Note: Descriptions are shown in the official language in which they were submitted.
CA 02505415 2002-05-17
21182-331E
BACKGROUND OF THE INVENTION
This application is a divisional of Canadian
application Serial No. 2,386,693, filed May 17, 2002.
1. Field of the Invention
The invention relates to a method, an arrangement,
and a device for automatically changing knife units of a
knife ring of a knife ring slicing device, wherein a knife
changing magazine provided with resharpened knife units is
moved into a defined knife changing position relative to the
knife ring in which at least some of the knife receptacles
in the knife changing magazine are axially aligned with at
least some of the knife receptacles in the knife ring. In
particular, the invention relates also to a device for
communicating material especially in the form of a knife
ring slicing device, comprising a tool ring, which has
uniformly distributed about its circumference tool
receptacle for the comminution tools, and comprising a unit
for pushing out the comminution tools, arranged on the
periphery of the device, wherein the unit for pushing the
comminution tools comprises several pushing elements which
are axially aligned with the comminution tools to be pushed
out and are advanced and retracted axially into and out of
the tool receiving units of the tool ring by means of an
advancing drive. The invention furthermore relates to a
knife changing magazine for automatically changing the knife
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units of a knife ring, wherein the knife changing magazine
has areas with receptacles for the knife units of a knife
group to be exchanged at once.
2. Descrivtion.of the Related Art
For producing wood strands as the starting material for
manufacturing board-shaped structural components, slicing
machines are known whose comminution tools are arranged in a
stationary or rotating knife ring and operate relative to a
stationary or rotating abutment. The strands produced in
this way pass in the radial direction through the knife ring.
The quality of the final product is greatly affected by the
quality of the strands used as the starting material. The
strands should have cut surfaces as smooth as possible and
also identical dimensions. In order to ensure a constantly
high quality of the strands, it must be ensured that the
comminution tools always have sharp cutting edges in order to
achieve comminution by means of cutting and, to a lesser
degree, by squeezing or breaking or grinding. Sharp
comminution tools have also the advantageous side effect of a
reduced electric energy consumption of the comminution
machine.
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r
During operation of a comminution machine, the
comminution tools are subjected to natural wear. The degree
of wear depends on various factors, for example, the type of
wood and moisture contents of the wood of the starting
materials as well as the advancing speed and circumferential
speed of the cutting tools as well as on constructive
parameters such as the cutting angle and the material
properties of the comminution tools. The strongest wear
effect can be observed on the cutting edges of the
comminution tools which become more and more blunt with
increasing service life so that during the generation of wood
strands a smooth cut can no longer be ensured. This causes
at the same time a decrease of the strand quality, an
increase of the undesirable proportion of fine particles in
the wood strands and, as a result of this, an increase of the
required amount of bonding agent as well as an increase of
energy consumption of the slicing machine.
In order to avoid these disadvantages, it is required to
perform a knife exchange in regular intervals wherein the
worn or spent comminution tools are replaced by resharpened
ones. Under regular conditions such a knife exchange is
carried out in time intervals of three to eight hours. Since
all comminution tools of a knife ring must be exchanged in
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such a knife exchange operation, this requires a considerable
temporal expenditure which causes long downtimes of a
comminution machine. In connection with known methods and
devices for exchanging the comminution tools, which are
performed manually or semi-automatically, a knife exchange
takes approximately 20 to 40 minutes. For an average service
life of the comminution tools of four hours, this causes a
.production loss of three hours per day. Accordingly, the
resulting product loss relative to a nominal strand
production output makes it necessary to design the
comminution device for higher comminution output in order to
ensure the continuous further processing of the produced
strands in the subsequent processing steps. This entails
providing larger bunker capacities as a buffer for bridging
the production loss caused by the knife exchange.
In order to circumvent these disadvantages, attempts
have been made to shorten the duration for a knife exchange.
From German patent application 199 21 383 Al published
November 16, 2000 and U.S. patent 5,313,696, a method and a
device for changing the comminution tools of comminution..
devices are known in which the complete knife ring of the
comminution device is removed and replaced by a second knife
ring furnished with resharpened comminution pools.
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For removing the worn or spent knife ring according to
German patent application 199 21 383 Al published
November 16, 2000, a tool exchange carriage is used which is
moved in front of the end face of the comminution device and
provides together with attachments of the comminution device
a path on which the knife ring, detached from its fastening
means, can be pulled axially out of the housing of the
comminution-device onto the carriage..
For demounting the knife ring, U.S. patent 5,313,696
suggests to arrange it, including its attachment components,
its positioning components, and its drive components, on a
support whose path, extending parallel to the axis of
rotation, enables an axial movement of the complete
comminution unit before the knife ring is removed by means of
a crane and replaced by a newly furnished knife ring.
The disadvantage of these solutions.is that for a knife
exchange the complete knife ring must be exchanged. In
addition to requiring an additional knife ring, this results
in a great technical expenditure, for example, for a tool
change carriage and the elements connected thereto for
coupling the carriage or for a support'for axially pushing
out the complete comminution unit. The labor expenditure for
mounting and demounting the knife ring must be added to the
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time required for exchanging the knives of the knife ring so
that this solution is not satisfactory with respect to
economic efficiency.
How the actual change of the comminution tools, i.e.,
their mounting in and demounting from the knife ring is
carried out,'is not disclosed in these,prior art references.
Suggestions in this respect can be taken from German
patent 41 14 840 C2 published November 12, 1992 describing a
method and a device for exchanging the knives of a knife
ring wherein here the knife ring must first be demounted
from the comminution device and must be placed into a knife
changing device. In this knife changing device an automatic
knife exchange takes place by means of a magazine in which
the knives arranged in the knife ring, after having been
released from their fastening means, are first pushed out
individually and sequentially from the knife ring and are
then transported on a carriage axially to the magazine where
they are placed in the radial direction into the magazine.
In comparison to the prior art known at the time the
invention according to 41 14 840 C2 published
November 12, 1992 was made, this method and this device
provided a significant technological advance.
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>
However, this type of knife exchange is also possible only
with the knife rings being removed from the comminution
device wherein the individual knives are successively
exchanged. The simultaneous exchange of several knives is
not possible with this method and this device.
From German patent 33 09 517 Cl a knife exchange is
known which is possible with the knife ring mounted in the
comminution device. For this purpose, magazines are arranged
at the end face of the knife ring which are in the form of a
roll for steel strip knives or a cassette for disposable
(single-use) knives, wherein the knives are moved by means of
an axially acting advancing device into the knife ring.
These solutions are said to enable a knife exchange even
during operation of a strand-producing chopping device.
A similar approach is also known from German
patent DE 19 26 777 C3. Here a magazine having
dimensions matching those of the knife ring is placed axially
onto the knife ring. After detachment of the fastening means
of the knives in the knife ring they are pushed out
simultaneously with the action of pushing in the resharpened
knives on the other side of the knife ring.
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=
The two last mentioned methods for exchanging the spent
knives of the knife ring has the disadvantage that at the
front side as well as at the backside of the knife ring a
high technical expenditure must be provided in order to push
on one side the resharpened knives into the knife ring and to
remove at the opposite side the spent knives from the knife
ring.
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21182-331E
SUNIIMARY OF THE INVENTION
It is an object of the present invention to
provide a method and a device which enable a completely
automatic knife exchange which can be performed with minimal
technical expenditure within an extremely short period of
time.
In accordance with one aspect of the parent
application, there is provided a method for automatically
exchanging knife units of a knife ring of a knife ring
slicing device, the method comprising the steps of:
a) providing a knife ring with first knife receptacles;
b) providing a knife changing magazine with second knife
receptacles; c) moving the knife changing magazine relative
to the knife ring into a first knife changing position,
wherein in the first knife changing position at least some
of the second knife receptacles of the knife changing
magazine are axially aligned with at least some of the first
knife receptacles of the knife ring; d) releasing worn knife
units arranged in the first knife receptacles from the knife
ring; e) moving the knife units in a first axial direction
out of the knife ring into empty ones of the second knife
receptacles within the knife changing magazine; f) carrying
out a relative movement between the knife changing magazine
and the knife ring until the knife changing magazine and the
knife ring are in a second knife changing position in which
the second knife receptacles provided with resharpened knife
units are aligned with the first knife receptacles in the
knife ring from which the knife units have been removed in
the step e); and g) introducing the resharpened knife units
in a second axial direction opposite the first axial
direction into the first knife receptacles of the knife ring
from which the knife units have been removed in the step e).
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21182-331E
In accordance with the present invention, this is
achieved in regard to the method in that the spent knife
units, after detachment of their fastening means in the
knife ring, are pushed or pulled in the axial direction out
of the knife ring into an empty compartment within the knife
changing magazine and, subsequently, a relative movement
between the knife changing magazine and the knife ring is
carried out until a knife changing position has been reached
in which the knife units which have been resharpened are
aligned with the knife receptacles in the knife ring and the
resharpened knife units are moved from the knife changing
magazine in the opposite direction into the knife ring.
In regard to the arrangement this is achieved
according to the invention in that a unit for releasing and
fastening the knife units in the knife ring is provided, in
that a pushing unit is provided which is arranged axially
opposite the end faces of the knife ring and which is
suitable to transport at least one knife unit positioned in
the knife exchange position axially out of the knife ring
into the knife changing magazine, in that at least one unit
for performing a relative movement between the knife
changing magazine and the knife ring is provided, and in
that an insertion unit is provided which is suitable to
axially push or pull at least one knife unit out of the
knife changing magazine into the knife ring.
In accordance with one aspect of the present
invention, there is provided a knife changing magazine for
automatically changing knife units of a knife ring, the
knife changing magazine comprising areas with knife
receptacles for knife units forming a knife group to be
exchanged at once, wherein the number of areas of the knife
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the end faces of the knife ring and which is suitable to
transport at least one knife unit positioned in the knife
exchange position axially out of the knife ring into the
knife changing magazine, in that at least one unit for
performing a relative movement between the knife changing
magazine and the knife ring is provided, and in that an
insertion unit is provided which is suitable to axially push
changing magazine is greater by at least one than a number
of the knife groups to be exchanged.
In regard to the device for comminuting, this object is
achieved in that the pushing elements are arranged on a
transverse beam onto which the advancing drive acts.
In regard to the knife changing magazine, this is
achieved in that the knife changing magazine has at least one
more receiving area than knife groups to be exchanged
The present invention is based on the principal idea
that a completely automatic exchange of the knife units of a
knife ring is to be enabled without requiring any human
intervention. When carrying out the method, the detection,
governing, and control of the individual operating states of
the method are realized by a programmable automatic sequence
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control.
When personnel is still to be used to some extent, the
knife exchange can also be performed semi-automatically. In
the semi-automatic variant, the knife units are pushed out of
the knife ring only partially and are then removed by hand
from the knife ring and replaced by resharpened knives. This
variant of the invention is suitable in connection with the
device according to the invention having the pushing elements
arranged on a transverse beam onto which the advancing drive
acts.
The automated knife exchange makes the operator of the
comminution machines according to the invention independent
of the possible shortcomings of the employed personnel; often
it is these shortcomings of the personnel that cause damage
to the slicing machines or lower quality of the wood strands.
Moreover, the knife exchange in the past required great
physical expenditure and presented a great risk of injuries
as a result of the great weight and the unwieldy
configuration of the knife units as well as the sharp cutting
edges of the knives. The automation which can be achieved by
means of the invention eliminates a source of injury for the
good and the health of the operating personnel.
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The reduction of the downtime of the comminution
machines when employing the inventive method is of economical
and thus imminent importance for the operator of comminution
machines. Since the knives of comminution machines must be
exchanged four times, or even more frequently, each day, the
time which is saved for each knife exchange by means of the
present invention over the course of time results in a
significant advantage with regard to costs.
The exchange of the knife units according to the
invention can be realized for the mounted as well as
demounted knife ring; this provides great flexibility. The
method according to the invention and the device according to
the invention enable an exchange of groups of knife units
wherein the number of knife units in a group comprises in the
extreme situation at least one knife unit and a maximum of
all knife units of a knife ring. Preferred are however
knife groups which contain one fourth up to one sixteenth of
all knife units of a knife ring so that with a cycle time
between four and 16 a complete exchange of the knife units
can be performed. In this way, an optimum of time savings
and a minimum of constructive expenditure, enabling a compact
design of the comminution machines, are realized.
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The method and the device according to the invention
require only a single knife changing magazine so that the
constructive expenditure is limited to a minimum. This is
enabled in that simultaneously the knife changing magazine is
used as a storage container for the knife units which have
been resharpened for the knife exchange and, on the other
hand, for receiving the worn or spent knives from the knife
ring so that the manufacturing costs relative to other
devices are significantly reduced.
Since the knife exchange substantially is carried out
only at the forward end face of a knife ring and
substantially all components for performing the knife
exchange are arranged here, this configuration also enables
an extremely compact and thus space-saving design. With
respect to servicing and repairs, this has the advantage of
improved accessibility of the device according to the
invention.
For performing a relative movement between the knife
ring and the knife changing magazine after the worn knife
units have been pushed out from the knife ring, a movement of
the knife changing magazines is preferred according to the
invention even though an adjustment of the knife ring would
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be possible. This preference is based on the smaller mass of
the knife changing magazine which therefore enables with a
reduced force expenditure a quicker realization of the
relative movement. For realizing the relative movement,
axial movements or pivot movements of the knife changing
magazines relative to the knife ring are basically also
possible. According to the invention, a horizontal or
vertical displacement possibility is preferred because such a
configuration requires the smallest space and, in this way,
the compact configuration of the device of according to the
invention can be further improved. A vertically performed
relative movement provides, primarily in combination with a
two-level construction of the comminution machine, the
advantage that the knife exchange magazine with spent knife
units during the course of relative movement can be advanced,
for example, to a sharpening device arranged underneath the
comminution machine.
When the exchange of the knife units is not carried out
at once but in a cycled fashion, after each exchange of a
knife group a further relative movement between knife
changing magazine and knife ring must-occur in order to move
a section of the knife ring to be furnished with resharpened
knife units from the knife changing magazine into the
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exchange position so that the old knives of the knife ring
can be received. In principle, this relative movement can
also be performed by the knife changing magazine. However,
it is advantageous to define a fictitious knife changing
position into which the knife changing magazine as well as
the knife ring are moved. While for the knife changing
magazine, as described, a horizontal or vertical adjustment
movement is suggested, the invention prefers in this
connection a rotational movement of the knife ring. In this
way, a decoupling, and thus simplification, of the movement
sequence is realized which also has an effect in regard to a
simplified configuration of the comminution device.
A preferred embodiment of the invention provides that
the knife units during the steps of being pushed out and
being inserted are guided additionally. This is known
primarily in connection with devices in which the knife
changing magazine is arranged at an axial spacing from the
end face of the knife ring. By means of an additional
guiding it is ensured that the knife units reach precisely
the receptacles of the knife ring or of the knife changing
magazine. The guide arrangement therefore contributes
significantly to improving the operational safety.
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The signal for the knife exchange can be realized as a
function of time but also as a function of the quality of the
produced wood strands. The invention prefers however an
energy-dependent control of the knife exchange because, in
this way, the special wear state of the knife units is taken
into consideration.
The operation of a comminution device also entails that
the fine material will deposit within the knife receptacles
of the knife ring. Since the boundary surfaces of the
receptacles are also reference surfaces for the resharpened
knife units, which are adjusted relative to the reference
surfaces with regard to their geometry in order to finally
reach the nominal position, dirt deposits cause a
falsification of the reference surfaces so that the
resharpened knife units are mounted in the knife ring in a
position which deviates from the nominal position. In order
to prevent this, it is suggested according to the invention
to perform a cleaning of the receptacles, and thus of the
reference surfaces of the knife ring, between the steps of
pushing the knife units out of the knife ring and inserting
the resharpened knife units into the knife ring. The
cleaning action can be realized mechanically by means of a
slide which frees the reference surfaces from dirt deposits,
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for example, during insertion of and/or pushing out the knife
units. A slide is suitable, in particular, for cleaning
planar surfaces. Another possibility according to the
invention is provided by generating a fluid flow in the
receptacles of the knife ring. For this purpose, a nozzle
can be arranged at the end of a receptacle where the end face
is or can be introduced together with the pushing unit into
the receptacles. In this way, even locations which are
difficult to access can be cleaned.
A further possibility of cleaning of the receptacle of a
knife ring according to the invention is the use of a milling
brush which is used alone or in combination with the
aforementioned measures.
In order to ensure that the knife units which have been
resharpened are actually mounted in the nominal position
within the knife ring after knife exchange, according to a
special embodiment of the invention it is suggested to
monitor by means of a measuring device the nominal position
of the knife units within the knife ring. In this
connection, the radial projecting length of the cutting edges
of the knife units past the inner wall of the knife ring is
monitored as well as the axial insertion depth of the knife
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21182-331E
units into the knife ring. Only when the control
measurements indicate a proper position of the knife units,
the exchange of the knife units can be continued. In this
way, damage of the comminution machine is prevented which,
for example, could result by a too large radial projecting
length of the cutting edge into the comminution space.
Particularly when carrying out a completely automated knife
exchange, the realization of control measures is of great
importance because.monitoring by an operator, who is capable
of recognizing severe mounting errors of the knife units
with ease, is no longer possible. Ensuring mounting of the
knife units in the nominal position by means of an
additional control measurement significantly increases at
the same time the quality of the produced wood strands.
In accordance with another aspect of the
invention, there is provided a knife changing device for
automatically, group-wise changing knife units of a knife
ring, which knife units are arranged in knife groups
containing at least two knife units, the device comprising a
knife changing magazine with areas with knife receptacles
for receiving knife units of a knife group to be exchanged
at once, the knife units being arranged in an area formed as
a circular arc section, all the knife receptacles in an area
of the knife changing magazine being arranged to correspond
to an arrangement of a corresponding number of knife units
in the knife ring, wherein the number of areas of the knife
changing magazine is greater by at least one than a number
of the knife groups to be exchanged.
The invention will be explained in the following
with embodiments illustrated in the drawings in the form of
a long-cut wood slicing device with rotating knife ring. It
is understood that the invention is not limited to such
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21182-331E
comminution devices; devices are also included which have
comparable comminution tools which are arranged in a tool
ring and axially removed from or inserted into the tool
ring. Screen milling elements or grinding track elements of
mills are mentioned as an example in this context.
19a
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BRIEF DESCRIPTION OF THE DRAWING
In the drawing:
Fig. 1 shows a schematic view of a knife ring slicing
device;
Fig. 2 shows a cross-section along the section line II-
II of the knife ring slicing device with knife changing unit
as illustrated in Fig. 1;
Fig. 3 shows a horizontal section along the section line
III-III of the knife ring slicing device with knife changing
unit as illustrated in Fig. 2;
Fig. 4 shows in partial cross-section a view of the
knife ring slicing device illustrated in Fig. 3 in the area
of the knife changing unit along the section line IV-IV,
wherein a first embodiment of the knife changing unit is
illustrated;
Fig. 5 shows in partial cross-section a view of the
knife ring slicing device illustrated in Fig. 3 in the area
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of the knife changing unit along the section line IV-IV,
wherein a second embodiment of the knife changing unit is
illustrated;
Fig. 6 shows in partial cross-section a view of the
knife ring slicing device illustrated in Fig. 3 in the area
of the knife changing unit along the section line IV-IV,
wherein a third embodiment of the knife changing unit is
illustrated;
Fig. 7 shows in partial cross-section a view of the
knife ring slicing device illustrated in Fig. 3 in the area
of the knife changing unit along the section line IV-IV,
wherein a fourth embodiment of the knife changing unit is
illustrated;
Fig. 8 shows a partial cross-sectional view of a knife
changing unit with integrated cleaning device in detail;
Fig. 9 shows schematically a detail view of a first
embodiment of the coupling between the-pushing element of the
knife changing unit and the knife unit;
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Fig. 10 shows schematically a detail view of a second
embodiment of the coupling between the pushing element of the
knife changing unit and the knife unit;
Fig. 11 shows schematically a detail view of a third
embodiment of the coupling between the pushing element of the
knife changing unit and the knife unit;
Fig. 12 shows schematically a detail view of a fourth
embodiment of the coupling between the pushing element of the
knife changing unit and the knife unit;
Fig. 13 shows schematically a detail view of a fifth
embodiment of the coupling between the pushing element of the
knife changing unit and the knife unit;
Fig. 14 shows schematically a detail view of a sixth
embodiment of the coupling between the pushing element of the
knife changing unit and the knife unit;
Figs. 15a and 15b show schematically a detail view of a
seventh embodiment of the coupling between the pushing
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element of the knife changing unit and the knife unit in two
different positions;
Fig. 16 shows a side view of the pushing element of the
knife changing unit with integrated cleaning nozzles;
Fig. 17 shows a cross-section along the line XVII-XVII
of the pushing element illustrated in Fig. 16;
Fig. 18 shows a view of a movable knife changing
magazine including its drive;
Fig. 19 shows a horizontal section along the line XIX-
XIX of the magazine illustrated in Fig. 18;
Fig. 20 shows a partial view of the knife changing
magazine illustrated in Fig. 18 in the area of the knife
receptacles;
Fig. 21 is a view of a further embodiment of the knife
changing magazine;
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Fig. 22 shows a further arrangement of a knife changing
unit on a knife ring slicing device in a plan view;
Fig. 23 shows a cross-section along the line XXIII-XXIII
of Fig. 22;
Fig. 24 shows a further arrangement of a knife changing
unit on a knife ring slicing device in a plan view;
Fig. 25 shows a cross-section along the line XXV-XXV of
Fig. 24;
Fig. 26 shows a knife ring slicing device with knife
changing unit in a first operating state during the knife
exchange;
Fig. 27 shows the knife ring slicing device with knife
changing unit of Fig. 26 in a second operating state during
the knife exchange;
Fig. 28 shows the knife ring slicing device with knife
changing unit of Fig. 26 in a third operating state during
the knife exchange;
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Fig. 29 shows the knife ring slicing device with knife
changing unit of Fig. 26 in a fourth operating state during
the knife exchange;
Fig. 30 shows the knife ring slicing device with knife
changing unit of Fig. 26 in a fifth operating state during
the knife exchange; and
Fig. 31 shows the knife ring slicing device with knife
changing unit of Fig. 27 in a sixth operating state during
the knife exchange.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fig. 1 shows in a schematic view a knife ring slicing
device 1. The knife ring slicing device 1 has a knife ring 3
arranged within a machine housing 2 which is transversely
movable on a base frame 4 of the machine across the
stationary substructure 5 of the machine in the direction of
the double arrow. The drive of the knife ring 2 is realized
by a drive 6 also arranged on the basic frame 4 of the
machine.
In Fig. 3 the configuration of the knife ring slicing
device 1 is shown in more detail. Also shown is a knife
changing unit 34, required for the knife exchange, in a
simplified illustration. 'Illustrated is the transversely
movable base frame 4 on wheels 24 to which the machine
housing 2 is connected fixedly. The machine housing 2 has at
its front side 7 a central circular opening B. The back wall
23 of the housing 2 however is penetrated by a horizontally
arranged drive shaft 9 which is freely rotatably supported on
a self-aligning roller bearing. The end of the drive shaft 9
outside of the housing 2 supports a disk 10 having several
grooves and connected by means of the drive belt 11 with an
electric motor 12. A braking and indexing disc 13 is mounted
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on the multi-groove disk 10 like an annular flange which is
correlated with a disc brake 14 of the housing 2. In
immediate vicinity to the braking and indexing disc 13 an
initiator 136 is arranged which transmits together with the
braking and indexing disc 13 the respective position of the
multi-groove disc and thus of the knife ring 3 to the
programmed automatic sequence control 39. A knife ring
locking device 37 arranged on the housing 2 is provided in
order to secure a predetermined position of the knife ring 3
relative to the housing 2, as, for example, the knife
changing position.
On the end of the drive shaft 9 positioned in the
housing 2 a support disc 15 is seated coaxial to the drive
shaft 9. The knife ring 3 is detachably fastened on the disc
15.
The knife ring 3 is comprised of a first annular disc 16
and a second concentric annular disc 17 which are connected
to one another by knife carriers 18 which are uniformly
distributed about the circumference and axially aligned and
secured at a spacing to one another. The knife carriers 18
have axial knife receptacles 40, respectively, into which the
knife units 19 are inserted and fastened. The knife units 19
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in the present case are comprised of a slicing knife and a
knife holding plate; however, in principle, they can also be
comprised simply of the slicing knife itself.
In Figs. 1 and 4 through 7, the knife receptacles 40 and
knife units 19 are illustrated only in a simplify
illustration wherein the knife units 19 shown in dash-dotted
line are already pushed out of the knife receptacles 40.
The slicing chamber 20 is formed thus by the support
disc 15 and the circular space surrounded by the knife ring 3
into which the material to be comminuted is introduced in the
axial direction via the opening 8. By rotating the knife
ring 3 about the axis of rotation 21 and a relative movement
between the knife ring 3 and the material to be comminuted by
transverse movement of the base frame 4 of the machine, the
slicing operation is carried out wherein the comminuted
material exits in the radial direction through the knife ring
3 and exits the knife ring slicing device 1 within the
housing 2 through an opening 22 at the bottom side and is
then transported away, for example, by a conveyor belt.
On the front side 7 of the knife ring slicing device 1
at the level of the axis of rotation 21 and axially opposite
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.
a portion of the annular disc 17, a knife changing magazine
25 is arranged which is movable on a stationary substructure
26 along the front side 7 the knife ring slicing device 1.
The stationary substructure 26 for this purpose is provided
at its upper side with two rails 27, a drive 28, as well as a
travel measuring system 29, comprised of an index bolt 40 and
initiators 31. The rails 27 form a path for the wheels 32 of
a carriage 33 which is connected fixedly with the movable
part of the drive 28. The top side of the carriage 33 serves
for receiving the knife changing magazine 25.
The knife changing magazine 25 has a plurality of axial
knife receptacles 45 which can be moved by means of the drive
28 into a position axially aligned with the knife receptacles
40 of the knife carriers 18. Further details of the knife
changing magazine 25 are described in connection with Figs.
19 and 20.
In the area of the back wall 23 of the housing 2, a
section of the annular disc 16 is arranged axially opposed
thereto and a knife changing unit 34 is arranged
approximately at the level of the axis-of rotation 21 and
fixedly attached to the base frame 4 of the machine. The
knife changing unit 34 houses several pushing elements 35 of
29
CA 02505415 2002-05-17
which only one, representative of all the others, is
illustrated in Fig. 2. The pushing elements 35 are supported
axially movably in the knife changing unit 34, and, as
illustrated by arrow 36, can be pushed in the axial direction
out of the knife changing unit 34 and can be introduced
through openings in the back wall 23, the support disc 15,
and the annular disc 16 into the knife receptacles 40 of the
knife carriers 18. In this way, the knife unit 19 positioned
within the knife receptacles 40 is pushed out of the knife
ring 3 and is moved into a knife receptacle 45 (Fig. 20)
within the knife changing magazine 25.
Different embodiments of the knife changing unit 34
described in connection with Figs. 1 through 3 are
illustrated in Figs. 4 through 7. The knife ring slicing
device 1 corresponds to the knife ring slicing device 1
illustrated in Figs. l through 3 so that the reference
numerals used therein are also employed in Figs. 4 to 7. In
contrast to the knife ring slicing device illustrated in
Figs. 1 through 3, the embodiment illustrated in Figs. 4
through 7 of the invention has no knife changing magazine at
the front side 7 of the knife ring slicing device 1 and is
suitable therefore particularly for performing a semi-
automatic method for changing the knife units 19 in which
CA 02505415 2002-05-17
individual knife units 19 or groups of knife units 19 are
pushed only partially out of the knife receptacles 40 of the
knife ring 3 and are then completely removed by hand and
replaced by knife units 19' which have been resharpened.
By combining or supplementing such a semi-automatic
embodiment of the invention with a knife changing magazine 25
and an insertion unit, a completely automated arrangement for
changing the knife units 19 of the knife ring 3 results.
The knife changing unit 34 illustrated in Fig. 4 is
comprised of a frame which is formed by an inner rectangular
plate 48 and an opposed rectangular plate 49 positioned at a
spacing thereto. Both plates 48 and 49 are connected fixedly
with the base frame 4 of the machine; the plate 48 is
additionally connected with the back wall 23 of the machine
housing 2. The two plates 48 and 49 are connected with one
another by guide elements arranged on each corner,
respectively. Moreover, the plates 48 and 49 provide a
central rotary bearing for a spindle 51 extending between the
plates 48 and 49. The spindle 51 is driven at its end by a
drive 52.
31
CA 02505415 2002-05-17
Slidable guide bushings 53 are provided on the guide
elements 50 and are connected to one another by a transverse
beam 54 arranged parallel to the plates 48 and 49. At the
center of the transverse beam 54 a spindle nut 55 is fastened
which is seated on the spindle 51. Moreover, pushing
elements 35 are arranged axis-parallel to the spindle 51 on
the transverse beam 54 and are moveably supported with their
free ends in bores in the plate 48.
By rotation of the spindle 51, the spindle nut 55 and
together with it the transverse beam 54 are moved toward or
away from the knife ring 3, depending on the rotational
direction, as illustrated by the double arrow. In this way,
the pushing elements 35 can be introduced via corresponding
bores in the back wall 23 of the housing 2 and in the support
disc 15 as well as the annular disc 16 into the knife
receptacles 40 within the knife ring 3. Here they impact on
the knife units 19 and move them in the axial direction at
the front side of the knife ring 3 out of the knife
receptacle 40. This state of the knife units 19 is
illustrated in dashed lines in Figs. 4-through 6.
32
CA 02505415 2002-05-17
A slight variation of the embodiment illustrated in Fig.
4 is shown in Fig. 6 so that for same parts the same
reference numerals are used.
Instead of a central spindle, two parallel spindles 56
and 57 are used which are arranged between the pushing
elements 35 and which are driven in the way described above
for movement of the transverse beam 54 by means of a
synchronizing drive. In this way, the transverse beam 54
glides along the outer guide elements 50.
A further embodiment of the knife changing unit 34, as
illustrated in Fig. 5, has two outwardly positioned spindles
58 and 59, which form, in addition to the centrally arranged
guide element 60, also a guide for the transverse beam 54.
Pushing out or inserting the pushing elements 35 is also
realized by synchronously driving the spindles 58 and 59.
The knife changing unit 34 illustrated in Fig. 7
provides a simplification of the knife changing unit 34
illustrated in Fig. 4. In this embodiment, the externally
positioned guide elements for the transverse beam 54 are
eliminated. Instead, a spindle 61 arranged axis-parallel to
33
CA 02505415 2002-05-17
the axis of rotation 21 is fastened on two bearing plates 62
and 63. The lower pushing elements 35 are moveably supported
in two bores of the bearing plate 63 positioned opposite the
housing 2, and, in this way, rotation of the transverse beam
54 and of the pushing elements 35 is prevented. In this
embodiment of the invention, the spindle 61 provides the
advancing function as well as the guiding function.
Fig. 8 shows a partial cross-section of the area in
which the pushing elements 35 penetrate the knife ring
slicing device 1. A section of the back wall 23 of the
housing 2 is shown as well as a section of the support disc
15 arranged at a spacing thereto and fixedly connected with
the annular disc 16. At the inner side of the annular disc
16, the end of a blade unit 19 at the end face is illustrated
which is introduced into a knife receptacle 40 of a blade
carrier 18 (not illustrated in detail) and rests with its end
face against the lateral surface of the annular disc 16. The
support disc 15 and the annular disc 16 as well as the back
wall 23 of the housing 2 have an aligned bore 64, 64' which
extend directly to the end face of the knife unit 19.
Extending from the left edge of the sheet, the forward
end of a pushing element 35 is illustrated which has already
34
CA 02505415 2002-05-17
penetrated the back wall 23 of the housing 2 and whose tip is
in a position immediately before penetration of the bore 64
of the support disc 15. Upon further insertion of the
pushing element 35, its tip reaches the end face of the knife
unit 19 and forces it out of the knife receptacle 40 since
the pushing element 35 continues to be driven.
In addition, a cleaning device for cleaning the knife
receptacle 40 in the knife carrier 18 during the process of
pushing out the knife unit 19 is illustrated in Fig. 8. A
sealing element 65 is screwed onto the left side, in the
plane of the illustration, of the back wall 23 and provides a
seal-tight enclosure of the pushing element 35 even during
the advancing movement. On the opposite.side of the back
wall 23 of the housing 2 a nozzle 66 is arranged whose
hollow-cylindrical end 67 projects to the bore 64 in the
support disc 15. The nozzle base 68 is widened for forming a
chamber and has a penetration 69 for loading the nozzle 66
with a fluid flow. The cleaning nozzle 66 surrounds with its
hollow-cylindrical portion 67 the pushing element 35 with a
minimal annular gap 70 being provided between the portion 67
and the pushing element 35. When loading the nozzle 66 with
a fluid under pressure, a fluid flow results in the annular
gap 70 and extends further along the mantle surface of the
CA 02505415 2002-05-17
pushing element 35. In this way, a cleaning action of the
knife receptacles 40 during knife exchange takes place with
the insertion of the pushing element 35 into the knife
receptacles 40.
According to one embodiment of the invention, the knife
changing unit 34 is of a unitary configuration, i.e., the
knife units 19 are moved out of the knife receptacles 40 of
the knife ring 3 from one side of the knife ring, and the
insertion of the resharpened knife units 19' from the knife
changing magazine 25 into the receptacles 40 of the knife
ring 3 is carried out also from the same side (Figs. 2 and 3
and Figs. 22 and 23).
In these situations, it is required to provide a
pulling-resistant connection between the pushing elements 35
and the knife units positioned in the knife receptacles of
the knife changing magazine 25. Different solutions are
illustrated in Figs. 9 through 15 with which a pulling-
resistant and pushing-stable connection between the pushing
element 35 and the blade unit 19, 19' can be provided.
In Figs. 9 through 15 the leading end of a pushing
element 35 is illustrated onto which a coupling head 71 is
36
CA 02505415 2002-05-17
positioned, respectively. Fig. 9 shows the coupling head 71
comprised of a truncated cone portion which is introduced
into a matching truncated cone-shaped receptacle in the end
face.of the knife unit 19, 19'. As a result of the slant of
the lateral surfaces of less than 2 relative to the mantle
surface of the pushing element 35, a frictional connection
results which is loadable with regard to pressure as well as
9
tension. Releasing this connection is realized by contacting
a surface 72. This causes the clamping force produced by the
frictional connection to be overcome so that the truncated
cone and thus the pushing element 35 come free.
In an alternative connecting possibility (Fig. 10), the
coupling head 71 has one or several radial bores 73 into
which a pressure spring 47 is introduced and on which, in
turn, a ball 75 is seated as a locking element. The opening
of the bore 73 is slightly narrowed so that the ball 75 is
captive in the bore.
In the end face of the knife element 19, 19' a
cylindrical recess is provided which has at its inner side an
annular groove 76. Upon insertion of the pushing element 35
into the recess of the knife element 19, 19', first the ball
75 is radially pushed against the spring force and
37
CA 02505415 2002-05-17
subsequently snaps into place in the annular groove 76 of the
knife unit 19, 19' upon further insertion of the pushing
element 35.
The coupling head 71 of Figs. 11 and 12 is provided with
a solenoid or permanent magnet 78. The magnet or solenoid
can be connected directly with the smooth end face of a knife
unit 19, 19' (Fig. 11) or can be introduced into a recess,
matching the solenoid or magnet shape, in the end face of the
knife unit 19, 19' (Fig. 12).
The solution illustrated in Fig. 13 shows the knife unit
19, 19' having a cylindrical recess 79 on whose inner side
the spring elements 80, already described in connection with
Fig. 10, are arranged in a common radial plane. These spring
elements 80 snap into place with their ball-shaped latch in
an annular groove 93 in the coupling head 71 of the pushing
element 35.
In the connection illustrated in Fig. 14 between the
pushing element and the knife unit 19, 19' a nonpositive
connection by means of positive fit is obtained. For this
purpose, the coupling head 71 has a groove 82 into which a
projection 83 of the knife unit 19, 19' engages. For
38
CA 02505415 2002-05-17
producing the positive fit connection, the coupling head 71
is introduced perpendicularly to the plane of illustration
into the recess in the knife unit 19, 19' or is rotated about
its longitudinal axis.
A further possibility of providing a pull-resistant
connection between the pushing element 35 and the knife unit
19, 19' is described in connection with Figs. 15a and 15b.
The knife unit 19, 19' illustrated therein has at its end
face a cylindrical recess in whose mantle surface an annular
groove 84 is provided. The coupling head 71 has a ball 86
which is moveably arranged within a radial guide and serves
as a latch; it cooperates with the annular groove 84 of the
knife unit 19, 19'. For actuating the ball 86, an axially
movable control element 87 is provided within the coupling
head 71. It can be separately controlled and has two glide
surfaces 81 and 85 for the ball 86 which are positioned at
different levels relative to one another and connected by a
ramp. A pressure spring 88 acts between the end of the
coupling head 71 and the end of the control element 87 at the
end face.
By coaxial movement of the control element 87 counter to
the spring force of the coil spring 88, the ball 86 is pushed
39
CA 02505415 2002-05-17
radially outwardly by the glide surface 81 via the ramp and
the glide surface 85 and snaps into place in the annular
groove 84 of the knife unit 19, 19'. A release of the
locking action is realized in the reverse order so that by
axial movement of the control element 87 in the direction of
the spring force a lowering of the ball 86 onto the lower
glide surface 81 of the control element 87 is possible and
the annular groove 84 is released in this way.
Figs. 16 and 17 show an alternative or additionally
embodiment of the cleaning device relative to Fig. 8 for the
knife receptacles 40 in the knife ring 3. The pushing
element 35 is illustrated which is in the form of a hollow
cylinder and which is moved into a nonpositive connection
with a knife unit 19 by means of the coupling head 71
described in connection with Figs. 9 through 15. In the
vicinity of the coupling head 71 radially acting cleaning
nozzles 90 are arranged. They are connected via the hollow
cylinder of the pushing element 35 to the cleaning system
which ensures the exit of a cleaning fluid and/or a gas, for
example, air, out of the nozzles 90 at high pressure.
Fig. 17 shows also a part of the knife carrier 18 in the
area of the knife receptacle 40. In the dashed illustration
CA 02505415 2002-05-17
a part of the knife unit 19 is shown in a position in which
it is arranged in the knife receptacle 40 during the pushing
out movement. Moreover, Fig. 18 shows the bore in the
annular disc 26, which bore is identified by reference
numeral 64 in Fig. B. The pushing element 35 reaches the
knife receptacles 40 in the knife carrier 18 via the bore 64.
Figs. 18 and 19 show details of the configuration of the
knife changing magazine 25 including the adjusting device 95
for horizontal adjustment of the knife changing magazine 25
into the knife changing position.
The knife changing magazine 25 is comprised
substantially of the lateral parts 96 and 97 which are
arranged parallel and at a spacing to one another. The
lateral parts 96 and 97 are connected rigidly by means of
bolts 98 provided at the corners. The lateral parts 96 and
97 have a plurality of slot-shaped recesses 99. The recesses
99 are arranged above one another and form groups wherein the
individual groups are arranged on parallel circular arc
sections. The number of recesses 99 of a circular arc
section corresponds to the number of pushing elements 35 of
the knife changing unit 34 and thus to the number of knife
units 19 which can be changed simultaneously by a single
41
CA 02505415 2002-05-17
exchange operation. The slants of the recesses 99 of a
circular arc section changes from recess 99 to recess 99 and
correspond exactly to the slant of the knife units 19 mounted
in the knife ring 3. The recesses 99 in the lateral part 96
are arranged congruently with the recesses 99 in the lateral
part 97.
Between two oppositely positioned recesses 99 of the
lateral parts 96 and 97, angle elements 100 and 101 (Fig. 20)
connecting the recesses 99, respectively, are inserted whose
legs form gliding and stop surfaces for the knife unit 19,
19'. In this way, the angle elements 100 and 101 as well as
the lateral parts 96 and 97 including the recesses 99 provide
a plurality of knife receptacles 45 in the knife changing
magazine 35 into which the knife units 19, 19' can pushed or
from which they can be removed.
For the knife exchange method according to the
invention, the total number of knife receptacles 45 is based
on the number of knife units 19 to be exchanged plus the
number of knife receptacles 45 required for the number of
knife units 19 of a group to be simultaneously exchanged.
Because of this, in Figs. 18 and 19 additional knife
receptacles 45 of a circular section are without resharpened
42
CA 02505415 2002-05-17
knife units 19' while the other knife receptacles 45 are
provided with resharpened knife units 19'.
Such a knife changing magazine 25 is moved by means of
the adjusting device 95 into the suitable knife changing
position. The adjusting device 95 has a carriage 33 which
can be linearly moved on a stationary substructure 26 as
indicated by the arrow 102. A centering bolt 119 projects
from the plane top side of the carriage 33 and matches a
recess in the underside of the knife changing magazine 25.
The carriage 33 is driven by a drive 28 which is, for
example, a spindle drive, a toothed rack drive, a chain drive
or the like.
The adjusting device 95 also includes a travel measuring
system 29 which is comprised of a strip stationarily arranged
relative to the substructure 26 and provided with initiators
31. The initiators 31 cooperate with index bolts 30 provided
on the carriage 33.
For the knife exchange operation a knife changing
magazine 25 furnished with resharpened=knife units 19' is
placed by means of a crane 103 onto the carriage 33, wherein
a centering of the knife changing magazine 25 relative to the
43
CA 02505415 2002-05-17
carriage 33 is realized by means of the centering bolt 119.
The stationary substructure 26 and the travel measuring
system 29 form a stationary unit relative to the knife ring
slicing device 1 so that, by means of the height of the
substructure 26 and the position of the carriage 33,
determined by the travel measuring system 29, a precise
positioning of the knife changing magazine 25 relative to the
knife ring slicing device 1 can be realized.
Fig. 21 shows an alternative embodiment of a knife
changing magazine 25. It is comprised of two opposed
coaxially positioned, spaced apart rings of which in Fig. 21
only one is illustrated and identified with reference numeral
104. The two rings have recesses wherein oppositely arranged
recesses are connected with one another in the axial
direction by means of gliding and guiding elements so that in
this way axial knife receptacles are formed in the knife
changing magazine 25. The arrangement of the knife
receptacles corresponds exactly to the arrangement of the
knife units 19 in the knife ring 3 of the knife ring slicing
device 1. Also shown are contact surfaces 105 uniformly
distributed about the outer circumference.
44
CA 02505415 2002-05-17
The carriage 33 has at its top side two axial, freely
rotatable rollers 106 and 107 which are provided for
supporting and simultaneously centering the knife changing
magazine 25. Moreover, a cylinder/piston unit 108 is
connected to the top side of the carriage 33 whose movable
piston upon being extended impacts on a contact surface 105
and in this way causes the knife changing magazine 25 to be
rotated in order to bring a neighboring ring section into the
knife changing position.
Fig. 22 and Fig. 23 show an alternative embodiment of
the invention. The illustrated knife ring slicing device 1
corresponds to that illustrated in Figs. 1 through 3 so that
identical reference numerals are used and reference is being
had to the corresponding description. Differences reside
only in the arrangement of the knife changing unit 34 which
in Figs. 22 and 23 is arranged at the front side 7 with
intermediate positioning of the knife changing magazine 25
instead of opposite the back wall 23 of the knife ring
slicing device 1. The knife changing unit 34 illustrated in
Figs. 22 and 23 has also pushing elements 35 which can be
brought into a pull-resistant and push-resistant connection
with the knife units 19, 19' so that the knife units 19, 19'
can be pushed as well as pulled by the knife changing unit 34
CA 02505415 2002-05-17
which is illustrated by arrow 109. The knife exchange is
carried out in this embodiment only from one side of the
knife ring 3.
Since in this variant the pushing elements 35 of the
knife changing unit 34 no longer are introduced into the
knife receptacles 40 in the knife ring 3, cleaning of the
knife receptacles 40 by means of the pushing elements 35 is
no longer possible. For this reason, special cleaning
elements 110 are arranged at the back wall 23 of the knife
ring slicing device 1 which can be guided in the axial
direction through the back wall 23 into the interior of the
machine housing 2. The cleaning elements 110 are provided
with several cleaning nozzles with which a cleaning liquid
and/or a gas, for example, air, can be supplied at high
pressure into the knife receptacles from the inner side as
well as the outer side of the knife carriers onto the knife
ring 3.
Figs. 24 and 25 show further embodiments of the
invention wherein, as a result of the identical configuration
of the knife ring slicing device 1, the same reference
numerals as in Figs. 1 through 3 are employed and reference
is being had to the corresponding part of the description.
46
CA 02505415 2002-05-17
The knife changing unit illustrated in Figs. 24 and 25
is divided into two spatially separate units. On the back
wall 23 of the knife ring slicing device 1 the pushing unit
111 is arranged which carries out only the pushing movement
for moving the knife units 19 out of the knife ring 3 into
the knife changing magazine 25. On the opposite side behind
the knife changing magazine 25 the insertion unit 112 is
arranged which realizes the pushing movement for moving the
resharpened knife units 19' out of the knife changing
magazine 25 into the empty knife receptacles 40 in the knife
ring 3. The arrows 113 and 114 show in which direction the
pushing unit 111 or the insertion unit 112 acts.
In this variant it is possible to integrate cleaning
nozzles 90 into the pushing elements 35 of the pushing unit
111 so that the pushing-out movement for moving the knife
units 19 out of the knife ring 3 can realize at the same time
a cleaning of the knife receptacles 40.
Figs. 26 through 31 show different operating states of
the invention when performing a knife exchange. By means of
Figs. 26 to 31 the method according to=the invention will be
explained in the following in more detail by means of a two-
part knife exchange unit comprised of a pushing unit 111 and
47
CA 02505415 2002-05-17
an insertion unit 112. The individual method steps are
triggered by a programmable automatic sequence control which
receives all of the data provided by the sensors and
processes them and calculates based thereon control commands
which are then sent to the knife ring slicing unit 1 and the
components necessary for the knife exchange.
Figs. 26 and 27 show the initial position of a knife
ring slicing device 1 with the pushing unit 111, the
insertion unit 112, as well as the knife changing magazine 25
in the position A. In the initial position for the knife
exchange the knife ring 3 has been moved into a knife
changing position. This is realized by a slow rotation of
the knife ring 3 by the drive 6 until the braking and
indexing disc 13 in connection with the initiator 36 and the
disc brake 14 stops the knife ring 3 in a position in which
the knife receptacles 40 in the knife ring 3 are axially
aligned with the pushing elements 35 of the pushing unit 111
(see also Fig. 3). The knife pushing unit 111 is comprised
in the present embodiment of several cylinder/piston units
arranged in a circular arc pattern and fastened on the back
wall 23 of the knife ring slicing device 1. Their movable
pistons form the pushing elements 35. In the initial
position the pushing elements 35 are retracted into-the
48
CA 02505415 2002-05-17
cylinders.
The knife changing magazine 25 corresponds to that
described in Figs. 18 to 20. The knife changing magazine 25
is furnished with the same number of resharpened knife units
191 as are present within the knife ring 3. The resharpened
knife units 19' are grouped in the knife changing magazine 25
in adjacently positioned circular arc sections. In addition,
the knife changing magazine 25 has empty knife receptacles 45
which correspond to the number of knife units 19 of a
circular arc section.
The knife changing magazine 25 is deposited onto the
carriage 33 and by means of the drive 28 and the travel
measuring system 29 is moved into the knife changing position
where the empty knife receptacles 45 of the knife changing
magazine 25 are axially aligned with the knife receptacles 40
in the knife ring 3 and the pushing elements 35 of the
pushing unit 111.
The insertion unit 112 arranged behind the knife
changing magazine 25 has, in principle; the same
configuration as the pushing unit 111. The insertion unit
112 is fastened on a column 115 fixedly connected to the
49
CA 02505415 2002-05-17
substructure 5 of the machine wherein the insertion elements
116 are retracted into the cylinders.
Fig. 28 shows the next method step in which the
programmable automatic sequence control telescopes the
pushing elements 35 out of the pushing unit 111 wherein they
are moved through the openings in the back wall 23 of the
knife ring slicing device 1 and openings in the support disc
15 and the annular disc 16 into the knife receptacles 40 in
the knife ring 3. Here, the pushing elements 35 impact on
the end face of the knife units 19 previously detached from
the fastening means of the knife carriers 18 and push them in
the axial direction out of the knife ring 3 in the direction
of the free receptacles 45 in the knife changing magazine 25.
In order to bridge the spacing between the knife ring 3 and
the knife changing magazine 25, at the front side 7 of the
housing 2 guide elements 117 (Fig. 27) are arranged which
align the knife units 19 precisely with the free knife
receptacles 45 of the knife changing magazine 25. The worn
knife units 19 are pushed by the pushing elements 35 to such
an extent until they are received completely by the knife
changing magazine 25. Subsequently, the pushing elements 35
are retracted into their initial position.
CA 02505415 2002-05-17
Already during the pushing movement of the pushing
elements 35 and optionally also during the return movement
the knife receptacles 40 in the knife ring 3 are cleaned by
cleaning nozzles 66 (Fig. 8) and optionally by further
cleaning nozzles in the head area of the pushing elements
(Figs. 16 and 17) with a water/air mixture at high pressure.
In the next step, as illustrated in Fig. 29 by the arrow
119, the knife changing magazine 25 is moved to the side by
one cycle. Now the first circular arc section with the
resharpened knife units 19' is in the knife changing position
and aligned with the empty and cleaned knife receptacles 40
in the knife ring 3. The amount by which the knife changing
magazine 25 must be laterally moved is determined by the
travel measuring system 29 and this information is supplied
to the programmable automatic sequence control which controls
the advancement of the carriage 33 accordingly.
Fig. 30 shows the next method step in which the
insertion elements 116 of the insertion unit 112 are advanced
in the direction of arrow 119 wherein they impact on the end
face of the resharpened knife units 19.', positioned in the
knife changing magazine 25, and move the knife units 19' via
the guide elements 117 into the free and cleaned knife
51
CA 02505415 2002-05-17
receptacles 40 in the knife ring 3 until the knife units 19'
contact with the oppositely positioned end face the annular
disc 16. Subsequently, the insertion elements 116 are
retracted into their rest position. At the same time, the
nominal position of the knife units 19' being inserted
momentarily is monitored by means of non-represented sensors
being part of a control unit. For example, the sensors can
be photo diodes or ultrasound distance measuring devices or
infrared distance measuring devices. Only when the control
device affirms the nominal position of the blade units 19',
the knife units 19' are fastened by generally known fastening
devices in the knife ring 3.
The next and last method step of a knife changing cycle
is illustrated in Fig. 31 where the arrow 12 shows the
rotation of the knife ring 3 about the axis of rotation 21.
In this connection, the circular arc section of the knife
ring 3 which has just been provided with the resharpened
knife units 19' is moved out of the knife changing position
wherein at the same time a neighboring circular arc section
of the knife ring 3, which contains worn knife units 19, is
moved into the knife changing position. The amount of
rotation of the knife ring 3 is again determined by the
braking and indexing disc 13 and by means of the initiators
52
CA 02505415 2002-05-17
136. In this position, the first cycle for exchanging a
group of knife units is completed, and a new cycle for
exchanging the next group of knife units is carried out
according to the already described one in connection with
Figs. 27ff.
These process steps are continued until all worn knife
units 19 of the knife ring 3 have been replaced with the
resharpened knife units 19' of the knife changing magazine
25. This situation is illustrated in Fig. 26 by the position
B of the knife changing magazine 25. From this position the
knife changing magazine 25 containing the spent or worn knife
units 19 is removed by means of a crane to a resharpening
station.
While specific embodiments of the invention have been
shown and described in detail to illustrate the inventive
principles, it will be understood that the invention may be
embodied otherwise without departing from such principles.
53
