TECHNICAL FIELD
[0001] The present invention relates to the field of machines for processing logs of web
material, in particular, but without limitation, logs of paper, for instance, although
without limitation, tissue paper or the like for producing toilet paper, kitchen towels
and the like.
BACKGROUND ART
[0002] In many industrial fields, for the production of rolls of wound web material, logs
of significant axial dimensions are produced and are subsequently cut into smaller
rolls, i.e. into rolls of smaller axial dimension intended for packaging and sale.
Typical examples of this kind of processing are in the field of tissue paper converting,
for producing rolls of toilet paper, kitchen towels and the like. In this field, plies
of cellulose material are produced by means of continuous machines and wound into
so-called parent reels. These latter are then unwound and wound again in rewinding
machines, to form logs, the axial length whereof corresponds to the width of the ply
produced by the paper mill and is equal to a multiple of the axial length of the products
to be marketed.
[0003] Then, saw machines are used to cut the logs into rolls of smaller axial dimensions,
intended for packaging and marketing. Examples of saw machines of this type are disclosed
in
US6786808,
US5522292,
US20060000312,
US20060011015, and
WO201603125. The saw machines for logs of wound web material, especially tissue paper, typically
comprise a feeding path for the logs to be cut and a cutting head arranged along the
feeding path. The cutting head comprises one or more disc-shaped cutting blades, which
rotate around their axis and are also provided with a cyclical movement (a rotating
or oscillating movement, for instance) to cut sequentially the logs of greater axial
dimensions, fed along the feeding path, into single subsequent rolls.
[0004] The disc-shaped cutting blades are subject to wear and therefore require to be often
ground. When it is ground, the disc-shaped cutting blade is gradually eroded, with
a consequent reduction of its diameter. When the minimal diameter dimension is achieved,
the disc-shaped cutting blade shall be replaced.
[0005] The cutting blade is usually ground by means of two grinding wheels pressed against
opposite sides of a circular cutting bevel of the disc-shaped cutting blade. The grinding
wheels may be motorized, i.e. driven into rotation by means of respective motors,
for example electric or pneumatic motors. In other embodiments, the grinding wheels
are supported idle and driven into rotation by friction between the active surface
of the grinding wheel and the blade surface to be ground.
[0006] Grinding is crucial, as it affects both the useful life of the blade and the cutting
quality. For example, a non-optimal repeated grinding causes a nonuniform consumption
of the disc-shaped cutting blade, a consequent worse cutting quality and the deformation
of the disc-shaped cutting blade, the cutting edge whereof tends to lose its round
shape and to become polygonal. The useful life of a disc-shaped cutting blade significantly
decreases as the cutting edge thereof becomes polygonal in shape.
[0007] WO-A-01/36151 discloses a grinding device for a log saw according to the preamble of claim 1. The
grinding device comprises two grinding wheels which are arranged on opposite sides
of a cutting edge of the disc-shaped cutting blade. The two grinding wheels are driven
into rotation by contact friction with the disc-shaped blade and by air jets generated
by air nozzles.
[0008] US-A-2006/0162522 discloses a log saw provided with three disc-shaped cutting blades. Each cutting
blade is in turn provided with a grinding unit, comprised of two motorized grinding
wheels.
[0009] GB-A-2171345 discloses a sharpening device for a disc knife for use in a cigarette manufacturing
machine. The sharpening device is comprised of two grinding members. The grinding
members are motor-driven and have different shapes and dimensions. They are arranged
with their rotation axes falling outside the circular cutting edge of the disc knife.
A first grinding member has an annular cup form and is provided with a grinding surface
at its rim. The rim surrounds a hollow. The second grinding member is a grinding wheel,
which has its axis of rotation inclined to that of the cup-shaped annular grinding
member. The diameter of the grinding wheel is substantially smaller than the diameter
of the grinding rim of said cup-shaped grinding member. Thus, a portion of the grinding
wheel enters the a hollow of the cup formed grinding member when the grinding wheel
enters the a hollow of the cup formed grinding member when the two grinding members
are in contact with the two opposite sides of the cutting edge of the disc knife.
[0010] Grinding is provided for also in other fields, e.g. in food slicers.
WO-A-00/40367 discloses a sharpener assembly for a food slicer. The sharpener comprises two grinding
wheels. The two grinding wheels are made of different materials such that one wheel
is more aggressive and the other is less aggressive and is used for truing. To properly
perform their operation, the two grinding wheels are arranged with respect to the
disc blade such that the speed vectors of the two wheels are oriented in opposite
directions with respect to the cutting edge of the disc blade. Specifically, one of
the wheels is arranged such that the relative velocity vector is oriented outwards
with respect to the cutting edge.
[0011] It is therefore useful to provide improvements to the saw machines and, especially,
to the grinding systems thereof, as well as to the grinding methods.
SUMMARY OF THE INVENTION
[0012] According to the invention a log saw machine is provided, comprising a feeding path
for the logs to be cut and a cutting head arranged along the feeding path. The cutting
head comprises a disc-shaped cutting blade rotating around a rotation axis and provided
with a cyclical movement for cutting the logs. The cutting head also comprises two
grinding wheels, which are arranged and configured to grind two sides of a cutting
edge of the disc-shaped cutting blade, and each of which rotates around its rotation
axis. The grinding wheels are so arranged, with respect to the disc-shaped cutting
blade, that, in a contact area between each grinding wheel and the disc-shaped cutting
blade, the grinding wheel has a velocity directed towards the inside of the cutting
edge. In other words, the contact area between the grinding wheel and the respective
side of the cutting edge has a velocity represented by a vector directed towards the
inside of the cutting edge instead of towards the outside thereof. If this relative
motion condition occurs for both the grinding wheels, a more regular grinding is provided,
as well as a better cutting quality.
[0013] The grinding wheels are so arranged, with respect to the disc-shaped cutting blade,
that the contact areas between the grinding wheels and the disc-shaped cutting blade
are arranged between two approximately parallel planes, each of which contains the
rotation axis of one of the grinding wheels. The planes are approximately parallel
to a plane containing the rotation axis of the disc-shaped cutting blade.
[0014] The grinding wheels are supported idle and driven into rotation by friction with
the disc-shaped cutting blade thanks to the torque generated on the grinding wheels
by the friction between these latter and the disc-shaped cutting blade.
[0015] In advantageous embodiments, the two contact areas between the grinding wheels and
the disc-shaped cutting blade are symmetrical with respect to a plane containing the
rotation axis of the cutting blade and extending between the rotation axes of the
two grinding wheels.
[0016] According to some embodiments, the two grinding wheels may be so arranged that, when
they are in an operative position into contact with the disc-shaped cutting blade,
the rotation axis of a first of said two grinding wheels is arranged outside the cutting
edge of the disc-shaped cutting blade, and the rotation axis of the other of said
two grinding wheels is arranged inside the cutting edge so as to intersect the disc-shaped
cutting blade.
[0017] According to the invention, a method of grinding a disc-shaped cutting blade of a
saw machine for cutting logs of web material is provided. The method is defined in
claim 5.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The invention shall now be more apparent by following the description and accompanying
drawing which shows a practical embodiment of the invention. More in particular, in
the drawing:
Figure 1 is a partial schematic side view of the main members of an embodiment of
a saw machine;
Figure 2 is a sectional view, according to a vertical plane, of the head of the saw
machine of Figure 1, with the disc-shaped cutting blade and the grinding wheels;
Figure 3 is an enlarged cross-section of the grinding wheels near the blade cutting
edge according to the plane III-III of Figure 4; and
Figure 4 schematically shows the position of the grinding wheels and the disc-shaped
cutting blade according to the arrow IV of Figure 3.
DETAILED DESCRIPTION OF EMBODIMENTS
[0019] The following detailed description of the exemplary embodiments refers to the accompanying
drawings. The same reference numbers in different drawings identify the same or similar
elements. Additionally, the drawings are not necessarily drawn to scale. Also, the
following detailed description does not limit the invention. Instead, the scope of
the invention is defined by the appended claims.
[0020] Reference throughout the specification to "one embodiment" or "an embodiment" or
"some embodiments" means that the particular feature, structure or characteristic
described in connection with an embodiment is included in at least one embodiment
of the subject matter disclosed. Thus, the appearance of the phrase "in one embodiment"
or "in an embodiment" or "in some embodiments" in various places throughout the specification
is not necessarily referring to the same embodiment(s). Further, the particular features,
structures or characteristics may be combined in any suitable manner in one or more
embodiments in accordance with the appended claims.
[0021] Figure 1 schematically shows the main members of a saw machine 1, that may comprise
the novel features described herein for the grinding system. It should be understood
that the structure of the saw machine can be different from the one briefly described
herein. For instance, different drive means can be provided for transmitting the advancing
motion of the logs and of the disc-shaped cutting blade. This latter can be provided
with a reciprocating motion, for instance a pivoting motion, instead of a continuous
motion. Moreover, the cutting head of the saw machine may comprise more disc-shaped
cutting blades.
[0022] The saw machine 1 illustrated herein comprises a feeding path schematically indicated
with P, along which the logs L, that shall be cut into rolls R of smaller axial dimension,
move forward. The rolls are then fed to packaging machines, not shown. The saw machine
is arranged downstream of a rewinding machine and of further processing stations,
not shown and known by those skilled in the art.
[0023] In some embodiments, the saw machine 1 comprises a cutting station 3, which in turn
comprises a cutting head schematically indicated with number 5. The cutting head 5
may comprise an orbital head 7 rotating around the rotation axis A-A, which may be
generally oriented approximately in the same direction as the feeding path P for the
logs L to be cut. The orbital head 7 of the cutting head 5 carries at least one disc-shaped
cutting blade 9, which can rotate around a rotation axis B-B. The rotation axis B-B
of the disc-shaped cutting blade 9 may be generally oriented approximately in the
direction of the axis A-A. As known by those skilled in the art, there are saw machines
where the axes A-A and B-B are not perfectly parallel to each other and/or to the
feeding direction along the feeding path PA for the logs to be cut. This is due to
some features of the saw machine that are not relevant to the present description
and relate to the relative movements between the cutting head 5 and the forward movement
of the logs L to be cut.
[0024] The saw machine 1 can comprise a motor 11 providing the disc-shaped cutting blade
9 with the rotary motion, and a further motor 13, providing the cutting head 5 and
the orbital head 7 with the rotary motion around the axis A-A.
[0025] The logs L can move forward according to the feeding path PA along one or more lanes
parallel to one another, so as to cut simultaneously more logs and increase the productivity
of the saw machine 1, as known by those skilled in the art.
[0026] The forward movement of the logs L may be provided, for instance, by means of a continuous
flexible member 15, such as a chain or a belt, driven by a motor 17. Advantageously,
the motors 11, 13, and 17 can be controlled by a central control unit 19, in a manner
known to those skilled in the art and not described in greater detail.
[0027] The flexible member 15 can comprise pushers 16 arranged at preferably regular intervals
along the extension of the flexible member 15, to push each single log L along the
feeding path PA through the cutting station 3.
[0028] In some embodiments, the forward movement of the logs can be continuous, at constant
or variable speed. In other embodiments, the forward movement can be intermittent.
During stops, the log is cut by the disc-shaped cutting blade 9. The orbital head
7 and/or the disc-shaped cutting blade 9 can have a forward and backward movement
along the path PA to cut the log L while this latter moves along the feeding path
PA without stopping, as known by those skilled in the art. In some embodiments, clamps
can be provided; they close during the cutting step to hold the log, thus ensuring
a better cut quality, and open when the log shall move forward. Preferably, two clamps
re provided: one upstream of the cutting plane, to hold the log, and one downstream
of the cutting plane, to hold the part of the log that is cut to form a roll.
[0029] During operation, the rotation of the orbital head 7 around the axis A-A transmits
a cyclic movement to the disc-shaped cutting blade 9, so that between subsequent cuts
of the log(s) L, the log(s) L can move forwards.
[0030] Figure 2 illustrates an embodiment of the cutting head 5 and, especially, of the
orbital head 7.
[0031] In this embodiment, the cutting head 5 comprises a slide 21 mounted on the orbital
head 7 so as to move according to the double arrow 21 for the purposes that will be
better described below. In some embodiments, the slide 21 is guided on guides carried
by the orbital head 7. A gear motor 25 moves the slide 21 according to the double
arrow f21. The motion can be transmitted by means of a system with a threaded bar
27 and a nut screw 29, for instance a recirculating ball screw. The nut screw 29 can
be fastened to the slide 21.
[0032] In advantageous embodiments, two grinding units, indicated with 31 and 33, can be
arranged on the slide 21. Each grinding unit 31, 33 comprises a respective grinding
wheel for grinding the disc-shaped cutting blade 9, and a controlled approach system
to move the respective grinding wheel towards the cutting edge of the disc-shaped
cutting blade, so as to move periodically the grinding wheel towards the disc-shaped
cutting blade 9. The grinding wheels of the two grinding units 31 and 33 are labelled
32 and 34 respectively. The grinding wheel 32 rotates around an axis C-C and the grinding
wheel 34 rotates around an axis D-D. The two grinding wheels 32 and 34 are so arranged
that each of them can approach one of the two sides of the cutting edge or bevel 9B
of the disc-shaped cutting blade 9, so that each of them grinds one of the two sides
of the cutting bevel 9B.
[0033] The two grinding wheels 32, 34 of the two grinding units 31, 33 can be equal to each
other, for instance when the disc-shaped cutting blade is symmetrical with respect
to its median plane, indicated with T in Figure 2. However, this is not necessary,
but only preferred in some embodiments. As known, according to some embodiments the
disc-shaped cutting blade 9 can have an asymmetrical bevel. In this case, the grinding
wheels of the two grinding units can be different from each other and/or they can
be adjusted differently from each other.
[0034] The two grinding wheels are supported in supports 36, 38 by means of shafts 40, 42.
In the embodiment described herein, the shafts 40, 42, and therefore the grinding
wheels 32, 34, are supported idle in the supports 36, 38; the rotation of the grinding
wheels 32, 34 is therefore due to the friction between the active surface of each
grinding wheel and the respective side of the cutting edge 9B on which the wheel 32,
34 acts.
[0035] Reference numbers 32A and 34A indicate the abrasive surfaces of the two grinding
wheels 32 and 34, acting on the sides of the cutting bevel or cutting edge 9B. Each
grinding wheel 32, 34 may have two opposite abrasive surfaces, and may be mounted
in two different positions, in order to allow the wheel a longer useful life, by using
the two abrasive surfaces until they are exhausted and are no longer able to grind.
[0036] Moreover, the cutting head 5 comprises a coupling for the disc-shaped cutting blade
9, indicated as a whole with number 35. The coupling 35 can comprise a mandrel or
rotary shaft 37, driven into rotation by a toothed wheel or pulley 39, around which
a toothed belt 41 can be driven, controlled by a motor 11 or other suitable motion
source, not shown in detail.
[0037] For a better understanding of the innovative aspects of the grinding system and method
described herein, reference shall be made now to Figures 3 and 4. The grinding wheel
32 is mounted on the slide 21 so that the rotation axis C-C of the grinding wheel
32 is external with respect to the disc-shaped cutting blade 9, i.e. external with
respect to the edge or bevel 9B of the disc-shaped cutting blade 9. Moreover, the
grinding wheel 32 is so mounted as to touch the respective side of the cutting edge
9B of the disc-shaped cutting blade 9 in the area Z32 (Figure 4). The area Z32 is
arranged between a plane P containing the rotation axis B-B of the disc-shaped cutting
blade and a plane P32 (Figure 4) containing the axis C-C of the grinding wheel 32
and approximately parallel to the plane P. Practically, the plane P is orthogonal
to the median plane (plane T, Figure 3) of the disc-shaped cutting blade 9.
[0038] In Figure 4, F0 indicates the resultant of the friction force generated by the contact
between the grinding wheel 32 and the disc-shaped cutting blade 9 acting on the grinding
wheel 32. The vector F0 is tangent to the cutting edge 9B in the area Z32. It can
be divided into the components F1 and F2, orthogonal to each other, wherein the component
F1 is orthogonal to the radius R of the grinding wheel 32. Therefore, the component
F1 gives the torque driving into rotation the grinding wheel 32 rotating according
to the arrow f32 when it is in contact with the disc-shaped cutting blade 9. The component
F1 of the friction force F0 is directed in the same direction as the vector representing
the tangential velocity of the grinding wheel 32. As it can be easily understood from
Figure 4, the direction of rotation of the grinding wheel 32 is therefore "entering"
the cutting edge 9B. "Entering" means that the surface 32S of the wheel in the area
Z32 moves from the edge or bevel 9B towards the axis B-B of the disc-shaped cutting
edge 9. The vectorial velocity of the grinding wheel in the area of contact with the
disc-shaped cutting blade 9 is therefore directed towards the inside of the cutting
edge. The smaller one α of the angles between the vectors representing the tangential
velocities of the disc-shaped cutting blade 9 and the grinding wheel is less than
90°.
[0039] The "entering" direction of the movement of the grinding wheel 32 with respect to
the disc-shaped cutting blade 9 in the area of reciprocal contact between the grinding
wheel 32 and the disc-shaped cutting blade 9 is optimal for the cleaning of the edge
of bevel 9B; namely, any chips or filaments are moved away from the cutting edge 9B
towards the axis of the disc-shaped cutting blade 9; in this way they do not project
from the cutting edge 9B, what would negatively affect the cutting quality.
[0040] The grinding wheel 34 is so arranged as to touch the cutting edge 9B in an area Z34.
The area Z34 is arranged in an intermediate position between the plane P defined above
and a plane P34, approximately parallel to the plane P and containing the rotation
axis D-D of the grinding wheel 34. Also in this case, F0 indicates the resultant of
the friction forces between the grinding wheel 34 and the disc-shaped cutting blade
9 acting on the grinding wheel 34. The vector F0 can be divided into components F3
and F4, wherein the vector F3 (similarly to the vector F1) transmits the rotation
torque to the grinding wheel 34 and is directed in the same direction as the vector
representing the peripheral velocity of the grinding wheel 34 in the area Z34, the
grinding wheel 34 rotating according to the arrow f34.
[0041] Therefore, similarly to what occurs for the grinding wheel 32, in the area Z34 of
contact with the disc-shaped cutting blade 9 also the grinding wheel 34 has a peripheral
velocity directed towards the inside of the cutting edge 9B; this avoids the formation
of chips or filaments that may project outside the cutting edge 9B, and more precisely
outside the joining line of the two sides defining the cutting edge 9B.
[0042] The condition described above is due to the fact that the grinding wheel 34 is arranged
with the rotation axis D-D thereof close to the rotation axis B-B of the disc-shaped
cutting blade 9. More in particular, the rotation axis D-D of the grinding wheel 34
is so arranged as to intersect the disc-shaped cutting blade 9, at a radial distance
DR with respect to the line defining the edge of the cutting chamfer 9B.
[0043] The arrangement of the grinding wheels 32, 34 described above allows, for both the
grinding wheels, such a direction of rotation that, in the contact area between the
grinding wheel 32, 34 and the disc-shaped cutting blade 9, the peripheral velocity
of the grinding wheel 32, 34 is directed towards the inside of the cutting edge, i.e.
it has a velocity component directed radially towards the rotation axis B-B of the
disc-shaped cutting blade 9, so as to have optimal grinding conditions, preventing
the formation of filaments or chips projecting outside the disc-shaped cutting blade
9.
[0044] Moreover, the grinding wheels 32, 34 are in such a position that the contact areas
Z32 and Z34 between the grinding wheels and the disc-shaped cutting blade 9 are near
each other. Namely, the two contact areas are located between the two planes P32 and
P34 (Figure 4) containing the rotation axes C-C and D-D of the two grinding wheels
32, 34. This condition is particularly advantageous as it limits bending of the disc-shaped
cutting blade 9 during grinding due to the pressure of the grinding wheels 32, 34
against the disc-shaped cutting blade 9.
[0045] Preferably, the contact areas Z32 and Z34 between each grinding wheel 32, 34 and
the disc-shaped cutting blade 9 are symmetrical with respect to the plane P, i.e.
with respect to the plane containing the rotation axis B-B of the disc-shaped cutting
blade 9 and intermediate between the rotation axes C-C and D-D of the grinding wheels
32, 34.
[0046] In Figures 1 to 4, the supports 36, 38 of the grinding wheels 32, 34 are arranged
on the same side of the plane T where there is the circular line defining the edge
of the cutting bevel 9B, i.e. the line formed by the intersection of the two sides
of the cutting edge 9B. This is particularly advantageous for accessing and replacing
the disc-shaped cutting blade 9. In other embodiments, the two supports 36, 38 may
be arranged on opposite sides of the plane T. In this case, advantages may result
from the possibility of moving the rotation axes C-C and D-D of the two grinding wheels
32, 34 closer to each other, consequently moving the areas Z32 and Z34 closer to each
other.
[0047] Moreover, in the embodiments described above, the grinding wheels 32 and 34 are mounted
idle and driven into rotation by friction between each grinding wheel 32, 34 and the
disc-shaped cutting blade 9. This is particularly advantageous as it results in the
grinding device being simple and reliable. The lack of rotation motors prevents the
grinding wheels from malfunctioning and stopping due to faults of the motors.
1. A saw machine (1) for cutting logs of web material, comprising:
a feeding path (PA) for the logs (L) to be cut;
a cutting head (5) arranged along the feeding path (PA);
a disc-shaped cutting blade (9), which is mounted on the cutting head (5), rotates
around a rotation axis (B-B) and is provided with a cyclic movement for cutting the
logs (L);
two grinding wheels (32, 34), which are arranged and configured to grind two sides
of a cutting edge (9B) of the disc-shaped cutting blade (9), and each of which rotates
around its own rotation axis (C-C; D-D); wherein the grinding wheels (32, 34) are
supported idle and driven into rotation by friction with the disc-shaped cutting blade
(9); characterized in that the grinding wheels (32, 34) are arranged with respect to the disc-shaped cutting
blade (9) such that, in a contact area (Z32, Z34) between each grinding wheel (32;
34) and the disc-shaped cutting blade (9), the grinding wheel (32; 34) has a velocity
directed towards the inside of the cutting edge; the grinding wheels (32, 34) are
arranged with respect to the disc-shaped cutting blade (9) such that the contact areas
(Z32, Z34) between the grinding wheels (32, 34) and the disc-shaped cutting blade
(9) are arranged between two planes (P32; P34), each of which contains the rotation
axis (C-C, D-D) of a respective one of the grinding wheels (32; 34); said planes are
approximately parallel to each other and to a further plane (P) containing the rotation
axis (B-B) of the disc-shaped cutting blade (9), said plane containing the rotation
axis (B-B) of the disc-shaped cutting blade (9) being arranged between the two planes
(P32, P34) containing the rotation axes (C-C; D-D) of the grinding wheels (32, 34).
2. Saw machine according to claim 1, wherein the contact areas (Z32, Z34) are symmetrical
with respect to a plane (P) substantially orthogonal to the disc-shaped cutting blade
(9) and containing the rotation axis (B-B) of the disc-shaped cutting blade (9).
3. Saw machine (1) according to claim 1 or 2, wherein, when the two grinding wheels (32,
34) are in an operative position into contact with the disc-shaped cutting blade (9),
a first (32) of said two grinding wheels (32, 34) is arranged with the rotation axis
(C-C) thereof outside the cutting edge (9B) of the disc-shaped cutting blade (9),
and the other (34) of said two grinding wheels (32, 34) is arranged with the rotation
axis (D-D) thereof inside the cutting edge (9B) so as to intersect the disc-shaped
cutting blade (9).
4. Saw machine (1) according to one or more of the previous claims, wherein said two
grinding wheels (32, 34) are supported by two respective supports (36, 38) which are
arranged on the same side of a median plane (T) of the circular blade, on which the
cutting edge (9B) of the disc-shaped cutting blade (9) is arranged.
5. A method of grinding a disc-shaped cutting blade (9) of a saw machine (1) for cutting
logs (L) of web material, the method comprising the steps of:
- placing a first grinding wheel (32) into contact with a first side of a cutting
edge (9B) of the disc-shaped cutting blade (9) in a first contact area (Z32);
- placing a second grinding wheel (34) into contact with a second side of the cutting
edge (9B) of the disc-shaped cutting blade (9) in a second contact area (Z34);
- positioning the first contact area (Z32) and the second contact area (Z34) between
a first plane (P32), containing the rotation axis (C-C) of the first grinding wheel
(32), and a second plane (P34), containing the rotation axis (D-D) of the second grinding
wheel (34), said first plane (P32) and said second plane (P34) being approximately
parallel to each other and approximately parallel to a further plane (P) containing
the rotation axis (B-B) of the disc-shaped cutting blade (9) and arranged between
the first plane (P32) and the second plane (P34);
- rotating the first grinding wheel (32) and the second grinding wheel (34) by friction
between the disc-shaped cutting blade (9) and said first grinding wheel (32) and said
second grinding wheel (34), around respective rotation axes (C-C, D-D) in such a direction
that, in each said first contact area (Z32) and second contact area (Z34), the first
grinding wheel (32) and the second grinding wheel (34) have a respective rotation
velocity directed towards the inside of the cutting edge (9B).
6. Method according to one or more of claims 5, wherein the first contact area (Z32)
and the second contact area (Z34) are symmetrical with respect to a plane (P) substantially
orthogonal to the disc-shaped cutting blade (9) and containing the rotation axis (B-B)
of the disc-shaped cutting blade (9).
7. Method according to one or more of claims 5 or 6, wherein the first grinding wheel
(32) is arranged with the rotation axis (C-C) thereof outside the cutting edge (9B)
of the disc-shaped cutting blade (9) and the second grinding wheel (34) is arranged
with the rotation axis (D-D) thereof inside the cutting edge (9B) so as to intersect
the disc-shaped cutting blade.
8. Method according to one or more of claims 5 to 7, wherein the first grinding wheel
(32) and the second grinding wheel (34) are supported by two respective supports (36,
38) which are arranged on the same side of a median plane (T) of the circular blade,
on which the cutting edge (9B) of the disc-shaped cutting blade (9) is arranged.
1. Eine Sägemaschine (1) zum Schneiden von Rollen aus Bahnmaterial, umfassend:
eine Zuführbahn (PA) für die zu schneidenden Rollen (L);
ein entlang der Zuführbahn (PA) angeordneter Schneidkopf (5) ;
ein scheibenförmiges Schneidmesser (9), das auf dem Schneidkopf (5) montiert ist,
sich um eine Drehachse (B-B) dreht und mit einer zyklischen Bewegung zum Schneiden
der Rollen (L) versehen ist;
zwei Schleifscheiben (32, 34), die so angeordnet und konfiguriert sind, dass sie zwei
Seiten einer Schneidkante (9B) des scheibenförmigen Schneidmessers (9) schleifen,
und von denen sich jede um ihre eigene Drehachse (C-C; D-D) dreht;
wobei
die Schleifscheiben (32, 34) im Leerlauf gelagert sind und durch Reibung mit dem scheibenförmigen
Schneidmesser (9) in Rotation versetzt werden;
dadurch gekennzeichnet, dass
die Schleifscheiben (32, 34) in Bezug auf das scheibenförmige Schneidmesser (9) so
angeordnet sind, dass die Schleifscheibe (32; 34), in einem Kontaktbereich (Z32, Z34)
zwischen jeder Schleifscheibe (32; 34) und dem scheibenförmigen Schneidmesser (9),
eine zur Innenseite der Schneidkante gerichtete Geschwindigkeit aufweist; die Schleifscheiben
(32, 34) in Bezug auf das scheibenförmige Schneidmesser (9) so angeordnet sind, dass
die Kontaktbereiche (Z32, Z34) zwischen den Schleifscheiben (32, 34) und dem scheibenförmigen
Schneidmesser (9) zwischen zwei Ebenen (P32,P34) angeordnet sind, von denen jede die
Drehachse (C-C, D-D) jeweils einer der Schleifscheiben (32; 34) enthält; diese Ebenen
sind annähernd parallel zueinander und zu einer weiteren, die Drehachse (B-B) des
scheibenförmigen Schneidmessers (9) enthaltenden Ebene (P), wobei diese die Drehachse
(B-B) des scheibenförmigen Schneidmessers (9) enthaltende Ebene zwischen den beiden
Schleifscheiben (32, 34) angeordnet ist, die die Drehachsen (C-C; D-D) der Ebenen
(P32, P34) enthaltenden.
2. Sägemaschine nach Anspruch 1, wobei die Kontaktbereiche (Z32, Z34) symmetrisch bezüglich
einer Ebene (P) sind, die im Wesentlichen orthogonal zu dem scheibenförmigen Schneidmesser
(9) verläuft und die Drehachse (B-B) des scheibenförmigen Schneidmessers (9) enthält.
3. Sägemaschine (1) nach Anspruch 1 oder 2, wobei, wenn die beiden Schleifscheiben (32,
34) in einer Betriebsposition in Kontakt mit dem scheibenförmigen Schneidmesser (9)
sind, eine erste (32) der beiden Schleifscheiben (32, 34) mit ihrer Drehachse (C-C)
außerhalb der Schneidkante (9B) des scheibenförmigen Schneidmessers (9) angeordnet
ist und die andere (34) der beiden Schleifscheiben (32, 34) mit ihrer Drehachse (D-D)
innerhalb der Schneidkante (9B) angeordnet ist, um das scheibenförmige Schneidmesser
(9) zu schneiden.
4. Sägemaschine (1) nach einem oder mehreren der vorstehenden Ansprüche, wobei die beiden
Schleifscheiben (32, 34) von zwei jeweiligen Trägern (36, 38) getragen werden, die
auf der gleichen Seite einer Mittelebene (T) des Kreismessers angeordnet sind, an
dem die Schneidkante (9B) des scheibenförmigen Schneidmessers (9) angeordnet ist.
5. Verfahren zum Schleifen eines scheibenförmigen Schneidmessers (9) einer Sägemaschine
(1) zum Schneiden von Rollen (L) aus Bahnmaterial, wobei das Verfahren die folgenden
Schritte umfasst:
- Platzieren einer ersten Schleifscheibe (32) in Kontakt mit einer ersten Seite einer
Schneidkante (9B) des scheibenförmigen Schneidmessers (9) in einem ersten Kontaktbereich
(Z32);
- Platzieren einer zweiten Schleifscheibe (34) in Kontakt mit einer zweiten Seite
der Schneidkante (9B) des scheibenförmigen Schneidmessers (9) in einem zweiten Kontaktbereich
(Z34);
- Positionieren des ersten Kontaktbereichs (Z32) und des zweiten Kontaktbereichs (Z34)
zwischen einer ersten Ebene (P32), die die Drehachse (C-C) des ersten Schleifscheibe
(32) enthält, und einer zweiten Ebene (P34), die die Drehachse(D-D) der zweiten Schleifscheibe
(34) enthält, wobei die erste Ebene (P32) und die zweite Ebene (P34) annähernd parallel
zueinander und annähernd parallel zu einer weiteren Ebene (P) liegen, die die Drehachse
(B-B) des scheibenförmigen Schneidmessers (9) enthält und zwischen der ersten Ebene
(P32) und der zweiten Ebene (P34) angeordnet ist;
- Drehen der ersten Schleifscheibe (32) und der zweiten Schleifscheibe (34) durch
Reibung zwischen dem scheibenförmigen Schneidmesser (9) und der ersten Schleifscheibe
(32) und der zweiten Schleifscheibe (34), und zwar um jeweilige Drehachsen (C-C, D-D)
in einer solchen Richtung, dass in jedem des ersten Kontaktbereichs (Z32) und zweiten
Kontaktbereichs (Z34), die erste Schleifscheibe (32) und die zweite Schleifscheibe
(34) eine entsprechende, zur Innenseite der Schneidkante (9B) gerichtete Drehgeschwindigkeit
besitzen.
6. Verfahren nach einem oder mehreren der Ansprüche 5, wobei der erste Kontaktbereich
(Z32) und der zweite Kontaktbereich (Z34) symmetrisch in Bezug auf eine Ebene (P)
sind, die im Wesentlichen orthogonal zu dem scheibenförmigen Schneidmesser (9) ist
und die Rotationsachse (B-B) des scheibenförmigen Schneidmessers (9) enthält.
7. Verfahren nach einem oder mehreren der Ansprüche 5 oder 6, wobei die erste Schleifscheibe
(32) mit ihrer Drehachse (C-C) außerhalb der Schneidkante (9B) des scheibenförmigen
Schneidmessers (9) angeordnet ist und die zweite Schleifscheibe (34) mit ihrer Drehachse
(D-D) innerhalb der Schneidkante (9B) angeordnet ist, um das scheibenförmige Schneidmesser
zu schneiden.
8. Verfahren nach einem oder mehreren der Ansprüche 5 bis 7, wobei die erste Schleifscheibe
(32) und die zweite Schleifscheibe (34) von zwei jeweiligen Trägern (36, 38) getragen
werden, die auf derselben Seite einer Mittelebene (T) des Kreismessers angeordnet
sind, an dem die Schneidkante (9B) des scheibenförmigen Schneidmessers (9) angeordnet
ist.
1. Une machine de sciage (1) pour couper des rouleaux de matériau en bande, comprenant
:
un chemin d'avancement (PA) pour les rouleaux (L) à couper ;
une tête de coupe (5) agencée le long du chemin d'avancement (PA) ;
une lame de coupe en forme de disque (9) qui est montée sur la tête de coupe (5),
tourne autour d'un axe de rotation (B-B) et est animée d'un mouvement cyclique pour
couper les rouleaux (L);
deux roues de meulage (32, 34) qui sont agencées et configurées pour meuler deux côtés
d'un bord de coupe (9B) de la lame de coupe en forme de disque (9), et dont chacune
tourne autour de son propre axe de rotation (C-C ; D-D) ;
dans laquelle les roues de meulage (32, 34) sont montées folles et entraînées en rotation
par friction avec la lame de coupe en forme de disque (9) ;
caractérisée en ce que les roues de meulage (32, 34) sont agencées par rapport à la lame de coupe de forme
de disque (9) de telle manière que, dans une zone de contact (Z32, Z34) entre chaque
roue de meulage (32, 34) et la lame de coupe en forme de disque (9), la roue de meulage
(32 ; 34) a une vitesse orientée vers l'intérieur du bord de coupe ; les roues de
meulage (32, 34) sont agencées par rapport à la lame de coupe en forme de disque (9)
de telle sorte que les zones de contact (Z32, Z34) entre les roues de meulage (32,
34) et la lame de coupe en forme de disque (9) soient agencées entre deux plans (P32
; P34) dont chacun contient l'axe de rotation (C-C, D-D) de l'une des roues de meulage
respective (32, 34) ; lesdits plans sont approximativement parallèles l'un à l'autre
et à un autre plan (P) contenant l'axe de rotation (B-B) de la lame de coupe en forme
de disque (9), ledit plan contenant l'axe de rotation (B-B) de la lame de coupe en
forme de disque (9) étant agencé entre les deux plans (P32, P34) contenant les axes
de rotation (C-C ; D-D) des roues de meulage (32, 34).
2. Machine de sciage selon la revendication 1, dans laquelle les zones de contact (Z32,
Z34) sont symétriques par rapport à un plan (P) sensiblement orthogonal à la lame
de coupe en forme de disque (9) et contenant l'axe de rotation (B-B) de la lame de
coupe en forme de disque (9).
3. Machine de sciage (1) selon la revendication 1 ou 2, dans laquelle, lorsque les deux
roues de meulage (32, 34) sont dans une position opérationnelle en contact avec la
lame de coupe en forme de disque (9), une première (32) desdites deux roues de meulage
(32, 34) est agencées avec son axe de rotation (C-C) à l'extérieur du bord de coupe
(9B) de la lame de coupe en forme de disque (9), et l'autre (34) desdites deux roues
de meulage (32, 34) est agencée avec son axe de rotation (D-D) à l'intérieur du bord
de coupe (9B) de manière à intersecter la lame de coupe en forme de disque (9).
4. Machine de sciage (1) selon l'une ou plusieurs des revendications précédentes, dans
laquelle lesdites deux roues de meulage (32, 34) sont supportées par deux supports
respectifs (36, 38) qui sont agencées du même côté d'un plan médian (T) de la lame
circulaire, sur lequel le bord de coupe (9B) de la lame de coupe en forme de disque
(9) est agencé.
5. Un procédé de meulage d'une lame de coupe en forme de disque (9) d'une machine de
sciage (1) pour couper des rouleaux (L) de matériau en bande, le procédé comprenant
les étapes consistant à :
- mettre une première roue de meulage (32) en contact avec un premier côté d'un bord
de coupe (9B) de la lame de coupe en forme de disque (9) dans une première zone de
contact (Z32) ;
- mettre une seconde roue de meulage (34) en contact avec un second côté du bord de
coupe (9B) de la lame de coupe en forme de disque (9) dans une seconde zone de contact
(Z34) ;
- positionner la première zone de contact (Z32) et la seconde zone de contact (Z34)
entre un premier plan (P32) contenant l'axe de rotation (C-C) de la première toue
de meulage (32), et un second plan (P34) contenant l'axe de rotation (D-D) de la seconde
roue de meulage (34), ledit premier plan (P32) et ledit second plan (P34) étant approximativement
parallèles l'un à l'autre et approximativement parallèles à un autre plan (P) contenant
l'axe de rotation (B-B) de la lame de coupe en forme de disque (9) et agencé entre
le premier plan (P32) et le second plan (P34) ;
- faire tourner la première roue de meulage (32) et la seconde roue de meulage (34)
en friction entre la lame de coupe en forme de disque (9) et ladite première roue
de meulage (32) et ladite seconde roue de meulage (34), autour d'axes de rotation
respectifs (C-C, D-D) dans un sens tel que, dans chacune des première zone de contact
(Z32) et seconde zone de contact (Z34), la première roue de meulage (32) et la seconde
roue de meulage (34) ont une vitesse de rotation respective orientée vers l'intérieur
du bord de coupe (9B).
6. Procédé selon l'une ou plusieurs des revendications 5, dans lequel la première zone
de contact (Z32) et la seconde zone de contact (Z34) sont symétriques par rapport
à un plan (P) sensiblement orthogonal à la lame de coupe en forme de disque (9) et
contenant l'axe de rotation (B-B) de la lame de coupe en forme de disque (9).
7. Procédé selon l'une ou plusieurs des revendications 5 à 6, dans lequel la première
roue de meulage (32) est agencée avec son axe de rotation (C-C) à l'extérieur du bord
de coupe (9B) de la lame de coupe en forme de disque (9) et la seconde roue de meulage
(34) est agencée avec son axe de rotation (D-D) à l'intérieur du bord de coupe (9B)
de manière à intersecter la lame de coupe en forme de disque.
8. Procédé selon l'une ou plusieurs des revendications 5 à 7, dans lequel la première
roue de meulage (32) et la seconde roue de meulage (34) sont supportées par deux supports
respectifs (36, 38) qui sont agencés du même côté d'un plan médian (T) de la lame
circulaire, sur lequel le bord de coupe (9B) de la lame de coupe en forme de disque
(9) est agencé.