CROSS-REFERENCE TO RELATED APPLICATIONS
TECHNICAL FIELD
[0002] The invention relates to a sanding machine for sanding/finishing/brushing components
made of wood, metal or the like.
[0003] The invention especially finds advantageous application in the sanding/finishing
of bevelled edges of bars with an elongated shape used as beams or columns in the
building industry, to which explicit reference will be made in the description below
without because of this loosing in generality.
PRIOR ART
[0004] When dealing with the sanding/finishing of bevelled edges for bars for the building
industry, a sanding machine is known, which comprises at least one sanding unit to
sand/finish the bars; and a feeding device, which defines a support surface for at
least one bar and is designed to move the bar in a horizontal direction parallel to
the support surface and along a path extending through the sanding unit.
[0005] Generally speaking, the sanding unit comprises a frame, at least two pulleys (normally,
three pulleys) mounted so as to rotate around respective longitudinal axes and an
abrasive belt wound in a ring shape around the pulleys.
[0006] The sanding unit further comprises at least one pushing element, which is arranged
between the pulleys and is movable between an operating position, in which it pushes
the abrasive belt against the bevelled edges of the bar, and a rest position, in which
it disengages the abrasive belt from the bar.
[0007] Since the bevelled edges of the bar have a relatively small width, in order to ensure
a relatively even and uniform wear of the abrasive belt, the sanding unit is further
provided with an operating device to move one of the pulleys with an oscillatory reciprocating
motion around a rotation axis, which is transverse to the relative longitudinal axis.
[0008] The oscillatory reciprocating motion of the pulley generates a straight reciprocating
motion of the abrasive belt along the pulleys parallel to the relative longitudinal
axes.
[0009] The operating device normally comprises an actuator cylinder, which is provided with
an output rod connected to the pulley and alternatively movable between an extracted
position and a retracted position, and a photodetector, which is designed to selectively
control the operation of the actuator cylinder.
[0010] In use, the actuator cylinder is activated in order to move the output rod from the
retracted position to the extracted position, when the photodetector detects the passage
of the abrasive belt, and is activated in order to move the output rod again from
the extracted position to the retracted position after a constant amount of time.
[0011] Since the movement of the abrasive belt along the pulleys depends on the speed of
movement of the abrasive belt around the pulleys, known sanding machines of the type
described above suffer from some drawbacks, which are mainly due to the fact that
the straight reciprocating motion of the abrasive belt is reversed, in one case, when
the photodetector detects the passage of the abrasive belt and, in the other case,
after the constant amount of time mentioned above has elapsed.
[0012] As a consequence:
when the moving speed of the abrasive belt and, hence, the movement of the abrasive
belt along the pulleys are relatively small, the abrasive belt wears in the area of
a relatively small portion of its; and
when the moving speed of the abrasive belt and, hence, the movement of the abrasive
belt along the pulleys are relatively great, the abrasive belt wears in the area of
a relatively large portion of its.
SUBJECT-MATTER OF THE INVENTION
[0013] The object of the invention is to provide a sanding machine for sanding/finishing/brushing
components made of wood, metal or the like, which does not suffer from the drawbacks
described above and is simple and economic to be manufactured.
[0014] According to the invention, there is provided a sanding machine for sanding/finishing/brushing
components made of wood, metal or the like according to the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The invention will now be described with reference to the accompanying drawings showing
a non-limiting embodiment thereof, wherein:
figures 1a and 1b are two schematic plan views, with parts removed for greater clarity,
of a preferred embodiment of the sanding machine of the invention, which is shown
in two different operating positions;
figures 2, 3 and 4 are three schematic perspective view, with parts on a larger scale
and parts removed for greater clarity, of a detail of the sanding machine of figures
1a and 1b;
figure 5 is a schematic side view, with parts removed for greater clarity, of the
detail of figures 2, 3 and 4;
figure 6 is a schematic perspective view, with parts removed for greater clarity,
of a first detail of figures 2, 3 and 4;
figure 7 is a schematic plan view, with parts removed for greater clarity, of a second
detail of figures 2, 3 and 4;
figures 8 and 9 are two schematic perspective views, with parts removed for greater
clarity, of a third detail of figures 2, 3 and 4;
figures 10 and 11 are two schematic perspective views, with parts on a larger scale
and parts removed for greater clarity, of a variant of the detail of figures 2, 3
and 4;
figures 12 and 13 are two schematic perspective views, with parts removed for greater
clarity, of a detail of figures 10 and 11;
figure 14 is a schematic perspective view, with parts removed for greater clarity,
of a detail of figures 12 and 13; and
figure 15 is a schematic perspective view, with parts removed for greater clarity,
of a detail of figure 14.
PREFERRED EMBODIMENT OF THE INVENTION
[0016] With reference to figures 1, 2, 3, 4 and 5, number 1 indicates, as a whole, a sanding
machine for sanding/finishing/brushing components 2 made of wood, metal or the like,
especially beams or columns for the building industry.
[0017] Each component 2 has an elongated shape and is delimited by an upper face 3 and by
a lower face 4, which are substantially parallel to one another, by two end faces
5, which are substantially parallel to one another and perpendicular to the faces
3, and by two side faces 6, which are parallel to one another and perpendicular to
the faces 3.
[0018] The sanding machine 1 comprises a roller conveyor device 7, which extends in a horizontal
direction 8 and comprises, in turn, a plurality of motor-driven transport rollers
9, which define a support surface A for the components 2 and are mounted so as to
rotate around respective rotates axes 10, which are parallel to one another and to
a horizontal direction 11, which is transverse to the direction 8.
[0019] The components 2 are moved by the device 7 along a path P extending through a plurality
of operating units, especially two operating units 12, 13, which are mounted between
the rollers 9 and are each designed to process a relative face 6.
[0020] The sanding machine 1 is provided with a limit stop device 14, which is arranged
upstream of the unit 12, extends in the direction 8 and allows the components 2 to
be correctly positioned in the direction 11.
[0021] The unit 12 comprises an elongated frame 15, which extends in the direction 11 and
supports an intermediate slide 16, which extends in the direction 11 and is coupled
to the frame 15 in a sliding manner through the interposition of a shock absorber
device 17 (figure 6) so as to make, relative to the frame 15, straight movements in
the direction 11.
[0022] The device 17 comprises, in particular, a pneumatic cylinder 18, which is fixed to
the frame 15 parallel to the direction 11, a pneumatic cylinder 19, which is fixed
to the slide 16 parallel to the direction 11 and faces the cylinder 18, and an output
rod 20, which is coupled to the cylinders 18, 19 in a sliding manner.
[0023] The slide 16 supports two conveyor assemblies 21, 22, which are arranged on opposite
sides of the path P in the direction 11 and define a feeding channel 23 feeding the
components 2 through the unit 12.
[0024] The assembly 21 is arranged on the side of the path P opposite the one of the device
14 and comprises a horizontal slide 24 with a substantially rectangular shape, which
is mounted on the slide 16 is coupled to the slide 16 in a sliding manner and is further
coupled, by means of a screw-nut screw coupling, to a screw 25 of a relative operating
device 26 (figure 7), a motor 27 thereof causing the rotation of the screw 25 in order
to cause the slide 24 to make straight movements along the slide 16 in the direction
11.
[0025] The device 26 further comprises a nut screw 28, which is coupled to the screw 25
and is engaged by the slide 24 in a sliding manner through the interposition of a
shock absorber device 29 (figure 7) comprising two pneumatic cylinders 30, which are
mounted between the slide 24 and the nut screw 28 parallel to the direction 11.
[0026] The assembly 21 is further provided with a rotary platform 31, which is coupled to
the slide 24 in a rotary manner so as to rotate, relative to the slide 24, around
a fulcrum axis 32, which is parallel to a vertical direction 33 orthogonal to the
directions 8 and 11 and is obtained at the entrance of the components 2 into the unit
12 and into the channel 23.
[0027] The platform 31 is connected to the slide 24 through the interposition, in particular,
of a shock absorber device 34 and of three coupling devices 35.
[0028] The device 34 comprises, in particular, a pneumatic cylinder 36, which is connected
to the slide 24, a pneumatic cylinder 37, which is connected to the platform 31 and
faces the cylinder 36, and an output rod 38, which is coupled to the two cylinders
36, 37 in a sliding manner.
[0029] Each device 35 comprises a guide 39, which is fixed to the slide 24 parallel to the
direction 11, a recirculating ball slider 40, which is coupled to the guide 39 in
a sliding manner, a guide 41, which is obtained on the slider 40 parallel to the direction
8, a recirculating ball slider 42, which is coupled to the guide 41 in a sliding manner,
and a rolling bearing 43, which is interposed between the platform 31 and the slider
42 so as to allow the platform 31 and the slider 42 to rotate relative to one another
around a rotation axis 44, which is parallel to the direction 33.
[0030] The platform 31 supports a plurality of motor-driven conveyor rollers 45 (in this
case, five rollers 45), which are aligned with one another, face the path P and laterally
delimit the channel 23. One of the rollers 45 (hereinafter indicated with 45a) is
an input roller mounted so as to rotate around the axis 32 and the other rollers 45
(hereinafter indicated with 45b) are mounted so as to rotate around respective rotation
axes 46, which are parallel to one another and to the direction 33.
[0031] The assembly 22 is integral to the slide 16 in the direction 11 and is mounted downstream
of the limit stop device 14 in the direction 8.
[0032] The assembly 22 is provided with a rotary platform 47, which is coupled to the slide
16 in a rotary manner so as to rotate, relative to the slide 16, around a fulcrum
axis 48, which is parallel to the direction 33 and is obtained at the entrance of
the components 2 into the unit 12 and into the channel 23.
[0033] The platform 47 is connected to the slide 16 through the interposition, in particular,
of a shock absorber device 49, which is completely equivalent to the device 34, and
of four coupling devices 50, which are completely equivalent to the devices 35.
[0034] The platform 47 supports a plurality of motor-driven conveyor rollers 51 (in this
case, three rollers 51), which are aligned with one another, face the path P and laterally
delimit the channel 23. One of the rollers 51 (hereinafter indicated with 51a) is
an input roller mounted so as to rotate around the axis 48 and the other rollers 51
(hereinafter indicated with 51b) are mounted so as to rotate around respective rotation
axes 52, which are parallel to the direction 33.
[0035] According to figures 8 and 9, the assembly 22 is further provided with a sanding
device 53 comprising three pulleys 54, which are mounted on the platform 47 with a
triangle-like arrangement and are coupled to the platform 47 so as to rotate, relative
to the platform 47, around respective rotation axes 55, which are parallel to one
another and to the direction 33.
[0036] Two pulleys 54 (hereinafter indicated with 54a) are motor-driven drive rollers, which
are mounted between the rollers 51b and are moved around the relative axes 55 by an
operating device 56 comprising an electric motor 57, which is mounted on the platform
47, and a belt transmission 58, which is interposed between the motor 57 and the pulleys
54a.
[0037] The third pulley 54 (hereinafter indicated with 54b) is a stretching roller, which
is coupled to the platform 47 in a sliding manner so as to move crosswise to the relative
axis 55 and stretch an abrasive belt 59 wound around the pulleys 54a, 54b in a ring
shape.
[0038] The belt 59 is caused to come into contact with the relative face 6 to be sanded
- and held there - by a pushing roller 60, which is mounted between the pulleys 54a
so as to rotate around a longitudinal axis 61 of its parallel to the axes 55 and,
furthermore, is movable around a rotation axis (which is not shown herein), which
is eccentric relative to the axis 61, from and to an operating position, in which
the roller 60 pushes the belt 59 against the relative face 6.
[0039] The device 53 further comprises a synchronizing roller 62, which is arranged within
the belt 59 and is mounted so as to rotate around a longitudinal axis 63 of its, which
is parallel to the axes 55, 61.
[0040] When the roller 60 is in its operating position, the roller 62 is moved crosswise
to the axis 63, due to the thrust of a pneumatic operating device 64, so as to come
into contact with the roller 60 and with one of the pulleys 54a in order to synchronize
the peripheral speeds of the pulleys 54a and of the roller 60 and avoid friction of
the belt 59 on the roller 60.
[0041] The unit 13 is completely similar to the unit 12 and the only difference from the
unit 12 lies in the fact that:
the assembly 21 of the unit 13 is arranged downstream of the assembly 22 of the unit
12 in the direction 8 and the assembly 22 of the unit 13 is arranged downstream of
the assembly 21 of the unit 12 in the direction 8; and
the assembly 21 is integral to the slide 16 in the direction 11, the slide 24 is interposed
between the slide 16 and the platform 47 of the assembly 22 and the assembly 22 is
movable relative to the assembly 21 in the direction 11.
[0042] In use, the component 2 is caused to come into contact with the limit stop device
14 and, then, is moved by the roller conveyor device 7 and by the conveyor assemblies
21, 22 of the operating units 12, 13 in the direction 8 and along the path P.
[0043] The sanding machine 1 has two operating modes of the operating units 12, 13 depending
on the profile of the side faces 6 of each component 2.
[0044] According to a first operating mode, when the faces 6 of the component 2 are flat:
the output rod 20 of the pneumatic cylinders 18, 19 of each unit 12, 13 is locked
in an operating position of its, in which the rod 20 is extracted on the outside of
the relative cylinder 18 and retracted on the inside of the relative cylinder 19;
the output rod 38 of the pneumatic cylinders 36, 37 of the conveyor assembly 21 of
each unit 12, 13 is locked in an operating position of its, in which the rod 38 is
retracted on the inside of the relative cylinder 36 and extracted on the outside of
the relative cylinder 37;
the output rod 38 of the pneumatic cylinders 36, 37 of the conveyor assembly 22 of
each unit 12, 13 is locked in an operating position of its, in which the rod 38 is
retracted on the inside of the relative cylinder 36 and extracted on the outside of
the relative cylinder 37;
the assembly 21 of the unit 12 is moved along the relative slide 16 in the direction
11, so that the distance between the relative rollers 45a and 51a is substantially
equal to a width of the component 2 measured parallel to the direction 11; and
the assembly 22 of the unit 13 is moved along the relative slide 16 in the direction
11, so that the distance between the relative rollers 45a and 51a is substantially
equal to the width of the component 2.
[0045] In this way, the rollers 45a, 45b of the unit 12 and the rollers 51a, 51b of the
unit 13 are aligned with one another in the direction 8, the rollers 51a, 51b of the
unit 12 and the rollers 45a, 45b of the unit 13 are aligned with one another and with
the limit stop device 14 in the direction 8 and the feeding channel 23 has a constant
width, which is equal to the width of the component 2.
[0046] The cylinders 19 fixed to the slides 16 of the two units 12, 13 are supplied with
a pressure which, in any case, is smaller than the thrust exerted by the component
2 upon the assemblies 21, 22 of the two units 12, 13 so as to make up for possible
changes in the shape of the faces 6 of the component 2.
[0047] The cylinders 30 of the shock absorber devices 29 of the two units 12, 13 are supplied
with a pressure which, in any case, is smaller than the thrust exerted by the component
2 upon the assemblies 21, 22 of the two units 12, 13 so as to make up for possible
changes in the width of the component 2 due to production size tolerances.
[0048] According to the other one of the two operating modes mentioned above, when the two
faces 6 of the component 2 are not flat and have a curved profile:
the cylinder 18 of each unit 12, 13 is supplied so as exert, upon the relative rod
20, a thrust which, in any case, is smaller than the thrust exerted by the component
2 upon the assemblies 21, 22 of the two units 12, 13;
the cylinders 36, 37 of the assemblies 21, 22 of each unit 12, 13 are supplied so
as exert, upon the relative rods 38, a thrust which, in any case, is smaller than
the thrust exerted by the component 2 upon the assemblies 21, 22 of the two units
12, 13;
the assembly 21 of the unit 12 is moved along the relative slide 16 in the direction
11, so that the distance between the relative rollers 45a and 51a is substantially
equal to the width of the component 2; and
the assembly 22 of the unit 13 is moved along the relative slide 16 in the direction
11, so that the distance between the relative rollers 45a and 51a is substantially
equal to the width of the component 2.
[0049] In this way, the slide 16 and, hence, the assemblies 21, 22 of each unit 12, 13 are
movable in the direction 11 depending on the profile of the faces 6 of the component
2 and the platforms 31, 47 and, hence, the assemblies 21, 22 of each unit 12, 13 are
movable around the relative fulcrum axes 32, 48 depending on the profile of the faces
6 of the component 2.
[0050] With reference to what described above, it should be pointed out that:
the rotation of the assembly 21 of each unit 12, 13 around the relative axis 32 allows
the relative roller 45a and at least one relative roller 45b to keep engaging the
relative face 6 of the component 2; and
the rotation of the assembly 22 of each unit 12, 13 around the relative axis 48 both
allows the relative roller 51a and at least one relative roller 51b to keep engaging
the relative face 6 of the component 2 and allows the relative belt 59 to always be
in contact with the relative face 6 of the component 2 with a constant thrust.
[0051] When the faces 3, 4 and 6 are connected to one another by means of relative bevelled
edges 65 (figure 10), the path P extends through two further operating units, one
of them (hereinafter indicated with 66) being shown in figures 10 and 11 and being
configured to sand the bottom left edge 65 and the top right edge 65 and the other
one (which is not shown herein) being configured to sand the bottom right edge 65
and the top left edge 65.
[0052] The unit 66 comprises a frame 67, an intermediate slide 68 and a shock absorber device
69, which are completely equivalent to the frame 15, to the intermediate slide 16
and to the shock absorber device 17 of the units 12, 13.
[0053] The slide 68 supports two conveyor assemblies 70, 71 arranged on opposite sides of
the path P in the direction 11.
[0054] The assembly 70 is integral to the slide 68 in the direction 11, is aligned with
the limit stop device 14 in the direction 8 and is provided with a vertical upright
72 projecting upwards from the slide 68 in the direction 33.
[0055] The upright 72 supports a plurality of motor-driven conveyor rollers 73 (in particular,
two rollers 73), which are aligned with one another and with the device 14 in the
direction 8, face the path P, laterally delimit the channel 23 and are mounted so
as to rotate around respective rotation axes 74, which are parallel to the direction
33.
[0056] With reference to figures 12 and 13, the assembly 70 further comprises a sanding
device 75 provided with a first support plate 76, which is mounted on the upright
72 and is inclined relative to the surface A so as to be substantially perpendicular
to the relative edge 65, with a second support plate 77, which is coupled to the plate
76 in a sliding manner so as to move, relative to the plate 76, in the direction 8,
and with a bracket 78, which is coupled to the plate 76 in a rotary manner so as to
rotate, relative to the plate 76 and due to the thrust of an operating device 79,
which is better described below, with an oscillatory reciprocating motion around a
fulcrum axis 80, which is parallel to the plate 76.
[0057] The device 75 has three pulleys 81, which are mounted on the plate 76 with a triangle-like
arrangement, and an abrasive belt 82 wound around the pulleys 81 in a ring shape.
[0058] A first pulley 81 (hereinafter indicated with 81a) is a motor-driven roller mounted
on the plate 76 so as to rotate around a longitudinal axis 83 of its, which is perpendicular
to the plate 76, due to the thrust of an operating device 84 comprising an electric
motor 85, which is fixed to the plate 76, and a belt transmission 86, which is interposed
between the roller 81a and the motor 85.
[0059] A second pulley 81 (hereinafter indicated with 81b) is a stretching roller, which
is mounted on the plate 77 so as to rotate around a longitudinal axis 87 of its parallel
to the axis 83 and is moved by the plate 77 in the direction 8 so as to stretch the
belt 82.
[0060] A third pulley 81 (hereinafter indicated with 81c) is mounted on the bracket 78 so
as to rotate around a longitudinal axis 88 of its, whose orientation depends on the
position of the bracket 78 around the axis 80.
[0061] The oscillatory reciprocating motion of the bracket 78 and, hence, of the pulley
81c around the axis 80 generates a straight reciprocating motion of the belt 82 along
the pulleys 81a, 81b, 81c and, hence, a relatively even wear of the belt 82.
[0062] According to figures 14 and 15, the device 79 comprises a reduction unit 89, which
is fixed to the bracket 78 and has an input shaft 90, which is mounted so as to rotate
around a longitudinal axis 91 of its parallel to the axis 88 and is connected to the
pulley 81c through the interposition of a belt transmission 92.
[0063] The reduction unit 89 is further provided with an output shaft 93 comprising a first
portion 94, which is coupled to the shaft 90 so as to rotate around a longitudinal
axis 95 of its transverse to the axis 91, and a second portion 96, which has a longitudinal
axis 97 parallel to the axis 95, is coupled to the portion 94 in an angularly fixed
manner ans is further coupled to the portion 94 in a sliding manner so as to be moved,
during a set-up phase for setting up the sanding device 75, crosswise to the axis
97.
[0064] The portion 96 is axially locked on the portion 94 by means of a fastening screw
(not shown herein), which extends through a slot 98 obtained in the portion 96, is
screwed into the portion 94 and allows the eccentricity of the axis 97 relative to
the axis 95 to be selectively controlled.
[0065] The portion 96 is engaged in a rotary manner, through the interposition of a rolling
ball bearing which is not shown herein, through a first free end of a connecting rod
99, whose second free end is connected, through the interposition of a ball joint
which is not shown herein, to a coupling pin 100, which projects, crosswise to the
axis 80, from a support bracket 101 fixed to the plate 76 perpendicularly to the plate
76.
[0066] In use, the rotary motion of the pulley 81c around the axis 88 is transmitted by
the belt transmission 92, first of all, to the input shaft 90 and, then, to the output
shaft 93 of the reduction unit 89 so as to move the portion 94 around the axis 95
and the portion 96 around the axis 97.
[0067] Since the portion 96 is engaged through the connecting rod 99, which, in turn, is
connected to the bracket 101 and, hence, to the plate 76, the portion 94 is caused
to rotate around the eccentric axis 97, thus generating the oscillatory reciprocating
motion of the bracket 78 around the axis 80.
[0068] The oscillatory reciprocating motion of the pulley 81a around the axis 80 generates
a straight reciprocating motion of the belt 82 along the pulleys 81a, 81b, 81c parallel
to the relative axes 83, 87, 88 and a substantially even wear of the belt 82 over
a relatively large width of the belt 82.
[0069] The straight reciprocating motion of the belt 82 along the pulleys 81a, 81b, 81c
has a back stroke and a forth stroke, which are independent of the speed of movement
of the belt 82 around the pulleys 81a, 81b, 81c, depend on the width of the oscillation
of the bracket 78 around the axis 80 and, hence, on the eccentricity between the axes
95 and 97 and are selectively controlled by changing the eccentricity between the
axes 95 and 97.
[0070] The device 76 further comprises a pushing element 102, which is mounted between the
pulleys 81b and 81c and is movable, due to the thrust of a pneumatic actuator cylinder
103 fixed to the plate 76, between a forward operating position, in which the element
102 causes the belt 82 to come into contact with the relative edge 65, and a retracted
rest position, in which the belt 82 disengages the edge 65.
[0071] With reference to figures 10 and 11, the assembly 71 is arranged on the side of the
path P opposite the one of the device 14 and comprises a horizontal slide 104, which
is mounted on the slide 68 and is coupled to the slide 68 in a sliding manner so as
to make straight movements along the slide 68 in the direction 11 due to the thrust
of an operating device, which is completely equivalent to the operating device 26,
and through the interposition of a shock absorber device, which is completely equivalent
to the shock absorber device 29.
[0072] The slide 104 extends upwards in the direction 33 and supports a plurality of motor-driven
conveyor rollers 105 (in particular, two rollers 105), which are aligned with one
another in the direction 8, face the path P, laterally delimit the channel 23 and
are mounted so as to rotate around respective rotation axes 106, which are parallel
to the direction 33.
[0073] The slide 104 is engaged in a sliding manner by a vertical slide 107, which, during
a set-up phase for setting up the assembly 71, is moved by an operating device 108
along the slide 104 in the direction 33 depending on a height of the component 2.
[0074] The slide 107 supports a sanding device 109, which is completely equivalent to the
sanding device 75 and is hinged to the slide 107 so as to rotate, relative to the
slide 107 and due to the thrust of a pair of actuator cylinders 110, around a fulcrum
axis 111, which is substantially parallel to the direction 8, between an operating
position, in which the device 109 sands the relative edge 65, and a rest position,
which is suited to allow the belt 82 to be replaced.
[0075] The operating unit (not shown) mounted downstream of the unit 66 in the direction
8 is completely equivalent to the unit 66 and the only difference from the unit 66
lies in the fact that:
the assembly 71 of the operating unit (not shown) is arranged downstream of the assembly
70 of the unit 66 in the direction 8 and the assembly 70 of the operating unit (not
shown) is arranged downstream of the assembly 71 of the unit 66 in the direction 8;
and
the assembly 71 is integral to the slide 68 in the direction 11, the slide 104 is
interposed between the slide 68 and the upright 72 of the assembly 70 and the assembly
70 is movable relative to the assembly 71 in the direction 11.
[0076] According to some embodiments that are not shown:
the sanding devices 53 and/or 75 and/or 109 are eliminated and replaced by alternative
sanding tools, for example brushes; and
the pneumatic cylinders 18, 19, 36, 37 are eliminated and replaced by alternative
shock absorber devices, for example hydraulic actuators, electric cylinders, brushless
servo-motors.
1. - A sanding machine for sanding/finishing/brushing components (2) made of wood, metal
or the like; the sanding machine comprising at least one sanding unit (66) for sanding/finishing
the component (2); and a feeding device (7), which defines a support surface (A) for
at least one component (2) and is designed to feed the component (2) in a first direction
(8), which is parallel to the support surface (A), and along a path (P) extending
through the sanding unit (66); the sanding unit (66) comprising a frame (76), at least
two pulleys (81a, 81b, 81c), which are mounted so as to rotate around respective longitudinal
axes (83, 87, 88), an abrasive belt (82), which is wound in a ring shape around the
pulleys (81a, 81b, 81c), and an operating device (79) to move a first pulley (81c)
with an oscillatory reciprocating motion around a rotation axis (80), which is transverse
to the relative longitudinal axis (88); and being characterized in that the operating device (79) comprises two transmission shafts (94, 96), which are coupled
to one another in an angularly fixed manner so as to rotate around respective longitudinal
axes (95, 97), which are eccentric to one another, a first transmission system (89,
92) to connect a first transmission shaft (94) and the first pulley (81c) to one another,
and a second transmission system (99, 100) to connect a second transmission shaft
(96) and the frame (76) to one another.
2. - The sanding machine according to claim 1, wherein the first transmission system (89,
92) comprises a reduction unit (89), which is provided with an input shaft (90), and
a belt transmission (92) to connect the first pulley (81c) and the input shaft (90)
to one another; the transmission shafts (94, 96) defining an output shaft (93) of
the reduction unit (89).
3. - The sanding machine according to claim 1 or 2, wherein the second transmission system
(99, 100) comprises a first coupling member (99) which is connected to the second
transmission shaft (96), and a second coupling member (100) to connect the first coupling
member (99) and the frame (76) to one another.
4. - The sanding machine according to claim 3, wherein the second transmission shaft
(96) is engaged in a rotary manner through the first coupling member (99) with the
interposition of a spherical bearing.
5. - The sanding machine according to claim 3 or 4, wherein the first coupling member
(99) and the second coupling member (100) are connected to one another with the interposition
of a ball joint.
6. - The sanding machine according to any one of the preceding claims, wherein the transmission
shafts (94, 96) are coupled so as to radially move relative to one another and selectively
control the eccentricity between the relative longitudinal axes (95, 97).
7. - The sanding machine according to any one of the preceding claims, wherein the sanding
unit (66) comprises a support bracket (78), which is mounted so as to rotate around
the rotation axis (80); the first pulley (81c) being mounted on the support bracket
(80).
8. - The sanding machine according to any one of the preceding claims, wherein the sanding
unit (66) further comprises a further operating device (84) to move the pulleys (81a,
81b, 81c) around the relative longitudinal axes (83, 87, 88).