactors, said impactors having a longitudinally extent
equal to at least a part of the length of said throat, the impactors
of each rotor being angularly spaced apart providing clearance therebetween;
drive means connected to rotate said rotors in timed synchronous
fashion but in opposite directions, the impactors of the opposed
rotors being in register so as to pass simultaneously in pairs through
a plane in said throat that extends along said axes of said rotors;
and
a passage for directing rock into said throat to be fractured by
said rotating impactors into fragments of a size sufficiently small
to pass between said rotors.
2. A rock crusher as claimed in claim 1 wherein said drive means
is coupled to apply a driving torque to each end of both of said
rotors.
3. A rock crusher as claimed in claim 2 wherein said driving means
comprises a transmission element of flexible resilient material
at opposite ends of said rotors, each said transmission element
being passed in an endless loop in succession over: a first drive
wheel fixed to rotate with one said rotor; a second drive wheel
fixed to rotate with the other said rotor; and a third wheel that
is mounted to rotate on an axis that is parallel to the axes of
said rotors.
4. A rock crusher as claimed in claim 3 wherein each said transmission
element comprises a flexible toothed belt and said wheels comprise
toothed pinions.
5. A rock crusher as claimed in claim 4 wherein each said belt
is toothed on both sides thereof one side having teeth that engage
with said first drive wheel and said third wheel and the other side
having teeth that engage with said second drive wheel.
6. A rock crusher as claimed in claim 2 including removable wear
plates that are mounted on end walls of the frame and secured by
releasable threaded fasteners.
7. A rock crusher as claimed in claim 2 wherein said drive means
includes a belt driven pulley attached to one of said rotors and
a motor coupled to drive said pulley.
8. A rock crusher as claimed in claim 2 wherein said drive means
comprise fiber reinforced flexible rubber belts cooperating with
toothed pinions on the respective opposite ends of said rotors to
drive the rotors in timed synchronous manner.
9. A rock crusher according to claim 8 wherein each said belt is
passed in an endless loop in succession over a first gear fixed
to rotate with one said rotor, a second gear fixed to rotate with
the other said rotor and a third gear fixed to rotate with one end
of a common lay shaft that is mounted to rotate on an axis that
is parallel to the axes of the rotors, and further including motor
means coupled to apply a rotary drive to said rotors.
10. A rock crusher as claimed in claim 2 in combination with a
harvester vehicle, said harvester vehicle including means for processing
crop material lifted continuously from the surface of a field, said
vehicle including means for separating rock from such material and
delivering such separated rock to said rock crusher.
11. A rock crusher as claimed in claim 1 wherein each said impactor
comprises a breaker bar of high strength impact resistant material,
said impactors being detachably connected to said rotors.
12. A rock crusher as claimed in claim 6 wherein each impactor
is attached to a carrier plate that in turn is adapted to be detachably
connected to the rotor.
13. A rock crusher as claimed in claim 7 wherein the peripheral
surface of each said rotor is substantially completely shielded
from wear by the associated carrier plates.
14. A rock crusher as claimed in claim 13 wherein each rotor is
of generally square cross section and is adapted to support four
carrier plates arranged successively at right angles and each extending
over at least a major portion of the length of the throat.
15. A rock crusher as claimed in claim 13 wherein each said impactor
comprises a plurality of sections arranged end-to-end and having
a combined length substantially equal to that of said throat.
16. A rock crusher as claimed in claim 12 including screwthreaded
fastener means adapted to detachably connect each carrier plate
to its rotor, said rotor and said carrier plates having complementary
formations defining interengaging confronting surfaces that extend
at least partially in the radial direction relative to the rotor
axis and that function to shield said threaded fastener means from
loading in shear.
17. A rock crusher as claimed in claim 16 wherein said interengaging
formations comprising interengaging rib and groove means on said
rotor and said carrier plate, said rib and groove means extending
in the longitudinal direction of the rotor.
18. A rock crusher as claimed in claim 12 wherein each breaker
bar is attached to its carrier plate by welding and is of rectangular
profile and is oriented with said rectangular profile oblique to
a radial plane of the associated rotor to present a leading corner
in the direction of rotation.
19. A rock crusher as claimed in claim 11 wherein each impact or
is formed integrally with a carrier plate that is detachably connected
to the rotor.
20. A rock crusher as claimed in claim 19 wherein said carrier
plates in combination substantially completely shield the peripheral
surface of each rotor throughout the length of said throat.
21. A rock crusher as claimed in claim 19 wherein said rotor and
said carrier plates have complementary formations defining interengaging
confronting surfaces that extend at least partially in the radial
direction of the rotor to transfer impact loading forces from the
breaker bars to the rotor.
22. A rock crusher as claimed in claim 1 in combination with a
motor driven mobile vehicle, the motor of said vehicle providing
power for driving said rock crusher.
23. A rock crusher as claimed in claim 1 in combination with a
vehicle that includes means for lifting surface material including
rocks from the surface of a field and separating means for separating
said rocks and delivering them to the rock crusher.
24. The combination of claim 23 wherein said rock crusher is adapted
to be driven by a hydraulic motor coupled to a hydraulic system
of said vehicle.
25. A rock crusher as claimed in claim 1 further comprising an
anvil in the form of a rigid bar supported in said frame in the
region immediately below and extending generally parallel to said
throat said anvil being adjustable towards and away from said throat.
26. A rock crusher comprising:
a frame;
bearing means carried in said frame and mounting a pair of rotors
for rotation about parallel axes and at a predetermined spacing
from each other to define between them a throat;
each said rotor carrying a plurality of radially projecting longitudinally
extending impactors, the impactors of each rotor being angularly
spaced apart providing clearance therebetween;
drive means connected to rotate said rotors in timed synchronous
fashion but in opposite directions so that the impactors of the
opposed rotors pass in pairs through said throat at the same time;
said drive means comprising a transmission element of flexible
resilient material at opposite ends of said rotors, each said transmission
element being passed in succession over: a first drive wheel fixed
to rotate with one said rotor; a second drive wheel fixed to rotate
with the other said rotor; and a third wheel fixed to rotate with
a respective end of a common lay shaft that is mounted to rotate
on an axis that is parallel to the axes of said rotors; and
means for directing rock into said throat to be crushed and passed
through said throat by said rotating impactors.
27. A rock crusher as claimed in claim 26 wherein each said transmission
element comprises a flexible toothed belt and said wheels comprise
toothed pinions.
28. A rock crusher comprising:
a frame;
bearing means carried in said frame and mounting a pair of rotors
for rotation about parallel axes and at a predetermined spacing
from each other to define between them a throat;
each said rotor carrying a plurality of radially projecting longitudinally
extending impactors, the impactors of each rotor being angularly
spaced apart providing clearance therebetween;
drive means connected to rotate said rotors in timed synchronous
fashion but in opposite directions so that the impactors of the
opposed rotors pass in pairs through said throat at the same time;
wherein said drive means is adapted to apply a driving torque to
each end of both of said rotors and comprises a pair of flexible
toothed belts of reinforced rubber composition which cooperate with
toothed pinions carried at the respective ends of each said rotor;
and
means for directing rock into said throat to be crushed and passed
through said throat by said rotating impactors.
29. A rock crusher as claimed in claim 28 in combination with a
vehicle that includes lifting means for lifting surface material
including rocks from the surface of a field, and separating means
for separating said rocks and delivering them to said rock crusher.
30. A rock crusher comprising:
a frame;
bearing means carried in said frame and mounting a pair of rotors
for rotation about parallel axes and at a predetermined spacing
from each other to define between them a throat that has a width
and a length;
each said rotor carrying a plurality of radially projecting longitudinally
extending impactors, said impactors having a longitudinal extent
equal to at least a major part of the length of said throat, the
impactors of each rotor being angularly spaced apart providing clearance
therebetween;
drive means connected to rotate said rotors in timed synchronous
fashion but in opposite directions, the impactors of the opposed
rotors being in register so as to pass simultaneously in pairs through
a plane in said throat that extends along said axes of said rotors;
and
a passage for directing rock into said throat to be fractured by
said rotating impactors into fragments of a size sufficiently small
to pass between said rotors.
Description BACKGROUND OF INVENTION
(a) Field of the Invention
This invention relates to a new or improved rock crusher, particularly,
but not exclusively to a rock crusher suitable for incorporation
in an agricultural harvesting vehicle such as a potato harvester
to crush rock which has been taken up from the field surface along
with the crop.
(b) Description of the Prior Art
In potato harvesters the rocks separated from the crop, should
preferably be removed rather than simply being returned to the field.
Hitherto this has entailed collecting the rocks in a box on the
harvester and periodically removing them, by dumping them in a pile
in the field for subsequent disposal by another vehicle. This method
is clearly inefficient, and furthermore since it increases compaction
of the soil because of the increased traffic necessary for collection
and disposal of the piles of rock, in the long run it will decrease
the productivity of the land. U.S. Pat. No. 4417627 shows an apparatus
that includes a work shaft having prongs and a rotatably driven
drum on which flail-like parts are mounted whereby rocks lifted
and pre-crushed by the rotary motion of prongs on the work shaft
are broken by impact by the flail-like parts of the rotating drum.
The prior arrangements are designed as separate machines to crush
rocks in an agricultural field. The high speed impact breaking of
rocks on the ground employed by prior art machines also breaks the
structure of the soil. Use of a rock crusher mounted on a harvester
in stony potato fields is more desirable since crushing of rocks
can be achieved above the ground and in the same operation as harvesting.
SUMMARY OF THE INVENTION
The present invention provides a rock crusher comprising: a frame;
bearing means carried in said frame and mounting a pair of rotors
for rotation about parallel axes and at a predetermined spacing
from each other to define between them a throat; each said rotor
carrying a plurality of radially projecting longitudinally extending
impactors, the impactors of each rotor being angularly spaced apart
providing clearance therebetween; drive means connected to rotate
said rotors in timed synchronous fashion but in opposite directions
so that the impactors of the opposed rotors pass in pairs through
said throat at the same time; and means for directing rock into
said throat to be crushed and passed through said throat by said
rotating impactors.
The drive means is preferably in the form of a pair of flexible
reinforced rubber double-sided tooth belts each of which is trained
in a continuous loop and contacts toothed wheels or pinions that
are keyed to the respective rotors, the path of the belts being
such as to rotate the rotors in opposite directions.
The impactors may be in the form of breaker bars detachably connected
as by welding on mounting plates that are releasably secured to
the rotor by recessed cap screws. However, preferably the breaker
bars are formed integral with the mounting plates in unitary structures.
There preferably are interengaging formations such as complementary
ribs and grooves between each mounting plate and the rotor to absorb
impact loads thus preventing damage to the cap screws. The mounting
plates altogether preferably enclose the entire periphery of the
rotors so that the surface of the latter is entirely shielded from
abrasive wear.
Replaceable wear plates of impact and abrasion resistant steel
are preferably provided on the internal surfaces of the housing
of the crusher at the locations most subject to wear, i.e. on the
end walls adjacent to the ends of the rotors.
The rock crusher can be operated from any convenient power source,
e.g. gasoline or diesel engines or hydraulic or electric motors.
While in stationary installations electric drive motors may be suitable,
in mobile applications, such as in crop harvesting vehicles it will
be more convenient to power the rock crusher from either a mechanical
or fluid power take-off from the vehicles main systems, or by means
of a separate engine.
DESCRIPTION OF THE DRAWINGS
The invention will further be described, by way of example only,
with reference to the accompanying drawings in which:
FIG. 1 is a somewhat schematic front elevation of a rock crusher
in accordance with the invention;
FIG. 2 is a side view corresponding to FIG. 1;
FIG. 3 is an enlarged fragmentary sectional view taken on the line
A--A in FIG. 1;
FIG. 4 is an exploded front elevational view of a rotor of the
rock crusher shown with impactor bars detached from the rotor;
FIG. 5 is a partially exploded end view of the rotor and two impact
or elements;
FIG. 6 is a partially exploded view showing an alternative form
of rotor assembly; and
FIG. 7 is a generally schematic view illustrating the rock crusher
as provided in a potato harvester.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As seen in FIG. 7 a potato harvesting machine 5 of generally known
construction includes a rock crusher 10 mounted thereon to receive
rocks and other debris which the harvester separates from potatoes
that are lifted from the surface of the field. As will be described,
the rock crusher 10 fractures and fragments these rocks, returning
them to the field surface where they have beneficial effects on
the quality of the soil.
The rock crusher as seen in FIGS. 1 to 3 comprising a housing generally
indicated at 10 in the form of a steel casing defining a vertically
arranged rectangular passage 11 the upper end of one major vertical
side thereof defining a large rectangular inlet opening 12 which
is curtained by a series of closely spaced suspended chain lengths
13 the lower ends of which extend below an angled lip section 14
of the inlet opening.
At the lower end of the housing is an enlarged crushing section
15 (see FIG. 3), in which are arranged two parallel horizontal rotors
16a, 16b defining between them a narrow throat 17 the construction
of the rotors being more clearly illustrated in FIGS. 3 through
5.
As best seen in FIG. 4 each rotor comprises a unitary steel shaft
having a central section 20 of generally square profile and reduced
end sections 21 22 of cylindrical form, each having an axially
extending keyway, 21a, 22a respectively, and the end section 21
of the rotor 16a being substantially longer than section 22. The
end sections 21 22 of the rotor 16b are substantially equal. The
profile of the central section 20 of each rotor is most clearly
shown in FIG. 5 as comprising four flat identical elongate faces
23 arranged in a square pattern, each face having a projecting rectangular
rib 24 extending throughout the full length of the central section
20. As shown, the rib is offset towards one edge of the associated
face 23 this edge being referred to as the trailing edge, considered
in respect to the direction of rotation of the rotors as seen in
FIG. 3. Additionally, a pair of axially spaced screwthreaded bores
25 open from each of the faces 23 the bores being symmetrically
positioned in each face and separated by a spacing that is approximately
equal to half the length of the rotor central section 20. The bores
25 are positioned between the leading edge of the face 23 and the
rib 24.
Each face 23 of the rotor is covered in use by a detachable rectangular
mounting plate 26 which is formed with a longitudinally extending
groove 27 complementary to the rib 24. The plate 26 has an area
that completely covers the corresponding face 23 of the rotor. As
clearly shown in FIGS. 3 and 5 the rear edge (considered in the
direction of rotation) of the plate 26 coincides with the rear edge
of the face 23 whereas the forward edge of the plate 26 projects
forwardly of the forward edge of the face 23 and overlaps the rear
edge of the preceding plate 26. The plate 26 furthermore has a pair
of countersunk bores 28 positioned to register with the screwthreaded
bores 25 in the rotor, and at the leading longitudinal edge the
mounting plate carries an impactor bar 29. As shown, the impact
bar 29 is of rectangular profile and is obliquely arranged, being
seated on an angled surface 30 at the leading edge of the mounting
plate and affixed thereto by welding beads 31a, 31b.
As seen in FIG. 3 and 5 the mounting plates 26 are releasably
attached to the rotors 16a, 16b by threaded capscrews 32 passed
through the bores 28 and engaged in the screwthreaded bores 25
the heads 33 of the capscrews being received in the countersunk
portion of the bores 28 so that they do not project significantly
above the outer surface of the mounting plates 26. The arrangement
of the ribs 24 on the rotor cooperating with the complementary grooves
27 in the mounting plates 26 provide a large area surface to absorb
and transmit impact loads between the impact bars 29 and the rotors
16a, 16b so that these loads are safely absorbed. Furthermore it
will be noted that these interengaging formations serve to shield
the capscrews 32 from any shear loads so that they are loaded essentially
only in tension.
As will be understood from a consideration of the foregoing description
in conjunction with the drawings, each mounting plate 26 extends
over the entire length of the square central section 20 of the rotor,
this length corresponding to the length dimension of the crushing
section 15 of the machine. It would of course be possible to provide
a mounting plate that is longitudinally divided into a number of
individual sections (not shown), and in that event additional threaded
holes 25 cap screws 32 and countersunk bores are necessary to ensure
that each section is securely attached to the rotor.
The impactor bars 29 extend longitudinally over at least the major
part of the length of the central section 20 of the rotor. The impactor
bar 29 shown at the upper side of FIG. 4 is continuous over the
full length of the mounting plate 26. In the alternative arrangement
shown in the lower side of FIG. 4 the impactor bar may be fabricated
as a series of shorter sections 29a arranged end-to-end and secured
to the mounting plate 26 as before by welding beads 31a, 31b as
seen in FIG. 5. The sections 29a together have a length corresponding
to at least the major part of the length of the crushing section
15. As shown the impactor bar sections 29a are butted end-to-end,
although they could be separated from each other by narrow gaps.
The length of each section 29a can be varied widely, and preferably
is not less than the radius of the impactor bar from the axis of
the respective rotor 16a, 16b. In any event the impactor bar sections
have a length in the longitudinal direction of the rotor that is
at least three times greater than the distance of the maximum radial
projection of the impactor bar beyond the base of the the mounting
plate 26.
When all four mounting plates 26 are attached to the rotor central
section 20 it will be seen from FIG. 3 that the surfaces of the
latter are completely covered by the detachable mounting plates
26 and that each rotor is provided with four equiangularly spaced
impactor bars 29. The impactor bars register with the corner edges
of the central section 20 and are thus separated by a large angular
clearance.
As shown in FIGS. 1 2 and 3 each rotor is carried in end plates
36 of the crushing section 15 by means of heavy duty sealed roller
bearing assemblies 37 secured to these end plates and engaged upon
the cylindrical portions of the respective ends 21 22 of the rotors
16a, 16b by means of a taper lock adapter sleeve. The rotors are
thus mounted to rotate on parallel axes in the crushing section
15. On the inner side of each of the end plates 36 detachable wear
plates 38a, 38b, 39a, 39b are provided extending from top to bottom
of the end plates in the region between the rotational axes 18a,
18b of the rotors 16a, 16b. These wear plates are secured to the
end plate 36 by countersunk screws 40.
To improve the fragmenting effect of the rock crusher, an anvil
is provided immediately below the throat 17. The anvil is in the
form of a rigid horizontally extending bar 60 of a suitable impact
and abrasive resistant steel that is supported at its opposite ends
in a pair of brackets 61 62 each bracket forming on its upper
side an upwardly open seat. Capscrews 65 extending through suitable
apertures in the brackets engage in threaded bores in the underside
of the anvil bar 60 and secure the ends of the latter to the associated
seat. Each of the brackets 61 62 is in turn supported on an extension
36a of the associated end plate 36. As seen in FIG. 2 each extension
36a has a pair of vertically aligned elongated slots 66 through
which extend capscrews 67 engaged in threaded holes in the brackets
61 62. By loosening the capscrews 67 the associated brackets 61
62 are freed for adjustment vertically relative to the side plates.
Upon tightening of the capscrews 67 the brackets 61 62 and hence
the anvil bar 60 are rigidly secured in fixed relation to the housing.
To ensure that the anvil bar does not move from its selected position
of adjustment, the confronting faces of the extension walls 36a
and the brackets 61 62 have complementary interengaging serrations,
e.g. of a sawtooth profile (not shown).
A drive system for the rotors 16a, 16b comprises a pair of toothed
pinions 41 keyed to the end portions 21 22 of each rotor on the
outboard side of the end plates 36. As seen in FIG. 2 a layshaft
42 is mounted on one side of the crushing section 15 to rotate about
an axis that is parallel to those of the rotors 16a, 16b the mounting
arrangement being schematically illustrated in FIG. 2. A pair of
brackets 45 on the rear wall of the crushing section 15 provide
pivotal mountings 46 which in turn each supports a carrier 47 that
provides a bearing for one end of the layshaft 42. A threaded adjusting
stud 48 carried by the upper end of each bracket 45 is axially adjustable
with respect to a fixed bracket 49 on the crushing section 15.
On each end of the layshaft 42 a toothed idler pinion 50 is keyed
to rotate with the shaft. A flexible transmission element in the
form of a double sided toothed belt 51 passes around each idler
pinion 50 and then extends in an endless loop around both of the
pinions 41 in the path shown in FIG. 2.
Rotation of the rotors 16a, 16b is powered from a motor 52 (FIG.
7) coupled through a multiple belt drive 53 to a grooved pulley
54 keyed to the elongate end portion 21 of the rotor 16a. Alternatively
the drive from the motor 52 could be applied via a grooved pulley
(not shown) on the shaft 42 which in this case would be a drive
shaft rather than a layshaft. It will be appreciated that operation
of the motor 52 and belt drive 53 will be effective to rotate the
two rotors synchronously in timed relation and in opposite directions.
The drive is coupled such that the impactor or hammer bars 29 of
each rotor approach the throat 17 (from the upper side as seen in
FIG. 3) in synchronism.
In operation, with the rotors being driven (in the directions indicated
by the arrows in FIG. 2) at an appropriate speed of rotation, rocks
delivered from the harvester or other vehicle to the inlet opening
12 fall through the vertical passage 11 of the housing towards the
throat 17 and are impacted and fragmented by the rotating bars 29
as the rocks approach the throat. The use of opposed rotors with
impactor bars rotating in synchronism maximizes the fracturing effect
of the latter. As will be understood, the rotors 16a, 16b are driven
in precisely timed synchronized relationship by means of the toothed
belts 51 cooperating with the pinions 41 on the ends of the shafts.
Thus as the rotors rotate, the impactor bars 29 pass in pairs through
the throat 17 i.e. the opposed impactor bars 29 are swing downwardly
and convergently towards the throat 17 to pass simultaneously through
the plane between the rotor axes 18a, 18b. This timed relationship
together with the high inertia of the rotating mass of the two rotors
ensures that massive impact loadings are applied by the compactor
bars to rocks delivered into the crushing section through the vertical
passage 11. The fracturing effect is further enhanced by the addition
of the anvil bar 60 which has the effect of reducing the maximum
size of rock fragments which can pass through the rock crusher.
The rocks are accordingly fractured by the bars and the rock fragments
pass downwards between the rotors to be thrown from the lower end
of the crusher. The chains 13 reduce the likelihood of rock fragments
being ejected through the inlet 12.
The drive to the rotors can be provided in many different ways,
and the motor 52 can be a prime mover such as a gasoline or diesel
engine, or even an electric motor where the rock crusher is provided
in a fixed location. Where the rock crusher is provided on a vehicle
having a hydraulic system, then the motor 52 may conveniently be
a hydraulic motor driven thereby, or by a mechanical power take
off on a tractor.
As will be understood, in operation the components of the rock
crusher, and in particular the rotors and associated parts are subjected
to very high impact loads. It is accordingly important that these
loads can safely be absorbed by the rotors themselves, their bearings,
and by the drive system. Thus the toothed driving belts 51 are of
a fiber reinforced rubber composition and embody a degree of resilience
to absorb the impact load. Such toothed timing belts are commercially
available as supplied by Dodge Engineering. It is important for
the drive to the rotors to be applied from both ends since this
reduces the torsional loading of the rotors and also makes it possible
to deliver the driving torque through two belts. To deliver the
required torque through a single belt would entail the use of a
belt that would be inconveniently wide and difficult to control.
In the configuration shown the drive belts 51 at opposite ends of
the rotors 16a, 16b are synchronized and their loading is equalized
through the idler pinions 50 and the layshaft 42. To transmit the
required high driving forces, the belts 51 are relatively wide.
The tension in each belt 51 is controlled and adjusted periodically
by means of the associated threaded adjusting stud 48.
An alternative rotor assembly configuration is shown in FIG. 6.
The rotor body 70 in FIG. 6 is essentially identical to the body
of the rotors 16a and 16b comprising a unitary steel shaft of the
profile shown. However in the embodiment of FIG. 6 there are provided
unitary impactors 71 which combine the function of the mounting
plate 26 and impactor bars 29 of the previously described embodiment.
As before, each impactor 71 completely covers the corresponding
face of the rotor 70 and projects slightly forwardly therefrom contacting
and covering the trailing edge 72 of the preceding impactor. The
impactors 71 are secured in the same manner as the above described
and are made of materials having the same characteristics. As will
be understood, the unitary impactors 71 each extends longitudinally
over substantially the full length of the rotor in the crushing
section 15 of the machine. The impactor 71 may be continuous as
shown, or may be divided longitudinally into shorter sections. In
either case, a sufficient number and arrangement of fasteners such
as the cap screws 32 are provided to ensure that each impactor or
section thereof is securely attached to the rotor, and yet can be
disassembled when necessary for repair or replacement.
All components of the rock crusher are made from suitable hard,
abrasive and shock-resistant materials. Thus the housing 10 can
be fabricated by welding from steel plates of suitable hardness
and abrasion resistance, e.g. Scandia 400 (Trade-mark) which has
a Brinell hardness of 400. The rotors 16a, 16b are unitary components
formed for example from ASTM-C 1045 steel which has the appropriate
strength and impact resistance for this application. The impactor
bars 29 are suitably made from a low carbon work hardening impact
resistant steel such as Astralloy "V" (Trade-mark) sold
by Hitesi Products Inc. The wear plates 38 39 are also formed from
an impact resistant steel that is hard and highly resistant to abrasion,
e.g. Astralloy "V".
As mentioned earlier, the rock crusher can be provided on a harvester
such as a potato harvester to replace the rock box that was formerly
provided to collect rocks picked up from the field surface along
with the crop. The above described rock crusher being of compact
configuration can be accommodated together with a diesel engine
to drive it, in place of the rock box. The rock crusher is significantly
more efficient than known rock crushers employing rotary driven
hammers or flails cooperating with stationary anvils. For example
the rock crusher of the present invention operates at a greater
efficiency than known single rotor rock crushers in that the dual
rotor design means that the major part of the weight of the rock
crusher is in these moving parts where it can be utilized more effectively
than in stationary anvils. Accordingly more of the energy supplied
to the rock crusher is applied to impacting the rock to be crushed,
and less is lost in friction. The rock crusher of the present invention
is substantially lighter than a single rotor prior art rock crusher
of equivalent capacity since a much greater proportion of the weight
of the new rock crusher is embodied in the rotors rather than in
stationary parts.
A rock crusher of a size suitable to be provided on a potato harvester
machine would have a total weight of approximately 1700 pounds.
This weight is inclusive of the chassis or frame carriage and a
diesel engine that is capable of delivering a continuous output
of 36 horsepower. The drive system is designed to rotate the rotors
at a speed which will vary in the range 800 to 1200 rpm.
Many variations of the details and structure of the rock crusher
will be obvious to those of ordinary skill in the art, and all such
details and modifications are intended to be comprehended within
the scope of the appended claims. |