Abstrict A hammer assembly for a rotary material crusher having a rotor.
The hammer assembly includes a hammer member and a base member.
The base member is mounted at one of its ends on the rotor. The
hammer member is mounted on the other end of the base member. The
hammer member and base member each have two pairs of concave and
convex surfaces, one for absorbing centrifugal forces and the other
for absorbing impact forces and meshing, one surface with the other.
The pair of concave and convex surfaces for absorbing centrifugal
force are behind of the centrifugal force radial line of the hammer
member in the direction of rotation of the rotor.
Claims I claim:
1. A hammer assembly for attachment to a rotor of a rotary material
crusher, said rotor having a plurality of hammer assembly mounting
bases thereon spaced equidistantly around said rotor and adjacent
the periphery thereof, said rotor being rotatable about an axis
of rotation, said hammer assembly including a base member mounted
in a fixed position at one of its ends on a hammer assembly mounting
base on said rotor adjacent the periphery of said rotor so that
said base member does not pivot relative to said rotor, and a hammer
member mounted on another end of said base member, said hammer member
having a first impact surface facing forwardly in the direction
of rotation of said rotor and a second impact surface joined at
one of its edges to an outer end of said first impact surface, said
second impact surface facing outwardly of said rotor, said fixed
member having a first arcuate surface extending parallel to the
axis of rotation of said rotor and facing forwardly in the direction
of rotation of said rotor, and said hammer member having a first
arcuate surface extending parallel to the axis of rotation of said
rotor, said first arcuate surfaces being interengaged with each
other for transmitting the impact forces of said hammer member generated
by the impact of said hammer member with material to be crushed
to said base member, said base member having second arcuate surfaces
extending parallel to the axis of rotation of said rotor and facing
in a radial direction of said rotor towards said rotor, and said
hammer member having second arcuate surfaces extending parallel
to the axis of rotation and facing away from said rotor, said second
arcuate surfaces of said base member being interengaged with the
second arcuate surfaces of said hammer member for transmitting the
centrifugal force of said hammer member generated by the rotation
of said hammer member with said rotor, as said rotor is rotated
at high speed, to said base member.
2. A hammer assembly, as recited in claim 1 in which the radial
axis of said centrifugal force of said hammer member is in advance
of the radial axis of transmittal of said centrifugal force to said
second interengaging arcuate surfaces when said rotor is rotated
in the forward direction at impact speed.
3. A hammer assembly, as recited in claim 2 in which said first
interengaging arcuate surfaces on said base member and said hammer
member include connecting, interengaging concave and convex surfaces.
4. A hammer assembly, as recited in claim 3 in which said second
interengaging arcuate surfaces on said base member and said hammer
member include connecting, interengaging concave and convex surfaces.
5. A hammer assembly, as recited in claim 1 including first bolt
means extending through said base member and said rotor adjacent
said rotor periphery for attaching said base member to said rotor,
and second bolt means extending through said hammer member and said
base member for attaching said hammer member to said base member.
6. A hammer assembly, as recited in claim 1 in which said second
interengaging arcuate surfaces each include a first arcuate concave
portion and a second arcuate convex portion, said first concave
portion and said second convex portion being joined end to end.
7. A hammer assembly, as recited in claim 6 in which the first
arcuate concave portion of the second interengaging arcuate surface
of said hammer member engages the second arcuate convex portion
of the second interengaging arcuate surface of said base member,
and said second arcuate convex portion of the second interengaging
arcuate surface of said hammer member engages the first arcuate
concave portion of the second interengaging arcuate surface of said
base member.
8. A hammer member for use in replacement for rebuilding of a hammer
assembly for attachment to the rotor of a rotary material crusher
having a rotor for rotation about an axis of rotation, said hammer
assembly having a base member mounted in fixed position at one of
its ends on said rotor adjacent the periphery of the rotor so that
said base member does not pivot relative to said rotor, said base
member having at its other end a first arcuate surface extending
parallel to the axis of rotation of rotor and facing forwardly in
the direction of rotation of the rotor, and second arcuate surfaces
extending parallel to the axis of rotation of the rotor and facing
inwardly in a radial direction of that rotor, said hammer member
comprising a first impact surface which faces forwardly in the direction
of rotation of said rotor, and a second impact surface joined at
one of its edges to an outer end of said first impact surface which
faces outwardly of said rotor, a first arcuate surface extending
parallel to the axis of rotation of the rotor, which first surface
engages said first arcuate surface on said base member, and second
arcuate surfaces extending parallel to the axis of rotation of said
rotor, which second surfaces engage said second arcuate surfaces
on said base member.
9. A hammer member, as recited in claim 8 in which said second
arcuate surfaces on said hammer member include a first arcuate concave
portion which engages with a convex portion of the second arcuate
surface of the base member, and a second arcuate convex portion
which engages with a concave portion of the second arcuate surfaces
of the base member.
Description This invention relates to a hammer assembly for attachment to the
rotor of a rotary material crusher and, more particularly, to a
two piece hammer having a base member for attachment to the rotor
and a hammer member, which is replaceable and attached to the base
member.
In U.S. Pat. No. 3838826 and U.S. Application Ser. No. 023995
filed Mar. 9 1987 there are disclaimed two piece hammers for attachment
to the rotor of rotary material crushers. In such two piece hammers,
a base is attached, at one of its ends, to a rotor and an impact
member or hammer is fixed to the other end of the base member.
In the arrangement of U.S. Pat. No. 3838826 the outer end of
the base is provided with grooves extending tangential of the rotor
and the hammer members are provided with tongues which are fitted
into the grooves. The hammer members, with the tongues in the grooves,
are bolted to the base.
In the arrangement of application Ser. No. 023995 the outer end
of the base, at its side facing in the direction of rotor rotation,
is provided with a longitudinally extending tongue onto which a
groove at the back of the hammer member is positioned and the hammer
is then bolted onto the base.
In such rotary material crushers, the rotors are rotated at speeds
from 300 to 800 rpm and, depending upon the size and hardness of
the material fed to the crusher for crushing such hammers are subjected
to high impact forces when impacting the material being crushed
and high centrifugal forces when free of such material. Thus, the
impact force tends to force the hammer member inwardly and rearwardly
on the base member and the centrifugal force tends to swing the
hammer member outwardly. Such changes in the forces applied to the
hammer member induce bending forces between the hammer member and
base member, tend to loosen the hammer member on the base member,
cause damage to the surfaces where the hammer member and base member
are joined and cause failures on such surfaces due to fatigue of
the metal where the members are joined.
In the instant invention the foregoing problems of changes in forces
bending between the members, damage to the joining surfaces and
fatigue, and failure of the metal where the members join are overcome.
This is accomplished in the instant invention by providing selfseating
areas between the hammer member and the base member when the hammer
is subject to impact forces and to centrifugal forces which have
a maximum cross section in the area of impact and are self relieving
during changeover between impact and centrifugal loading.
In the instant invention, the head member and base member are each
provided with arcuate seats opposite the areas where impact forces
are applied to the head and base members and opposite the area where
centrifugal forces are applied to the members. These arcuate seats
extend across the members parallel to the axis of rotation of the
rotor and hammer assembly. The arcuate seats on the members interengage
and are self aligned when the impact and centrifugal forces are
applied, allowing the forces to be transmitted from the hammer member
to the base member during moments of material impact and crushing
without substantial transmission of force to centrifugal force arcuate
seat and substantial transmission of the centrifugal fences to the
impact arcuate seat during transmission of centrifugal forces.
The instant invention will be more fully understood from the following
description of a preferred embodiment of the invention taken with
the appended drawings, in which
FIG. 1 is a perspective view of an embodiment of the invention
fitted to one type of rotor;
FIG. 2 is an enlarged cross-section of the embodiment of FIG. 1
showing connections of the base member to the rotor and the hammer
member to the base member;
FIG. 3 is an enlarged end view of the hammer member and hammer
member end of the base member of the instant invention;
FIG. 4 is a perspective view, similar to FIG. 1 but showing attachment
of the base member to a rotor of another type;
FIG. 5 is an enlarged cross section of the embodiment of FIG. 4;
FIG. 6 is a perspective view, similar to FIGS. 1 and 4 but showing
attachment of the base member to a rotor of still another type;
FIG. 7 is an enlarged cross section of the embodiment of FIG. 6;
FIG. 8 is a perspective view, similar to FIGS. 1 4 and 6 but showing
attachment of the base member to a rotor of still a further type;
and
FIG. 9 is an enlarged cross section of the embodiment of FIG. 8.
Referring, first, to FIGS. 1-3 hammer member 2 is mounted on one
end of base member 4 by bolts 6 in recesses 8 of hammer member 2
extending through bolt holes 10 in hammer member 2 and bolt holes
12 in base member 4. Washers 14 and nuts 16 are applied to the threaded
ends of the bolts to mount hammer member 2 on the end of base member
4 the washers 14 and nuts 16 being mounted in recesses 18 in base
member 4.
The attachment of base member 4 to rotor 20 varies depending upon
the rotor manufacturer and the attachment system of such manufacture.
Thus, the attachments of base member 4 to rotor 20 in FIG. 2 and
to rotor 20' in FIGS. 4 and 5 rotor 20" in FIGS. 6 and 7 and
rotor 20'" in FIGS. 8 and 9 are not a part of the instant invention
but are merely illustration of base member to rotor attaching means.
In the attachment of FIGS. 1 and 2 groove 22 in rotor 20 is enlarged
at its inner end and the inner end 24 of base member 4 is offset
to fit the wall of groove 22. Base member 4 is fixed to rotor 20
in rotor groove 22 by bolts 26 and nuts 28 passing through holes
30 32 in base member 4 and rotor 20 respectively, the head of
bolts 26 and nuts 28 being recessed in recesses 34 36 of base member
4 and rotor 20 respectively. At its outer end hammer member 2
FIG. 3 is provided with teeth 40 42 and 44 which entered longitudinally
across the outer surface of hammer member 2 in conventional manner,
parallel to the axis of rotor 20 for impact with the material to
be crushed.
As best seen in FIG. 3 base member 4 has a concave arcuate surface
46 joined to a convex arcuate surface 48 which surfaces extend longitudinally
across the hammer member end of base 4 parallel to the axis of rotor
20 and are in contact with convex arcuate surface 54 and concave
arcuate surface 56 of hammer member 2. At the inner end of hammer
member 2 base member 4 has a second arcuate convex surface 50 joined
to a concave arcuate surface 52 in contact with concave arcuate
surface 58 and convex arcuate surface 60 respectively, of hammer
member 2. Like surfaces 46 48 54 56 the arcuate surfaces 50
52 of base member 4 and 5860 of hammer member 2 extend longitudinally
across base member 4 and hammer member 2 respectively.
As best shown in FIG. 3 the centrifugal force T acts radially
outward from the rotor center line along a line spaced forwardly
in the counter-clockwise direction of rotation of rotor 20 arrow
A, FIG. 3 of arcuate surfaces 50 52 58 and 60 such that the centrifugal
force acts in a tangential direction about the pivot point as the
arcuate surfaces 50 52 58 and 60. The movement created by the
centrifugal force acts in a clockwise direction about the center
of mass of hammer member 2 forcing the arcuate surfaces of hammer
member 2 and base member 4 into engagement and provide equilibrium
by the seating reaction at arcuate surfaces 46 48 54 56 of hammer
member 2 and base member 4 without over-stressing or shearing bolts
10.
Rock, or other material to be crushed, feed to the impact crusher
is impacted at the forward end of tooth 44 of hammer member 2 and
along the upper or outer end of hammer member 2 along teeth 40
42 and 44 generating impact forces R along the forward edge of
hammer member 2 FIG. 3. Such impact forces R are opposed by reaction
forces S along arcuate surfaces 46 48 54 56 without over-stressing
or shearing bolts 10. Thus, the impact forces are distributed over
a large seating area for superior metal utilization.
The arcuate surfaces 54 56 58 and 60 on head members 2', 2"
and 2'", FIGS. 4 and 5 6 and 7 and 8 and 9 respectively,
and arcuate surfaces 46 48 50 and 52 on base member 4', 4"
and 4'" are the same as in FIG. 3. FIGS. 4 and 5 6 and 7
and 8 and 9 show different attachment arrangements for attaching
the inner end of base members 4', 4" and 4'" to rotors
20', 20" and 20'" which, as already noted, are not a part
of the instant invention but are shown herein to demonstrate the
versatility of the present invention.
The terms and expressions which have been employed in the foregoing
description are used as terms of description and not of limitation,
and there is no intention, in the use of such terms and expressions,
of excluding any equivalents of the feature shown and described
or portions there, but it is recognized that various modifications
are possible within the scope of the invention claimed. |