Note: Descriptions are shown in the official language in which they were submitted.
208~g~
BACKGROUND OF THE INVENTION
The most wldespread cutting machines for the formation of
small rolls of paper - of the type including toilet paper, all-
purpose wipers and other ~ are provided with a discoidal, high-
speed rotating blade. The axis of rotation of the blade is in
turn provided with a motion which may be either a reciprocating
motion in a direction perpendicular to the log feeding motion, or
it may rotate about an axis parallel to the log feeding motion.
Whatever the type of the blade axis motion, it has the purpose of
moving the blade in and out of the product to be cut, so that
when the blade is clear of the product to be cut, the latter is
able to advance to an extent corresponding to the desired length
to which the small roll is to be cut. The frequency of the
cyclic movements of both the cutting element and the product
feeding systems, which is equal to the production rate of the
small rolls, gives rise to obvious qualitative and quantitative
drawbacks and limitations in the production.
DESCRIPTION OF THE INVENTION
These and other drawbacks are overcome by the cutting
machine of the present invention, which is provided for cutting
small rolls of toilet-paper or the like from rolls or logs of
considerable length, said machine comprising sliding seats or
carriers and means for feeding one or more logs to be cut, and a
rotor with a blade. More specifically, according to the
2~88~8~.
invention, the blade has a helicoidal conical shape with external
cutting edge having radii which change over a portion of a
revolution (or even a complete revolution). The difference
between the maximum and minimum radii of the cutting edge is at
least equal to the maximum diameter of the rolls or logs to be
cut. The rotating shaft and the blade rotor are not displaced
during the rotor's revolution, and are slightly inclined with
respect to the direction of sliding of the iogs in their seats or
carriers. Thus the cut performed on the logs by the cutting edge
of the cutting blade will, on the average, be perpendicular to
the axes of the logs. The advancement of the log(s) (B) in the
carriers is continuous and the cutting takes place during a
portion of a revolution of the rotor and during that portion of
the log's advancement which corresponds to the axial length of
the small rolls to be produced.
The blade sharpening means may comprise a cyclically movable
unit (i.e. movable upon every revolution of the blade rotor)
which moves both radially and axially with respect to said blade.
The system for the advancement of the grinding wheels towards the
blade may be obtained in two different ways: either moving the
carriage of the grinding wheels towards the rotor axis, or moving
the blade within its seat towards the grinding wheels.
The present cutting machine includes (similarly to the
traditional cutting machines) two-part clamps which grip the logs
, -~ 208~g8.1
and which are located both upstream and downstream of the cutting
area. Said clamps elastically exert a constant, adjustable and
not necessarily high pressure onto the material of each log in
order to cause a continuous forward advancement of the log. The
clamps, in this case, are only intended to grip the roll or log
during the cutting action so as to counteract the transverse
thrust caused by the blade.
Owing to the successive sharpenings, the blade dimensions
are reduced. To compensate for this wear and to ensure the
complete cutting of rolls or logs, the machine is provided with a
system allowing the blade and rotor axis to move close to the
sliding cradles of the rolls or logs.
With the above and other objects in view, more information
and a better understanding of the present invention may be
achieved by reference to the following detailed description.
2~888~
DETAILED DESCRIPTION
For the purpose of illustrating the invention, there is
shown in the accompanying drawings a form thereof which is at
present preferred, although it is to be understood that the
several instrumentalities of which the invention consists can be
variously arranged and organized and that the invention is not
limited to the precise arrangements and organizations of the
instrumentalities as herein shown and described.
In the drawings, wherein like reference characters indicate
like parts:
FIG. 1 shows a schematic plan view.
FIG. 2 shows a schematic front view on line II-II of Fig. 1.
FIG. 3 shows a partial side view on line III-III of Fig. 1.
FIGS. 4 and 5 show two partial and enlarged views of Fig. 1
and Flg. 2.
FIG. 6 shows a sectional partial view of the blade rotor.
FIGS. 7, 8 and 9 show in side and front views a set of
"clamps" to support the rolls or logs in the cutting region.
FIG. 10 shows a first embodiment of the system for periodic
sharpening of the blade.
FIG. 11 is a schematic view on line XI-XI of Fig. lO.
FIGS. 12, 13, 14 and 15 show enlarged details of parts of
the assembly of Fig. 10.
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FIG. 16 diagrammatically shows the comparison between the
first and the second embodiment of the sharpening system.
FIGS. 17 and 18 schematically show an axial view and a side
view of the machine with the second embodiment of the sharpening
system; and
FIG. 19 shows an exemplary section view according to
portions of planes perpendicular to that of Fig. 17.
~ Referring now to Figs. 1 to 6, numeral 1 indicates the
cutting area of a log-saw with a structure (3) attached thereto
for holding the cradles or seats which slidingly carry the logs
to be cut. The cradles in this case are three, designated 4, 4A
and 4C, but there may be more or less, as desired. Acting along
said seats are chain pushers or any other type of pushers
provided with a continuous flexible member, which include thrust
elements (5) engaged along chains (7) driven between chain wheels
(9) and (11) (or pulleys for a toothed chain) so as to cause the
pushers (5) to slide along cradles such as those indicated by
(4), (4A), (4C).
Mounted on the housing (with ball bearings, not shown) is a
sleeve (14) whose axis is slightly inclined with respect to the
roll feeding direction defined by the sliding cradles. This
sleeve lies in a plane which is parallel to the plane in which
the two other sliding cradles (4 and 4C) lie. Cradles (4) and
(4C) are arranged slightly higher than the sliding cradle (4A).
2~3~8 L
Supported within sleeve (14) is a main shaft (15). Mounted on
the sleeve (14) are: 1) a unit (16) which is able to oscillate
about the axis of the sleeve (14) and which carries the cutting
tool to be described hereinafter; 2) a motor (18); and 3) the
complete blade-sharpening group to be described later on. A belt
drive (20) connects the motor (18) to the shaft (15). A belt
drive (22), arranged outside the housing (1), transmits the
motion of the shaft (15) to a reduction gear (24). The latter
transmits, via a universal joint (26), a reduced but continuous
motion, (derived from the motor (18) as above described) to a
shaft (28) on which the chain pulleys or wheels (11) are mounted
for moving the pushers (5).
The unit (16), oscillating around the common axis of sleeve
(14) and shaft (15), is supported (on the side opposite the
sleeve 14) by a rod (30) which is pivoted at (32) to the unit
(16) and at (34) to a bracket (36) fixed to the main frame (1).
Said rod (30) can be moved up and down by a screw-and-nut system
operated by a motor-reducer (38) suitably calibrated for
determining the angular displacement of the unit (16) to
accommodate the extent of wear of the cutting blade, to be
described later. This adjustment to the unit (16) (as a
consequence of the action of the sharpening means to be
described) ensures the sharpening of the cutting blade because
2~8~ L
the parts (30) to (38) control the slow, progressive lowering of
the unit (16) around the axis of sleeve (14) and shaft (15).
A belt (40) connected to shaft (15) turns a rotor (42) whose
hub (44) and extension (45) rotate about an axis concentric to
that of shaft (15). It is carried by the unit (16) in a position
between the pivot-point on the sleeve (14) and the pivot-point
(32) of the rod (30). Attached to the flange of the hub (44) is
a disk (46) at the periphery of which an annular ring (48) is
engaged having a particular shape with a flange-like shoulder
(48A) of helicoidal development. A flexible blade (50) is
securely mounted against said flange-like shoulder (48A) and said
blade (50) extends over a partial arc of the periphery of the
flange-like shoulder (48A) (over an angular development of 180
degrees in the illustrated embodiment). A corresponding ring
sector fixing ring (48B) cooperates with said blade (50) by
tightening screws on the shoulder (48A). The blade (50) has an
external cutting edge (50A) having a development with an almost
linearly changing radius from a minimum to a maximum value
between the two ends (50B) and (50C) of the blade. The blade
(flat before mounting) assumes the helicoidal shape when it is
clamped between the flange-like shoulder (48A) and the fixing
ring (48B). The difference D (see Fig. 6) between the maximum
radius and the minimum radius of the cutting edge (50A)
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corresponds to the maximum dimension of the diameter of the logs
(B) to be cut by the cutting machine.
The end ~50C) of maximum radius of blade (50) moves along a
circular trajectory T. The trajectory T, in the lower stretch
thereof, passes below the sections of the logs B which are in the
cradles (4, 4A, 4C). The inclination of the axis of the rotor
(42) (which is parallel to the axis of sleeve (14) and shaft
(15)) is such that the chord of the blade helix, within the arc
where it engages the logs B to be cut, is substantially
perpendicular to the axes of the logs, i.e., to the axes of the
cradles in which the logs are sliding. The geometrical condition
mentioned above is approximate, but it does provi`de acceptable
tolerances and sufficient accuracy for the cutting plane to be
substantially perpendicular to the axes of the logs to be cut.
The direction of rotation of the rotor being that indicated
by the arrow F, during each turn the external cutting edge (50A)
of the blade (50) is active for about half a revolution, that is
to say, for an arc which has an angular development corresponding
to the cutting edge of the blade itself. Said cutting edge (50A)
moves progressively down from the position of maximum distance
from cradles (4, 4A, 4C) (which is that of the leading edge (50B)
of the blade) until it passes beyond the bottom of the cradle
(4), in the region of maximum radial dimension of the blade,
i.e., in the terminal edge (50C) of said blade. During the
2 ~
fraction of revolution (in this case about a half turn) of the
rotor, during which the blade (50) is cutting the logs, the said
blade, because o~ its helical development, is displaced in the
log-feeding direction, according to arrow fB (see Fig. 3). This
displacement is equal to the fraction of pitch (generally about
half a pitch) of the geometrical helix within which the cutting
edge lies and, practically, of the helicoid within which the
blade (50) lies.
The full pitch of the geometrical helix defined by the
cutting edge (50A) corresponds to the axial dimension of the
small rolls which are obtained by cutting the logs B by means of
the blade. During the active arc of the blade (slightly larger
than 180 degrees in the drawing), the blade carries out the
cutting of the logs in the three cradles (4, 4A, 4C) by advancing
along with the logs which are pushed by the pushers (5). After
having completed the active arc of the blade (50A), that is to
say, after the blade end (SOC) has come out of contact with the
logs, said rolls or logs continue to move forward along the
cradles, so that there are obtained the small rolls cut by the
blade (50) which have an axial dimension which is equal to the
pitch of the geometrical helix of the cutting edge (50A) and
which is, in part, operated during the cutting by the blade (50)
and, in part, (for slightly less than 180 degrees of the rotation
of rotor (42) ) while the blade is inoperative.
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It will be appreciated that with the system described above
there is provided continuous rotation of the rotor (42) of blade
(50), as well as continuous advancement of logs B within the
cradles (4) by means of the pushers (5). None of the members so
far described has an alternate motion with a frequency equal to
the rotation frequency of the blade. Some members (to be
described later) which have relatively very limited masses are
provided with a limited reciprocating motion with a frequency
which corresponds to that of rotation of rotor (42). These
members are, in particular, some of the members of the device for
sharpening the blade (50), which device has to follow the cyclic
variations of the radial dimension of the blade and of the
helicoidal development of the cutting edge (50A). The
progressive displacement carried out by the components (30)
(38), to move the axis of rotation of the rotor (42)
progressively closer to the cradles (4), according to the blade
wear, is an extremely slow, progressive and not reciprocating
motion. As will be evident to those skilled in the art, the
described arrangement allows obvious advantages in comparison
with the traditional cutting machines having relatively high
masses provided with reciprocating motion at the frequency of the
cutting cycles.
According to an alternate embodiment, a system of cyclic
variation of the advancement speed of th~ rolls during each
2~8~8:;~
revolution of the rotor (42) may be provided for increasing or
decreasing the advancing speed during the step in which the blade
(50) is inoperative. This may be achieved through a device shown
in Fig. 2 by the dotted line (200) near the universal joint (26)
on the transmission (15) to (28). Such device may be similar to
that described in U.S. Patent Application Ser. No. 07/856,449, or
in the corresponding E.P. Application No. 92830161.3, the
contents of which are incorporated herein. The axial dimension
of the small rolls is increased by an acceleration and decreased
by a deceleration.
As already noted, the logs within cradles (4, 4A, 4C) move
forward with continuous motion (and possibly with cyclic
variations). At the cutting area where the blade (50) works,
there is the need of a lateral, i.e., a peripherical support for
the log, in order to support the material during the cutting
operation. This is usually provided for by so-called "clamps"
which, in the prior art machines, cyclically cause a temporary
pressure on the log when the log is stopped to carry out the cut,
and which are released to allow for the intermittent advancement
of the log. In the cutting machine according to the present
invention, wherein the logs continue to move during the cutting
operation, pressers are provided which act continuously to
provide lateral restraint, but which allow sliding of the logs
because there is very little friction between the external
2~8~8:i
surface of the log and the concave surface of the active parts of
the pressers. According to what is shown in Figs. 3, 7 and 8,
along each cradle (4, 4A, 4C) two elements (54) and (56) are
provided whose concave surface is turned towards arrow F which
indicates the movement of blade (50). Accordingly, the log,
which is urged in the direction of arrow F by the blade during
cutting, steadily abuts against the concave surfaces of said
elements (54) and (56). Further elements (54A) and (56A),
substantially facing those indicated by (54) and (56) and
symmetrically disposed with respect to the axis of the log
cradles, are resiliently biased so as to exert a relatively
limited and adjustable pressure on the advancing logs thereby
allowing the continuous advancement of the material. It is thus
possible to keep the material sufficiently supported in the
cutting area and to provide a "clean" cut on a material which is
sufficiently sustained and properly supported as described. The
elements 54A and 56A are supported by rocker members (58) which
are substantially T-shaped and articulated at (60) to fixed
points of the housing 1, and further articulated at (62) to a bar
(64) which is pushed in the direction of arrow F64 by a spring
or, preferably, by a pneumatic cylinder-piston spring (66) which
reacts on a stem (68) engaged at (70) to the fixed structure of
frame 1. This arrangement, as well as a variation of the
pneumatic pressure, makes it possible to adjust the resilient
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thrust of the movable elements (54A~ and (56A) in order to
control the switch pressure on the logs to allow for their
continuous sliding. This arrangement of resilient yielding
elements (54A) and (56A) allows also to match variations in the
diameter of the logs fed to the cutting machine, at least within
certain limits of tolerance. The elements (54, 56, 54A, 56A)
have flared or "funnel"-shaped edges facing the incoming
material, and have rear ends tapered or shaped to accommodate the
blade during the cutting.
A system will now be described which ensures at all times a
proper sharpening of the cutting edge (50A) of blade (50).
The sharpening system must be provided with cyclic radial
motion which accommodates the variations of the radius of the
cutting edge (50A), and with a cyclic axial motion which follows
the helicoidal shape of the cutting edge (50A). Each of these
two cyclic motions, which are synchronous, must be carried out
during each revolution of the rotor (42). Each revolution must
have an active phase while the cutting edge (50A) slides in front
of the sharpening system, and a return phase synchronized with
the arc without cutting edge. The sharpening system must adjust
progressively during the life of the blade, to compensate for the
wear of the blade and maintain the sharpening thereof.
As shown in particular in Figs. 5 and 10 to 15, a support
(74) is fixed on the unit 16 which oscillates on the sleeve (14).
14
2~88~8 ~
Two guides (80) are fixed on the extension (74A) of said support
by means of blocks (76), (78), the guides lying in a radial plane
passing through the axis of rotor (42) and shaft (45). Said
guides (80) also lie in a plane inclined with respect to a plane
perpendicular to the axis of rotation of the rotor (42). This
inclination actually corresponds to the inclination of the
straight line LR (see Fig. 10) grazing the ends (50B) and (50C)
of blade (50) when these ends are in their closest position to
guides (80).
Mounted on the support (74), and in particular on bracket
(74B) (see Fig. 4) is a pin (82), the axis of which is parallel
to that of shaft (45) and on which a lever arm (84) can
oscillate. A dual tappet roller (86) is fastened to said arm
(84), and it has two coaxial rollers which operate between the
two flanks of a channel cam (88), the two flanks of different
height of said channel (88) (see Figs. 3 and 4). The channel
(88) is formed in a discoidal body (90) which is fixed to the
blade rotor (42). The channel cam (88) is annularly developed so
that, with the rotation of the rotor (42) of blade (50), the
lever arm (84) may oscillate under the control of the channel cam
(88). The movable end of the lever arm (84) engages, through a
ball-joint articulation generally shown at (92), a tie-strut rod
(94) having the function indicated below. Slidingly mounted on
the guides (80) is a slide (96) which may be driven into
2~8~
reciprocating motion along the guides (80) by the tie-strut rod
(94) which, at the end opposite the ball-joint (92) is another
ball-joint (98) connected to the slide (96). The ball joints
(92), (98) allow the reciprocating operation of the slide (96) by
means of the lever arm (84) even though the guides (80) are
inclined as set forth above.
The slide (96) supports, throgh an extension (96A), two
parallel guides (100), (102). The guide (100) is cylindrical and
fixed, while the guide (102) is a guide-shaft able to rotate
within ball bearings (104), but not move axial displacements, and
is provided with a threaded section (102A). Sliding on guides
(100) and (102) is a skid (106) which is capable of movement
along the guides (100) and (102) in a direction which is kept
substantially at right angle to the axis of rotor (42) and shaft
(45). The skid (106) carries, in the manner indicated
hereinafter, the grinding wheels for sharpening the blade (50).
Said skid (106), which, along with the grinding wheels is
coordinated with the reciprocating motion of slide (96), must be
progressively and slowly moved closer to the rotor to accommodate
the progressive wear of the blade (50), to ensure the correct
sharpening of the cutting edge (50A) of the blade. The slide
(96) is driven at a frequency corresponding to that of rotation
of the rotor (42), with reciprocating displacements LR (see Figs.
lG and 13) along the guides (80) in order to follow, during each
16
-
20~82~ ~i
revolution, the radial and axial variation of the shape of the
cutting edge (50A) of blade (50). Simultaneously, the grinding
wheels, which are carried by the skid (106), must be
progressively and slowly displaced with respect to the slide (96)
to the extent necessary to compensate for the progressive wear of
blade (50). Said progressive advancement of the skid (106) is
determined by the screw-like coupling of the threaded part (102A)
of cyclindrical shaft-like guide (102) with a corresponding nut
(106A) of skid (106~, and by the rotation of said guide (102).
Mounted on this rotating cylindrical and threaded shaft-like
guide (102), is a unidirectlonal (free-wheel) connection between
said shaft and a rocker lever (110) oscillating with
reciprocating motion about the axis of said guide shaft (102).
The rocker lever (110) is moved with reciprocating oscillation
movements about the axis of the guide-shaft (102) by a
preferably pneumatic cylinder-piston system (112), and
with a frequency depending on the extent of the blade
wear. This ensures, by a positive control in the two
directions or by an elastic reaction control, the periodic
oscillation over limited arcs of the rocker lever (110). The
latter forms, together with a central member (113) carried by the
guide-shaft (102), a free wheel system which includes a
unidirectional elastic driving member (llOA). This
unidirectional coupling system (110), (llOA), (113), makes it
2~3~8:~
possible to achieve a slow, intermittent rotation of the guide-
shaft (102) and thereby a slow advancement of the skid (106) in
the direction of arrow (F106) during a life cycle of a blade, and
the return of same skid back to the starting position (spaced
from the cutting edge of the blade) upon the replacement of the
worn out blade with a new one.
The skid (106) carries a pin (116) protruding from opposite
sides of said skid, to support two grinding wheel-holder units
(118), (120) which are cantilever-developed and capable of being
adjusted in angular position on the pin (116). Their relative
angular position may be observed through respective index systems
(118A), (120A), which cooperate with relevant angular scales
(106A), (106B) borne by the skid (106).
On the grinding wheels-holder unit (118) and, in particular,
on its cantilever projecting parts, there are two leaf springs
(122) connected to a grinding wheel support (124). A cylinder-
piston system (126) ~see Fig. 12) operates between the grinding
wheel-holder unit (118) and the grinding wheel support (124),
thereby causing said grinding wheel support (124) to move
parallel to itself, owing to the flexibility of the leaf springs
(122). This grinding wheel support (124) carries a motor (127)
whose projecting shaft drives the grinding wheel (128), the
grinding wheel having an inclination depending on the angular
18
2 ~ 8 ~
setting of the grinding wheels-holder unit (118) on the shaft
(116), said setting being controlled by the index (118A).
Another grinding wheel-holder unit (120) (which is oriented
at an angle opposite to the members supported by the grinding
wheels-holder unit (118) ) is similar to the grinding wheels-
holder unit (118) described above, with leaf springs (132) which
carry a grinding wheel support (134) designed to be controlled by
a cylinder-piston system (136). Said grinding wheel support
(134) is provided with a motor (13/) of its own, which drives the
relevant grinding wheel (138), the latter being offset with
respect to the one indicated by (128) and inclined in opposite
direction thereto, wtih respect to the plane of the blade (50) to
be sharpened.
The arrangement of the skid (106) and all that is connected
thereto, makes it possible accurately to position the grinding
wheels (128) and (138) at a given inclination, and to resiliently
urge them by means of the leaf springs (122) and (132) and of the
cylinder-piston systems (126) and (136) against the cutting edge
(50A) of blade (50). This causes the grinding wheels to follow
the cyclic variation of the radius of the cutting edge (50A) of
blade (50) by virtue of the reciprocating motion of slide (96) at
every revolution of rotor (42). It also causes the grinding
wheels to move forward in a substantially radial direction shown
by arrow F106 according to the blade wear with an intermittent
2~38~
feeding rate as determined by the cylinder-piston system (112)
which rotates the guide-shaft (102), and thus causes the slow
advancement through the screw coupling of the skid (106). The
replacement of the blade is accompanied by a fast return of the
wear-compensating system to the original position. The grinding
wheèls follow the blade as they are operated in a reciprocating
fashion owing to the alternate motion of the slide (96) along the
guides (80) and owing to the inclination of such guides (80),
which makes it possible to follow the helicoidal shape of the
blade as well as the radial variation of the blade during each
revolution.
Shown in Figures 16 to 19 is a second and different
embodiment of the sharpening system. In the embodiment shown in
Figs. 10 to 14, the grinding wheels (128) and (138) are carried
by the skid (106) which is progressively and radially brought
close to the axis of rotor (42), by means of the guides (100) and
(102) and of drive (110), (112), (113) acting on the gulde (102)
which is threaded at (102A), to cause the skid to advance in the
direction of arrow (F106). According to the embodiment shown in
Figs. 16 to 19, a relative angular or "tangential" advancement of
a blade (350) (corresponding to blade (50) ) is imposed with
respect to the cam (corresponding to cam (88) ) which operates
the reciprocating motion of the slide (96). In practice, by
considering the diagrams of Fig. 16, which shows the linear
2~8~8~
development of the arcuated blades in the diagram A
(corresponding to the solution of Figs. 10 to 14), provision is
made for the grinding wheels (128), (138) to perform, not only
the reciprocating motion caused by slide (96), but also the
advancement according to arrow F106 with respect to the blade
(50). In the diagram B, the grinding wheels (428), (438) do not
advance gradually, and correspond only to the reciprocating
motion of the slide (396) along the guides (80). It is the blade
(350) which moves forward gradually in the direction of arrow
F406 with an angular movement relative to rotor (42) to which the
channel cam (88) is fixed.
In the Figs. 17 to 19, the members corresponding to those
already described are designated by the same reference numbers
increased by "300". The members (348), (348B) which engage the
blade (350), are part of a discoidal core which also includes a
centrally bored disk (246). The inner edge (246A) of the disk
(246) is slidingly engaged within a channel (250) formed between
the discoidal body (90) of the channel cam (88), the hub (344)
and a side member (252) fixed like the body (90) to the periphery
of the hub (344). In this way, the unit (246), (348), (348B) may
be angularly displaced within the channel (250) with respect to
the cam (88) which drives the slide (396) into a reciprocating
motion. Rotatively mounted on the hub (344) is a bush (211)
which is movable about its axis which is parallel to, but offset
2~88~8~
from, the axis of rotor (42). Threadedly engaged within a
diametrally extending threaded hole (213) of bush (211) is a
threaded rod (215). This rod (215) is rotatively connected
through an articulated joint (217) to a shaft (219) mounted
through roll bearings on a support (221) which is carried by unit
(246), (348), (348B) of blade (350). A device (223) is able to
drive into a slow and intermittent rotation the shaft (219) and
thus the threaded rod (215). This device (223) is not described
in dëtail as it can be constructed exactly like the device (110),
(112), (113), (llOA) which drives the guide-shaft (102), (102A)
in ~he same way as described in the previous embodiment. A duct
for compressed air will be arranged to include a joint rotating,
for example, inside the axial hole of the rotor (42) and its
shaft, to lead into the pneumatic actuator of device (223). The
threaded rod (215), therefore, causes a gradual angular sliding
of the group (348), (348B), (246), (246A) of blade (350) with
respect to hub (344) and cam (90), (88), thereby determining an
angular movement of the cutting edge (350A) of blade (350) in the
direction of arrow F406 with respect to the sharpening wheels.
In this second embodiment, the following members are omitted
from slide (96): actuator device (112), (110), (113), (llOA);
guide-shafts (100) and (102), (102A) and skid (106). As can be
seen in Fig. 17, the same slide (396) carries the pin (416) for
the two grinding wheels-holder units (418) and (420). Moreover,
. ~ ~
2 ~ 81
in this second embodiment, there is no longer need to
progressively move the axis of rotor (42), (344) close to the
roll or log cradles (4), (4A), (4C) and to the clamps, since the
cutting edge (350A) of the blade (350) does not change its
distance from the axis of rotation due to wear and sharpenings,
but it actually changes only to a little extent its own angular
position. The variations take place according to arrow F406 (see
Fig. 16B) (i.e. tangentially) and not according to arrow F106
(i.e. radially) (see Fig. 16A) as in the first solution of the
sharpening device. Accordingly, the arm (16) needs no longer to
be moved about the axis of shaft (15) and sleeve (14), and the
related members (32), (30), (34), (38), (36) are not required.
The arm (16) can be replaced with a lever (116) of a portal-like
structure, a column 116A of which replaces the adjustable support
(32), (30), (34), (38), (36).
It is understood that the drawing shows an exemplification
given only as a practical demonstration of the invention, as this
may vary in the forms and dispositions without nevertheless
coming out from the scope of the idea on which the same invention
is based. The possible presence of reference numbers in the
appended claims has the purpose to facilitate the reading of the
claims, reference being made to the description and the drawing,
and does not limit the scope of the protection represented by the
claims.
