Note: Descriptions are shown in the official language in which they were submitted.
CA 02956603 2017-01-26
Pick, in particular a round-shank pick
The invention relates to a pick, in particular to a
round-shank pick for use on a cutting roller, said pick
having a pick head and a pick shank for supporting the
pick in a pick holder, wherein the pick head of the
pick comprises at least one cutting region.
A pick of this type is disclosed in DE 37 01 905 Cl.
Said pick consists of a pick head and a pick shank
which is integrally formed thereon in the form of a
round shank. The pick head and pick shank are designed
so as to be rotationally symmetrical about a center
longitudinal axis of the pick. The transition of the
pick head to the pick shank is realized as a collar
which forms the largest external diameter of the pick
head. The pick head tapers conically toward a pick tip.
The pick tip is formed by a hard metal insert. The pick
is held by its pick shank in a corresponding receiving
means of a pick holder by means of a clamping sleeve.
In this case, the clamping sleeve engages in such a
manner in a groove which runs around the pick shank
that the pick is held in the axial direction, but is
able to rotate about its center longitudinal axis. This
provides the advantage of the pick wearing evenly on
all sides during its use.
Such picks are used, for example, on rotating cutting
rollers of so-called surface miners for removing rock
and earth in large-scale open cast mining. In this
case, the excavated material is crushed by the picks,
which are fastened on the cutting roller, and is
transported by means of the movement of the cutting
roller to an ejector where it is then removed, for
example by means of a conveyor system.
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A disadvantage of the described picks is their limited
transport capacity on account of their design, in
particular for softer excavated materials, such as, for
example, for oil sand.
It is, consequently, the object of the invention to
create a pick of the type mentioned in the introduction
with improved conveying function.
The object of the invention is achieved in that a
planar and/or hollowed ejection region is arranged in a
central region of the pick head connecting indirectly
or directly to the cutting region. The earth or rather
the rock is broken up and crushed by the cutting
region. The planar ejection region collects the
excavated material and transports it in the feed
direction of the pick and of the cutting roller. As a
result of the planar development of the ejection
region, finely crushed, plastically deformable or sandy
excavated material is also reliably collected and,
following the rotation of the cutting roller, is
transported in large quantities to an ejector.
A high cutting capacity with the pick, at the same
time, having a long service life is achieved as a
result of the cutting region comprising at least one
cutting element which is produced from a hard material,
in particular hard metal, and is attached on an end of
the pick remote from the pick shank on a front side of
the pick head which is aligned in the direction of a
feed device (V) and/or as a result of the ejection
region comprising at least one plate-shaped hard
material element, in particular produced from hard
metal, which connects indirectly or directly to the
cutting element. The cutting element and the plate-
shaped hard material element protect the region of the
pick head arranged behind them from abrasive wear. In
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this case, a particularly high level of resistance to
wear is achieved when the hard material element
connects directly to the cutting element such that
there is no gap between the elements which can be
attacked by the excavated material.
The removal, in particular of viscous or sandy
excavated material, can be improved as a result of a
deflection region, which extends toward the front side
of the pick, being arranged indirectly or directly on
the ejection region of the pick head, and as a result
of a shovel-shaped trough, which is aligned toward the
front side of the pick, being formed by the cutting
region, the ejection region and the deflection region.
Plastically deformable excavated material in the
cutting region, for example, is removed through the
trough and formed in the shape of a ball or roller over
the ejection region and the deflection region. The
material formed in this manner is transported further
through the ejection region and, in this case, is held
by the deflection region. Sandy excavated material is
held in the trough by the deflection region.
The abrasive wear of the pick head can be reduced
further as a result of the pick head comprising a
carrier portion which is arranged in the cutting region
and the ejection region, and as a result of the carrier
portion comprising lateral connection faces which are
arranged on both sides of the carrier portion in the
cutting region and/or the ejection region, the mutual
distance between said lateral connection faces,
proceeding from the front side toward a rear side of
the pick, being reduced. The width of the carrier
portion consequently tapers, proceeding from the front
side of the pick, which is directly exposed to the
excavated material, toward the rear side thereof. As a
result of the undercut formed in such a manner, the
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lateral connection faces are only exposed to a reduced
mechanical load by the excavated material. The heavily
loaded front side can be protected, as depicted, by
cutting elements and hard material elements such that
long service lives can be achieved for the picks. A
further advantage is produced as a result of a pick
formed in this manner being able to be moved in an
easier manner through the earth. The power to be
applied for moving the cutting roller is consequently
reduced, as a result of which energy is able to be
saved.
Corresponding to a preferred development variant of the
invention, it can be provided that the cutting element
is formed from a fastening piece which is aligned
toward the front side of the pick and from an
attachment which is aligned from the fastening piece
toward the rear side of the pick, that the cutting
element forms a cutting edge on the outermost end of
the pick head and that the cutting element, proceeding
from the cutting edge, realizes a diverting face toward
the fastening piece and a free face toward the
attachment. The cutting edge which is heavily loaded
mechanically and the regions which directly connect to
the cutting edge and are also heavily loaded
mechanically are consequently protected from increased
wear by a hard material. This leads to a clear increase
in the service life of the pick head.
Secure fastening of the cutting element on the carrier
portion can be achieved as a result of the fastening
piece realizing a contact face and the attachment
realizing a support portion and as a result of the
cutting element, by means of a substance-to-substance
bond between the contact face and contact region and/or
between the support portion and a support region of
said carrier portion, being held on the carrier
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portion. The substance-to-substance bond can be
produced, for example, by gluing or, in a preferred
manner, by soldering. In this case, a particularly
durable connection is produced when such a connection
is produced both between the contact face and the
contact region and between the support portion and the
support region. The risk of breakage for the cutting
element can be additionally reduced as a result of such
a two-sided fastening.
The service life of the pick head can be lengthened as
a result of the pick head being coated with an anti-
wear coating, in particular with an armor welding, in
the cutting region, in the ejection region and/or in
the deflection region. As a result, for example in the
cutting region, which is particularly mechanically
loaded, the lateral connection faces as well as a
connection face, which is arranged as an extension of
the free face of the cutting element, can be provided
with the anti-wear coating and consequently protected
against abrasive wear. In a corresponding manner, the
lateral connection faces in the ejection region of the
pick head can also be protected with an anti-wear
coating. As a result of said measures, the carrier
portion behind the cutting element and behind a hard
material element can be prevented from being washed out
and, as a result, the cutting element or the hard
material element from being detached from the carrier
portion. The deflection region, which connects to the
ejection region, can be provided with an anti-wear
coating toward the front side of the pick head and can
consequently be protected. As a result of said measure,
the trough of the pick head, which is aligned toward
the front side of the pick head and is directly exposed
to the excavated material, can be completely protected
from rapid abrasive wear. In an advantageous manner, in
this case, the cutting region which is loaded the
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heaviest and the ejection region which is also heavily
loaded are protected toward the front side by the
cutting element and the hard material element and the
less loaded deflection region is protected by the anti-
wear coating. As a result, a comparably long service
life can be achieved for all regions of the pick head
such that the pick head is not destroyed prematurely by
failure of a component.
In order to avoid the cutting element or the hard
material element being destroyed during the coating
process or the supporting faces, on which the cutting
element or the hard material element are mounted, being
deformed, it can be provided that the anti-wear coating
is applied to the cutting element and/or to regions of
the carrier portion carrying the hard material element
at least at a spacing of a minimum distance. In
particular, when applying the anti-wear coating as
armor welding, very high temperatures are reached in
the welding region. The minimum distance avoids the
cutting element, the hard material element or the
supporting faces thereof on the carrier portion being
exposed to high temperatures and being destroyed or
deformed as a result.
A high cutting capacity with at the same time fewer
torsion forces transmitted into the pick head can be
achieved as a result of the cutting edge of the cutting
element being arranged in the direction longitudinally
of a center longitudinal plane (M) of the pick, the
surface normal of which points in the direction of the
front side of the pick, in particular as a result of
the cutting edge being arranged along the center
longitudinal plane (M) of the pick.
Corresponding to a preferred realization of the
invention, it can be provided that the cutting element
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comprises on the front side a diverting face which is
formed in a belly-shaped manner, in particular
convexly, and/or that the diverting face comprises an
edge which is aligned toward the front side at a first
exterior angle and/or that the cutting edge comprises a
cutting tip at a second exterior angle and/or that the
free face comprises an edge at a third exterior angle
and/or that the exterior angles are arranged over a in
the direction longitudinally of a second center
longitudinal plane of the pick which extends from the
front side to the rear side. As a result of the belly-
shaped diverting face, the cutting element is
reinforced in a region which is subject to particularly
serious wear in such a manner that the service life of
the cutting element is able to be significantly
increased. The same also applies to a diverting face
which comprises a forwardly pronounced edge along the
center longitudinal plane. As a result of the belly-
shaped form, the excavated material is transported in a
reinforced manner to the ejection region. As a result
of the edge, the movement of the excavated material
additionally obtains a lateral component such that it
is present in a more evenly distributed manner in the
ejection region. As a result of the realization of a
cutting tip, =the pick penetrates in an easier manner
into harder earth and rock. In this case, non-removed
excavated material can be pressed to the side by a free
face which is also provided with an outside edge. A
cutting element with an edge which is arranged along
the center longitudinal plane, which extends from the
front to the rear side of the pick, shows better
cutting and excavating results with harder material,
whilst a convexly formed cutting element is better
suited for soft and plastically deformable earth. Picks
with cutting elements with an outside edge can
consequently be used, for example, in winter when the
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earth is frozen, whilst picks with belly-shaped cutting
edges are provided in the summer.
In contrast to a pick with a rotationally symmetrical,
tapering pick head, the pick according to the invention
comprises a defined front and rear side. So that the
front side, provided with the cutting element, can
remain aligned in the feed direction in operation, it
can be provided that the pick shank is realized as a
round shank and that the pick shank comprises at least
one positive locking element which is suitable to
interact with a positive locking counter element of the
pick holder or that the pick holder has assignable
thereto a blocking piece as a positive locking counter
element which is securable on the pick holder and that
the pick is securable in an anti-rotational manner on
the positive locking counter element by way of the
positive locking element. The pick is thus held in the
pick holder in an anti-rotational manner in spite of
its round pick shank. In an advantageous manner, the
pick can be held in the same pick holders as known
round-shank picks which have a symmetrical pick head
and in operation are rotated about their center
longitudinal axis. Consequently, a cutting roller can
be provided with known rotating picks or with blocked
picks according to the invention in dependence on the
material to be removed.
In order to block the pick in its axial position and to
protect the pick holder from increased wear, it can be
provided that the pick head comprises a support body on
the side of the pick shank and that the support body is
closed off by means of a support face which protrudes
radially above the pick shank. The support face thus
lies on an end face of the pick holder which runs
around a pick receiving means. As a result, a large-
area supporting face is produced between the pick head
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and the pick holder such that large forces introduced
in the axial direction onto the pick head can also be
transmitted to the pick holder without deforming the
supporting faces. As a result of the protrusion of the
support body, the excavated material is steered past
the pick holder such that the abrasive attack of the
excavated material on the pick holder is able to be
kept small.
The material flow of the excavated material is
influenced in a decisive manner by the shaping of the
trough of the pick head. The material crushed by the
cutting element can be removed efficiently as a result
of a deflection face, which runs from the ejection
region to the front side of the pick head, being formed
by means of the deflection region and as a result of
the deflection face, proceeding from a middle region of
the pick head toward the front side thereof, falling
away in the direction of the pick shank. The support
body which lies under the deflection face is covered
and protected by the protection face. There is a high
level of mechanical protection in this case in
particular when the deflection face is provided with an
anti-wear coating.
The invention is explained in more detail below by way
of an exemplary embodiment shown in the drawings, in
which:
fig. 1 shows a side view of a pick for removing
comparatively soft material,
fig. 2 shows a side view of the upper end of a pick
head of the pick shown in figure 1 with a
cutting element,
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fig. 3 shows a perspective rear view of the pick from
figure 1,
fig. 4 shows a side view of a second pick for removing
comparatively harder material,
fig. 5 shows a perspective rear view of the second pick
from figure 4,
fig. 6 shows a further perspective rear view of the
pick from figure 1,
fig. 7 shows a section through a pick holder
corresponding to a cutting surface shown in
figures 1 and 4 and
fig. 8 shows a detail of the pick shown in figures 1
and 4 in the region of a blocking piece.
Figure 1 shows a side view of a pick 10 for removing
comparatively soft material, in particular oil sand or
other plastically deformable or sandy earth.
The pick 10 comprises a pick head 20 and a pick shank
40 which is integrally molded thereon, the pick shank
40 being present essentially in the form of a
cylindrical round shank 42. The pick head 20 comprises
a support body 27 which faces the pick shank 40 and
merges into a carrier portion 23. The carrier portion
23 forms a shovel-shaped trough 20.6 which is aligned
toward a front side 20.1 of the pick 10 and of the pick
head 20. The pick head 20 is divided along the shovel-
shaped trough 20.6 into three regions marked by double
arrows, namely into a front cutting region 20.3, a
center ejection region 20.4 and a rear deflection
region 20.5. In the cutting region 20.3, two cutting
elements 30, which are arranged side by side, are
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fastened on the carrier portion 23 toward the front
side 20.1 of the pick head 20, as can be seen more
clearly in figure 3. In the ejection region 20.4, two
plate-shaped hard material elements 28, which are
arranged side by side, cover the carrier portion 23
which is located behind them. A deflection face 24.5,
which is provided with an anti-wear coating 29 and
extends as a result of a corresponding, lightly curved
shape from the plane of the ejection region 20.4 formed
by the hard material elements 28 to the front side 20.1
of the pick head 20, is arranged in the deflection
region 20.5. The deflection face 24.5, in this case, is
aligned in such a manner that it falls away from the
transition to the ejection region 20.4 toward the front
closure of the pick head 20.
In the rear-sided connection to the cutting elements 30
and the hard material elements 28, the carrier portion
23 realizes upper and lower lateral connection faces
25.1, 25.2. As can be seen in figure 1 and figure 3,
the lateral connection faces 25.1, 25.2 are provided
with an anti-wear coating 29. The lateral connection
faces 25.1, 25.2 connect laterally to the cutting
elements 30 and hard material elements 28 in their
front-sided regions. The mutual distance between the
lateral connection faces 25.1, 25.2, which are located
oppositely on the two sides of the pick head 20,
reduces toward a rear side 20.2 of the pick 10 and of
the pick head 20.
As shown in figure 1 and in an enlarged manner in
figure 2, the cutting element 30 is formed in a
substantially L-shaped manner from a fastening piece 36
and an attachment 32, which is molded thereon at an
angle to the rear side 20.2 of the pick head 20. Toward
the front side 20.1, the fastening piece 36 can
comprise a diverting face 37 which is formed in a
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belly-shaped manner and merges into a cutting edge 31
at the outermost end of the cutting element 30 and
consequently of the pick head 20. Proceeding from the
cutting edge 31, a downwardly sloping free face 33,
which is aligned in an opposite manner to a feed
direction V of the pick 10, is formed by the attachment
32. Located opposite the diverting face 37, the
fastening piece 36 comprises a contact face 35 which is
at an angle to a support portion 34 which is arranged
opposite the free face 33. The contact face 35 and the
support portion 34 are placed onto a contact region
24.2 and a support region 24.1 of the carrier portion
23 and are connected thereto by means of a substance-
to-substance bond produced, for example, by soldering.
As an alternative to this, the substance-to-substance
bond can also be produced by gluing. As an extension to
the free face 33, the carrier portion 23 comprises a
connection face 26.1 which is also provided with an
anti-wear coating 29 and merges into a rounding region
26.2 of the carrier portion 23. The inclined alignment
of the connection face 26.1 merges via the rounding
region 26.2 into the alignment of the outside face of
the support body 27, which extends along the direction
of a center longitudinal plane M.
The cube-shaped hard material elements 28 are fastened
on the front side 20.1 of the pick head 20 directly
connected to the cutting elements 30. To this end, the
hard material elements 28 are connected by way of their
rear side to a fastening plane 24.4 of the carrier
portion 23 in a substance-to-substance bonding manner
as a result of, in the present exemplary embodiment,
soldering, as an alternative to this as a result of
gluing. For the precise positioning of the hard
material element 28, a step-shaped positioning edge
24.3, against which the hard material element 28 abuts
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by way of its upper end face, is provided between the
contact region 24.2 and the fastening plane 24.4.
The anti-wear coating 29 of the lateral connection
faces 25.1, 25.2 of the connection face 26.1 and of the
deflection face 24.5 is spaced from the cutting element
30 or rather from the hard material element 28 by a
minimum distance.
The closure of the pick head 20, located opposite the
cutting element 30, is formed by the cylindrical
support body 27, which merges integrally into the pick
shank 40. In this case, a conical centering portion 41,
which runs around the cylindrical round shank 42, is
provided in the transition from an end-side support
face 27.1 of the support body 27, which protrudes
radially beyond the pick shank 40, to the round shank
42. A conical tapering region 43, on which a positive
locking element is integrally molded in the form of a
blocking pin 44, connects to the round shank 42. The
blocking pin 44 comprises pin faces 44.1 on the two
lateral faces and on the rear side and a pin rounding
44.2 to the front side 20.1. The pick shank 40 is
closed off at the end by a disk-shaped end piece 46
which is separated from the blocking pin 44 by a groove
45.
As shown further by figure 1, the pick 10 is held in a
pick holder 50 over its pick shank 40. The pick holder
50 is shown in a sectional representation for the
purposes of better presentation.
The pick holder 50 comprises a holding region 54 toward
the pick head 20 and a base part 56 located opposite.
It has a cylindrical basic form which is tapered as a
result of an inclination 53 in a region which faces the
pick head 20. The inclination 53 merges via a rounded
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edge into an end face 51, which is aligned transversely
with respect to the center longitudinal axis of the
pick 10 and against which the support face 27.1 of the
pick head 20 abuts. Toward the pick shank 40, the end
face 51 comprises a centering receiving means 52 in the
form of a bevel which is adapted to the centering
portion 41 of the pick 10. The centering portion 41
forms the closure of a pick receiving means 55 which is
arranged in the holding region 54 of the pick holder
50. The pick receiving means 55 is realized as a
cylindrical bore following the contour of the round
shank 42 of the pick shank 40.
As can be seen from figure 1 and from the perspective
rear view from figure 3, the base part 56 of the pick
holder 50, by means of a front wall 56.5 which is
aligned toward the front side 20.1 and a rear-sided
mounting opening 56.3, forms a part-surrounded cavity
57, which is open through the mounting opening 56.3 and
toward the end side of the pick holder 50. The mounting
opening 56.3, in this case, is delimited by closure
faces 56.4 of the approximately semicircular front wall
56.5, the closure faces 56.4, proceeding from the
holding region 54 of the pick holder 50, being arranged
extending toward the lower end of the base part 56 at
an angle toward the front side 20.1 of the pick holder
50.
The cavity 57 itself is delimited toward the front side
20.1 by the front wall 56.5 by way of its approximately
semicircular front wall face 56.1 which merges
laterally into two side wall faces 56.2, which open
slightly toward the mounting opening 56.3 and extend in
a straight line, as is shown more clearly in a
sectional representation in figure 7 which extends
along the cutting line marked by reference VII.
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As is further shown in figure 1, the blocking pin 44 of
the pick shank 40 is secured in a blocking piece 60
which is shown in a sectional representation. The
blocking piece 60 is held by a clamping element 70,
which engages in the groove 45 of the pick shank 40, in
the axial direction thereof. The blocking piece 60
forms a positive locking connection in relation to both
the pick holder 50 and in relation to the blocking pin
44, said positive locking connection preventing a
rotation of the pick 10 about its center longitudinal
axis. The blocking pin 44 is held for this purpose in a
breakthrough 64 of the blocking piece 60.
The pick holder 50 is not shown with its front side
20.1 welded on a cutting roller. For mounting onto the
pick holder 50, the pick 10 is inserted with its pick
shank 40 into the pick receiving means 55 thereof, the
blocking piece 60 is fitted onto the blocking pin 44
and the clamping element 70 is clamped into the groove
45. The alignment of the blocking piece 60 is
predefined by its outside contour and the contour of
the cavity 57. The alignment of the pick 10 is also
determined by the shape of the blocking pin 44 and of
the breakthrough 64 of the blocking piece 60 such that
its front side 20.1 points in the feed direction V of
the cutting roller and consequently of the pick 10. In
the axial direction, the pick 10 is determined by the
contact of the pick head 20 with its support face 27.1
on the end face 51 of the pick holder 50 as well as by
the clamping element 70 which engages in the groove 45.
The pick 10, which is realized as a round-shank pick,
is consequently held in a non-rotatable manner in the
pick holder 50.
In operation, the pick 10 is driven through the earth
to be removed in the feed direction V by the rotation
of the cutting roller. In this case, first of all the
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front cutting edge 31 engages in the earth and crushes
it. As a result of the cutting edge 31, which is wide
compared to a pick tip of a known round-shank pick, the
earth is removed and collected along a comparatively
wide line. The excavated material, which is removed in
this manner, is directed into the ejection region 20.4
of the pick head 20 as a result of the convex design of
the deflecting face 37 of the cutting element 30.
There, the excavated material is collected by the hard
material elements 28 and entrained in a manner
corresponding to the rotation of the cutting roller. In
particular, where the excavated material is not
consistent, such as, for example, rock or non-adherent
sand, the deflection face 24.5 prevents the excavated
material from flowing out of the trough 20.6. In the
case of plastically deformable excavated material, it
is guided as a result of the shovel shape of the trough
20.6 from the cutting region 20.3 via the ejection
region 20.4 to the deflection region 20.5 and, at the
same time, is formed into ball-like or roller-like
clumps. The material, which is formed in this manner,
is transported in the trough 20.6 for example to an
ejector, from where it is then removed, for example by
a conveyor system (not shown).
The top surface of the pick head 10, which forms the
trough 20.6 in the cutting region 20.3 and in the
ejection region 20.4 and is formed, in the present
exemplary embodiment, by the cutting elements 30 and
the hard material elements 28, extends substantially
along the center longitudinal plane M of the pick 10.
In this case, the surface normal of the center
longitudinal plane M points in the direction of the
front side 20.1 of the pick 10. The pick head 20
comprises its largest diameter in the region of the
center longitudinal plane M. Consequently, the cutting
region 20.3 and the ejection region 20.4 can be
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realized in a very wide manner transversely with
respect to the feed direction V, as a result of which a
high conveying capacity is produced for the excavated
material. The pick 10 is consequently particularly
suitable for excavating comparatively soft material,
for example oil sand.
The cutting region 20.3 is under the greatest
mechanical load when the pick 10 is operating.
Consequently, in said region the pick 10 is protected
toward its front side 20.1 by the fastening piece 36
with the diverting face 37 of the cutting element 30
which is produced from a hard material, in the present
case from hard metal. As a result of the belly-shaped
design of the fastening piece 36, the greatest material
strength of the cutting element 30 lies in the region
of the greatest abrasion, this then being reduced as
the distance to the cutting edge 30 increases and
consequently the mechanical load diminishes. As a
result of said optimized use of material, the
manufacturing costs of the cutting element 30, which
are essentially influenced by the cost of the
materials, can be reduced. The forces transmitted into
the cutting elements 30 and consequently the breaking
risk thereof are able to be reduced as a result of
using two adjacent cutting elements 30 compared to one
wider, single cutting element 30.
The attachment of the cutting element 30 can be guided
past the remaining earth following the cutting edge 31
via the free face 33 which is aligned in the feed
direction V. The free face 33 merges without a large
step into the identically aligned connection face 26.1
such that, here too, no attack points are produced for
the excavated material sliding past. The cutting
element 30 is connected fixedly to the carrier portion
23 as a result of its solder connection to the contact
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face 35 and the support portion 34, the force being
introduced onto the cutting element 30 substantially in
a direction opposite to the feed direction V and
consequently acting as a pressing force onto the
boundary face between the cutting element 30 and the
carrier portion 23. High tensile forces which act on
the boundary face can be avoided in this way such that
the cutting element 30 is held reliably on the carrier
portion 23. The connection face 26.1 as well as the
upper lateral connection faces 25.1, which connect to
the cutting element 30 on the oppositely situated sides
of the pick head 10, are provided with the anti-wear
coating 29 which is realized as armor welding.
Consequently, the cutting region 20.3 is fully wear-
protected except for a minimum distance provided
between the anti-wear coating 29 and the cutting
element 30. The anti-wear coating 29 prevents, in
particular, the region of the carrier portion 23
connecting to the cutting elements 30 from being washed
out and, as a result, the cutting elements 30 coming
loose from the carrier portion 23.
The ejection region 20.4 is protected by the hard
material elements 28 toward the front side 20.1. As the
ejection region 20.4 is under less of a load than the
cutting region 20.3, the material strength of the hard
material elements 28 is reduced compared to the
material strength of the cutting elements 30. The hard
material elements 28 are connected to the carrier
portion 23 as a result of a substance-to-substance
connection which is produced by soldering. The lower
lateral connection faces 25.2, which connect to the
hard material elements 28 and the deflection face 24.5,
are also protected from increased abrasion with armor
welding as an anti-wear coating 29 such that the region
behind the hard material elements 28 is not washed out
either. On the rear side, the carrier portion 23 is set
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back in the ejection region 20.4 and in the deflection
region 20.5 from the remaining excavated material by
the rounding region 26.2 such that, here, there is only
a comparatively small abrasive load on the pick head 20
when the pick 10 slides past the earth. In order to
keep the manufacturing costs low, no anti-wear coating
29 is provided in said region.
As the mutual distance between the oppositely situated
upper lateral connection faces 25.1 and the oppositely
situated lower lateral connection faces 25.2,
proceeding from the cutting elements 30 or rather from
the hard material elements 28, is reduced toward the
rear side 20.2 of the pick head 20, an undercut is
formed. The lateral connection faces 25.1, 25.2
consequently do not form an attack point for the
excavated material. As a result, on the one hand the
wear on the lateral connection faces 25.1, 25.2 is
reduced, on the other hand the pick 10 can be pulled
through the earth to be excavated in an easier manner.
As a result, the output necessary to drive the cutting
roller is reduced, as a result of which energy is
saved.
The deflection region 20.5 is subjected to the least
abrasion compared to the cutting region 20.3 and the
ejection region 20.4. Consequently, the anti-wear
coating 29 applied to the deflection face 24.5 provides
sufficient protection of the deflection region 20.5. It
is thus possible to dispense with expensive hard
material elements in the deflection region 20.5. The
anti-wear coating is consequently adapted in such a
manner to the different mechanical loads of the cutting
region 20.3, of the ejection region 20.4 and of the
deflection region 20.5 that substantially identical
service lives are produced for all the regions. This
avoids the pick 10 failing prematurely on account of
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design-related premature wear in one region. At the
same time, the use of the material, in particular for
the cost-intensive hard materials and anti-wear
coatings 29, is optimized.
The anti-wear coating 29 is applied to the cutting
elements 30 and the hard material elements 28 only up
to a minimum distance. This avoids the cutting elements
30 or the hard material elements 28 being damaged or
destroyed by the high temperatures which occur with the
coating. In addition, thermally-related deformation of
the contact regions for the cutting elements 30 and the
hard material elements 28 is avoided.
The substantially cylindrically realized support body
27 covers the upper region of the pick holder 50 and
consequently protects it from premature wear.
Consequently, this results in a service life for the
pick holder 50 being significantly longer than that of
the easily exchangeable pick 10 itself. A large-area
supporting face of the pick head 20 is formed on the
end face 51 of the pick holder 50 by the support face
27.1 of the support body 27 which is arranged about the
pick shank 40 such that deformation as a result of
forces introduced via the pick head 20 are able to be
avoided in said region.
The pick receiving means 55 comprises a diameter which
is larger by a predefined clearance compared to the
round shank 42 of the pick 10, whereby the pick shank
is able to be introduced easily into the pick
receiving means 55 during mounting and driven out again
during removal. A precise alignment of the pick 10 and
of the pick shank 40 in relation to the pick receiving
35 means 55 is obtained as a result of the centering
portion 41 interacting with the centering support 52.
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In the holding region 54, the pick holder 50 is
realized in a thick-walled manner about the pick
receiving means 55, which is realized as a central
bore, in order to be able to absorb, in a reliable
manner, the cross forces which are transmitted by the
pick holder 40. To this end, the diameter of the pick
holder 50, proceeding from the end face 51 which faces
the pick head 10, is widened by the inclination 53.
Excavated material sliding past is directed past the
pick holder 50 by the inclination 53 without any
protruding edges such that the abrasion forces are able
to be kept as low as possible in said widened region of
the pick holder 50.
By way of its front wall 56.5, the base part 56 of the
pick holder 50 surrounds the formed cavity 57 toward
the front side 20.1. In this case, the outside contour
of the front wall 56.5 is adapted to the outside
contour of the connecting holding region 54 such that
the pick holder 50 is able to be placed into a
corresponding receiving means on the cutting roller and
welded there.
During mounting, the blocking piece 60 can be slid
through the mounting opening 56.3 onto the blocking pin
44 and fixed, together with the pick 10, by way of the
clamping elements 70. Rotation of the pick 10 about its
center longitudinal axis is inhibited as a result of a
positive locking connection between the blocking piece
60 and the blocking pin 44. In a corresponding manner,
rotation of the blocking piece 60 about the center
longitudinal axis of the pick 10 is blocked by a second
positive locking connection between the blocking piece
60 and the base part 56. In this case, the positive
locking connections between the blocking piece 60 and
the blocking pin 44 of the pick 10 as well as between
the blocking piece 60 and the base part 56 are realized
CA 0296133 2017-016
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in such a manner that the blocking piece 60 can only be
introduced into the cavity 57 in a radial alignment and
the pick 10 can only be introduced into the
breakthrough 64 of the blocking piece 60 in one
direction of rotation. The shovel-shaped trough 20.6 of
the pick head 10 is consequently always aligned toward
the front side 20.1 and consequently toward the feed
direction V.
To remove the pick 10, the clamping element 70 is
pulled out of the groove 45 and the blocking piece 60
removed. The pick 10 can now be driven out, where
applicable with the aid of a driving-out tool, from the
side of the opening in the base part 56 which is
situated opposite the holding region 54.
Figure 4 shows a side view of a second pick 11 for
removing comparatively harder material. Identical
components, in this case, are designated identically in
a manner corresponding to figures 1 to 3.
In contrast to the pick 10 shown in figures 1 to 3, the
second pick 11 shown in figure 4 comprises simply a
cutting region 20.3 and an ejection region 20.4. In the
cutting region 20.3, the carrier portion 23 is covered
toward the front side 20.1 of the pick head 20 by one
single, substantially L-shaped cutting element 30. As
an extension of the fastening piece 36 of the cutting
element 30, a cube-shaped hard material element 28 is
mounted on the front side 20.1 of the carrier portion
23 in the connecting ejection region 20.4. Two or more
hard material elements 28, which are arranged side by
side, can also be provided as an alternative to this.
As shown in figure 4 and in particular in a perspective
rear view of the second pick 11 in figure 5, the
diverting face 37 is realized in a roof-shaped manner,
CA 0296133 2017-016
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an edge of the diverting face 37, which is formed in a
manner corresponding to a roof ridge, being aligned
along a center longitudinal plane of the second pick 11
which extends from the front side 20.1 to the rear side
20.2. The cutting element 30 is mounted on the carrier
portion 23 aligned in such a manner at an angle to the
center longitudinal plane of the second pick 11 that
the edge points approximately in the feed direction V
of the second pick 11. The free face 33, which is
formed by the attachment 32, is also realized in a
roof-shaped manner, the face plane being aligned here
along the feed direction V. An edge of the free face
33, which extends in a manner corresponding to a roof
ridge, is also arranged along the center longitudinal
plane of the second pick 11 which extends from the
front side 20.1 to the rear side 20.2. In the
transition region from the diverting face 37 to the
free face 33, the cutting edge 31 is formed as a result
with a cutting tip 38 which lies on the center
longitudinal plane. In an alternative embodiment, the
cutting region 20.3 can also bear two cutting elements
which are designed in a mirror-symmetrical manner
and abut against one another along the described edges
which extend on the center longitudinal plane.
Following the free face 33 of the cutting element 30,
the carrier portion 23 comprises a flat connection face
26.1 which is aligned in the same direction as the
attachment 32 of the cutting element 30. The connection
face 26.1 is provided in part with an anti-wear coating
29. At the rear end of the pick head 20, the connection
face 26.1 bends into a rear-sided surface area of the
pick head 20 which extends equidistantly to the center
longitudinal axis of the second pick 11. Said rear-
sided surface area merges seamlessly into the
cylindrical region of the support body 27.
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The hard material element 28 is mounted in a manner
slightly inclined toward to the front side 20.1 of the
ejection region 20.4 in relation to the center
longitudinal plane M. The positioning edge 24.3 for
positioning the hard material element 28 is formed by a
step on the lower end of the ejection region 28, from
which the pick head 20 assumes a cylindrical outside
contour toward the front side 20.1. The hard material
element 28 is placed onto the position edge 24.3 by way
of an end face.
The pick head 20 of the second pick 11 does not realize
a trough 20.6, as is the case with the pick 10 shown in
figures 1 to 3. The front surface area of the carrier
portion 23 of the second pick 11, which is formed by
the diverting face 37 of the cutting element 30 and the
hard material element 28, is guided, proceeding from
the cutting edge 31 arranged in the region of the
center longitudinal plane M, in the direction of the
front side 20.1 of the pick head 20. Consequently, the
carrier portion 23 of the second pick 11 comprises a
significantly greater material strength than the
carrier portion 23 of the first pick 10 shown in
figures 1 to 3. The support body 27, the pick shank 40,
the blocking piece 60, the clamping element 70 and the
pick holder 50 are identically designed with identical
functionality for both picks 10, 11.
The second pick 11 is particularly suited for the
removal of hard, non-plastically deformable or non-
sandy material. In addition, the second pick 11 can be
used, in a preferred manner, in winter when the earth
is frozen, for example in the case of frozen oil sand,
whilst the pick 10 shown in figures 1 to 3 is used when
the ground has thawed.
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The second pick 11 is also able to remove rock or
frozen material as a result of the realized cutting tip
38. As a result of the reinforced carrier region 23,
higher forces can be transmitted to the excavated
material without the pick head 20 being damaged such
that even hard material is able to be removed. As a
result of the roof-shaped diverting face 37 of the
cutting element 30, the solid excavated material is
distributed laterally and then collected and removed by
the hard material element 28 in the ejection region
20.4. The second pick 11 consequently provides a high
cutting capacity and a high transport capacity for
hard, brittle material.
Figure 6 shows a further perspective rear view of the
pick 10 from figure 1. The representation enables the
view through the mounting opening 56.3 into the cavity
57 of the pick 10.
As shown in figure 6, the blocking piece 60 is placed
onto the pick shank 40, only the end piece 46 of which
can be seen, and is held by the clamping element 70
which is inserted into the groove 45 of the pick shank
40.
The blocking piece 60 shows an approximately U-shaped
outside contour, by way of which it abuts against the
correspondingly formed front wall 56.5 with its front
wall face 56.1 and its side wall faces 56.2. As a
result of said U-shaped form and the abutment against
the side wall faces 56.2, the blocking piece 60 is
blocked against rotation about the center longitudinal
axis of the pick 10. The blocking piece 60 comprises a
basic body 61, on which a web 63 is integrally molded.
The web 63 surrounds a clamping receiving means 62
except for a region which is aligned in the direction
of the mounting opening 56.3 of the pick holder 60. The
CA 0296133 2017-016
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clamping element 70 is arranged in the clamping
receiving means 62 and clamped at the groove 45.
The clamping element 70 is realized in a plate-like
manner with a rectangular basic form. A clamping region
73, which is comprised by two clamping jaws 74 and in
which the pick shank 40 with its groove 45 is clamped,
is provided proceeding from a front end face. A
widening clamping slot 72, which ends at a bracket 71
which connects the clamping jaws 74, is provided
centrally of the clamping element 70 proceeding from
the clamping region 73. The clamping element 70 is
preferably produced from a resilient material, in
particular from a spring steel.
For mounting, the pick 10 is introduced with its pick
shank 40 into the pick receiving means 55 of the pick
holder 50. The blocking piece 60 is then slid through
the mounting opening 56.3 onto the pick shank 40 and
fixed with the clamping element 70. To this end, the
clamping element 70 is pressed with its clamping region
73 onto the groove 45, the two clamping jaws 74 being
pressed apart along the clamping slot 72 in order then
to be placed fixedly in the groove 45 about the pick
shank 40.
Figure 7 shows a section through the pick holder 50
corresponding to a cutting face VII shown in figures 1
and 4.
The semicircular front wall face 56.1 with the side
wall faces 56.2, which connect thereto on both sides
and extend in a straight line, is formed by the front
wall 56.5 of the base part 56. The outside contour of
the approximately U-shaped blocking piece 60 is adapted
to the development of the front wall face 56.1 and of
the side wall faces 56.2 such that it abuts against the
CA 02956603 2017-01-26
- 27 -
front wall face 56.1 by way of a rounding 65.2, which
is aligned toward the front side 20.1, and against the
two side wall faces 56.2 of the front wall 56.5 by way
of two blocking faces 65.1 which connect laterally to
the rounding 65.2.
The contour of the breakthrough 64 of the blocking
piece 60 is adapted to the outside contour of the
blocking pin 44. To this end, the breakthrough 64
comprises, in each case to the rear side 20.2 and
laterally, a breakthrough face 64.1 which, in each
case, abuts against a pin face 44.1 of the blocking pin
44. Toward the front side 20.1, the breakthrough 64
comprises a convex breakthrough rounding 64.2 which
abuts against a pin rounding 44.2 of the blocking pin
44.
As a result of the stepped cutting sequence shown in
figures 1 and 4, the end region of the clamping
receiving means 62 can be seen with the bracket 71 of
the clamping element 70 toward the mounting opening
56.3.
The alignment of the blocking piece 60 is fixedly
predefined as a result of adapting the outside contour
of the blocking piece 60 to the development of the
front wall face 56.1 and of the side wall faces 56.2.
In this case, a rotation of the blocking piece 60 about
the center longitudinal axis of the pick 10, 11 is
blocked by the blocking faces 65.1 which abut against
the side wall faces 56.2.
The blocking pin 44 of the pick shank 40 can also only
be introduced in one alignment into the breakthrough 64
of the blocking piece 60 on account of the pin rounding
44.2 and of breakthrough rounding 64.2 which
corresponds thereto. The alignment of the pick 10, 11
CA 0296133 2017-016
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and consequently of the pick head 20 is determined
thereby. A rotation of the pick 10, 11 about its pick
longitudinal axis is blocked by the pin faces 44.1
which abut against the breakthrough faces 64.1.
Figure 8 shows a detail of the picks 10, 11 shown in
figures 1 and 4 in the region of the blocking piece 60.
The blocking piece 60 is formed from the basic body 61,
which includes the blocking pin 44 and realizes a stop
face 61.1 in the direction toward the holding region 54
of the pick holder 50. The stop face 61.1 is arranged
at a small distance in relation to a corresponding
counter face 54.1 of the holding region 54, which is
arranged radially about the pick receiving means 55. A
guide web 66, the inside contour of which follows the
blocking pin 44 and the outside contour of which
follows the pick receiving means 55 of the pick holder
50, is integrally molded on the basic body 61 directly
about the breakthrough 64. The guide web 66 is
introduced into the end region of the pick receiving
means 55, as a result of which the blocking piece 60 is
radially secured. In order to avoid tilting during the
mounting procedure, the guide web 66 comprises a bevel
66.1 all around. The blocking pin 44 is introduced into
the breakthrough 64 of the blocking piece 60, by way of
which the blocking pin realizes a positive locking
connection which prevents the pick 10, 11 from
rotating.
Toward the outer periphery, the basic body 61 comprises
a circumferential beveling 61.2 which lies toward the
front wall 56.5 in relation to a projection 56.6 of the
base part 56 of the pick holder 50.
The web 63 is integrally molded on the basic body 61 on
the side of the blocking piece 60 located opposite the
holding region 54. The web 63 surrounds the clamping
CA 0296133 2017-016
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receiving means 62 except for a region which is aligned
in the direction of the mounting opening 56.3 of the
pick holder 60. The clamping element 70 is arranged in
the clamping receiving means 62 and is clamped at the
groove 45 which is realized between the blocking pin 44
and the end piece 46.
The blocking piece 60 consequently blocks a rotational
movement of the pick 10, 11 and, interacting with the
clamping element 70, a movement of the pick 10, 11 in
the axial direction, except for a small clearance. The
small clearance is produced from the small distance
between the stop face 61.1 and the counter face 54.1.
The clearance facilitates the mounting or rather the
removal of the pick 10, 11 and compensates for
tolerances. As a result of the stop face 61.1, tensile
forces, which act axially on the pick 10, 11, are able
to be transmitted to the pick holder 50 by means of the
counter face 54.1. The clamping element 70 enables
quick mounting and removal of the pick 10, 11. As the
clamping element 70 is received in the clamping
receiving means 62 of the blocking piece 60, it is
protected from damage by penetrating excavated material
to the greatest possible extent.
The pick holder 50 is able to receive both picks 10, 11
that are blocked from rotating and also such round-
shank picks where rotation is desired. In this case, in
the event of the latter, for example the blocking pin
44, the blocking piece 60 and the clamping element 70
are omitted, the known holding elements for blocking a
movement of the round-shank pick in the axial direction
having to be provided in their place. The cutting
roller can thus be provided with different picks 10, 11
depending on the area of application.
