Title of Invention

METHOD AND SYSTEM FOR CHECKING THE POSITION OF A MECHANICAL PART WITH A LIGHT BEAM

Abstract The invention relates to a method for checking the position of a mechanical part (2) along at least one checking direction (X) by means of an apparatus (1) including a device (6) for generating a light beam (7) along a trajectory (Y) transversal to said checking direction (X), a sensor (8) for detecting the interruption of the light beam (7), and devices (3) for causing mutual displacements between the mechanical part (2) and the light beam (7) along said checking direction (X) and along an inspection direction (Z) transversal to the checking direction (X). The method comprising: identifying (19) a first linear interval (X1) and a second linear interval (Z1) of the mutual positions between mechanical part (2) and light beam (7) along the checking direction (X) and, respectively, the inspection direction (Z), said first linear interval (X1) and said second linear interval (Z1) defining a checking area (13) of the mechanical part (2), controlling a sequence of checking displacements between mechanical part (2) and light beam (7), comprising displacements (29) for bringing the light beam (7) to inspection positions (Pi; P1-P4) of the first linear interval (X1), and at said inspection positions (Pi ; P1-P4), linear inspection movements (30) along said inspection direction (Z), detecting (31-34) the interruption or the non- interruption of the light beam (7) in the course of said linear inspection movements along the inspection direction (Z), and consequently selecting (35,36, 38) the subsequent of said inspection positions (Pi ; P1-P4) of the first linear interval (X1) at which the subsequent linear inspection movements are controlled, stopping (37) the sequence of checking displacements at a final inspection position (PN) of the light beam (7) in the first linear interval (X1) that lies at a distance (D) less than a preset value (W) from a previous inspection position (Pi; P1-P4), where, in the course of linear inspection movements at said final inspection position (PN) and said previous inspection position (Pi; P1-P4) in the first linear interval (X1), there have been detected, respectively, the interruption (32,34) and the non-interruption (31,33) of the light beam (7), or vice versa, and identifying (41) the position of the mechanical part (2) along the checking direction (X) on the basis of said final inspection position (PN).
Full Text METHOD AND SYSTEM FOR CHECKING THE POSITION OF A MECHANICAL PART WITH A LIGHT
BEAM
Technical Field
The present invention relates to a method for checking the
position of a mechanical part along at least one checking
direction by means of an apparatus including a device for
generating a light beam along a trajectory transversal to
the checking direction, a sensor for detecting the
interruption of the light beam, and devices for causing
mutual displacements between the mechanical part and the
light beam along the checking direction and along an
inspection direction transversal to the checking direction.
This invention also relates to a system for checking the
position of a tool coupled to the turret of a machine tool.
Background Art
Apparatuses for automatically checking the position or the
integrity of tools are often utilized in machine tools of
various types as, for example, numeric control machining
centers where the condition of the tools can be checked in
the course of the actual machining phase when the tool is
coupled to the rotating spindle.
Known apparatuses and methods perform checkings of this
type, i.e. determine the presence, the position, the
dimensions and possible breakages of tools, by utilizing
feelers for contacting the tools, or contactless systems
as, for example, optical systems that employ light rays or
beams.
U.S patent No. US-A-3912925 discloses a drilling machine in
which devices for checking the integrity of the tools
utilize transversal light beams with limited thickness. The
beams are substantially coplanar to the feed direction of

the tools. The non-interruption of a light beam at a
specific position of the tool is detected and notifies an
anomalous condition of the tool.
Different applications of optical or optoelectronic systems
for checking the position and/or the dimensions of non-
rotating tools with profile not a priori precisely known
present specific problems. This is the case, for example,
when checking tools located in the tool-holder ("turret")
of a lathe and it is required to accurately check the
position of the cutting edge of these tools.
A specific problem rises whenever expensive and delicate
devices with thick linear sensors that employ an equally
thick light beam enabling to detect and to analyze the
entire profile of" the tool (for example "shadow-casting"
systems) cannot be used and it is desired to utilize
apparatuses in which there is simply detected the
interruption of a light beam (for example a laser beam)
with limited thickness. The posed problem is to find the
correct arrangement between tool and light beam that
enables the former to interfere with the latter at the
significative dimension to be checked, since the position
of the significative dimension along the entire profile of
the tool is not a priori known.
A solution proposed, for example, in patent No. US-A-
3749500 (figure 17, column 16, lines 4-21) is to arrange
the optoelectronic apparatus in such a way that the beam
lies in the plane that includes the profile of the tool to
be checked, substantially perpendicular to the direction of
the dimension to be checked. In many cases this possible
solution is not applicable by reasons of insufficient room
available. Moreover such solution is not really flexible
because it does not enable to carry out checkings of
different tools - for example, tools mounted in different
positions on the same turret - the significative profile of
which, i.e. the profile that includes the cutting edge to
be checked, lies in different planes. Therefore, it is
necessary to add complexity to the system by foreseeing the

possibility of displacing the beam perpendicularly to the
planes of the profiles or vice versa and to identify the
correct position by performing an additional scan in said
direction.
Furthermore, the checkings that the solution disclosed in
patent No. US-A-3749500 enables to perform are limited to a
single direction along the significative profile plane,
i.e. perpendicular to the light beam. This means the
preclusion, unless arranging a plurality of light beams in
other ways, to checkings of tools with cutting edges that
include - as often occurs - conceptually punctiform working
areas with different orientations along the significative
profile plane.
Therefore, it is preferred to resort to a different
arrangement of the optoelectronic apparatus, in which the
light beam lies in a transversal direction (more
particularly, a perpendicular direction) to the plane of
the tool profile.
Figure 1 schematically shows a cross-section view along
plane X-Z of a mechanical part U that includes an end point
C, along direction X, the position thereof is to be checked
along the same direction X (checking direction). Figure 1
also shows the cross-section view along the same plane X-Z
of a light beam R arranged along a direction Y
perpendicular to the plane X-Z. The mechanical part U
schematically represents, for example, a tool mounted in
the turret of a lathe and including, in a position along
the plane X-Z not a priori known, a cutting edge C the
position of which along the direction X is to be located.
A method of performing the checking foresees identifying
the trend of the profile B - not a priori known - of the
part U along the cross-section plane, by a point scan of
the profile. If the tool to be checked is located in the
turret of a lathe, the scan is performed, for example, by
displacing the turret along directions X and Z according to
sequences of a known type, by detecting interruptions of
the light beam R at a plurality of points of the profile B,

and by performing processings, also of a known type, including, for example,
interpolations for locating points of the profile B not "contacted" by the beam R.
This known method may pose reliability problems bound to the selected scan
interval, type of scan (greater or lesser number of points to be checked and
consequent longer or shorter involved time) and consequent necessary
processings. In fact, an inaccurate or incomplete detection of the profile may
cause- in the formerly mentioned example- the missed identification of the point
C of maximum projection in the direction X, the position of which has to be
checked.
In any case, the known method is time consuming and involves complex
processings.
Summary of the Invention
An object of the present invention is to provide a method and a system for
checking the position of a tool, more specifically the cutting edge of a tool the
profile of which is not known a priori, that is simple and reliable, overcoming the
disadvantages that the known methods and systems present.
Among the advantages that the method according to the present invention and
the associated system provide, there are the remarkable rapidity of the feasible
checkings and the possibility of identifying-by means of the same apparatus and
in an extremely simple and rapid way- the position of working areas of the tool,
i.e. the points of the cutting edge oriented for performing machinings along
different directions.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS.

The invention will now be described with reference to the
enclosed sheets of drawings, given by way of non limiting
example only, wherein:
figure 1 is a schematic and partial representation of
a mechanical part to be checked by means of a method
according to the invention;
figure 2 shows in simplified form an application on a
machine tool that implements a system according to the
invention;
figure 3 is an enlarged and partial view of a tool of
the machine tool of figure 2, along direction Y in figure
2;
figure 4 is a diagram with blocks that represent the
various steps of a method according to the invention; and
figure 5 is a furtherly enlarged and partial view of
the tool shown in figure 3, including a graphical
representation of a sequence of displacements in a checking
method according to the invention.
Best Mode for Carrying Out the Invention
Figure 2 illustrates, in an extremely schematic form, a
checking system including an optoelectronic apparatus 1 in
the course of checking a mechanical part 2, more
specifically a tool located in a turret 3 of a lathe 4 to
which the apparatus 1 is coupled. Typically, the turret 3
carries other tools, not shown in the schematic
representation of figure 1. The apparatus 1 includes an
emitter 6, i.e. a device for generating a light beam 7, for
example a laser beam, along a transversal trajectory
substantially parallel to direction Y, and a receiver 8,
i.e. a sensor, arranged along said trajectory, that detects
the correct reception of the light beam 7 or the non-
reception of light owing to the interruption of the beam 7.
A processing unit 9 is electrically connected to the
emitter 6 and to the receiver 8. The system includes a
control unit 10, connected to the processing unit 9, for

controlling in a known way, by means of suitable activation
devices also known and not illustrated in the figure, the
machining movements of the lathe 4 in plane X-Z of the
turret 3 that carries the tool 2. For the sake of
simplicity and for the reason it is beyond the object of
the present invention, a spindle of a known type holding a
piece to be checked arranged, for example, in the direction
Y, is not illustrated.
The surface contour or profile of the tool 2 in the plane
X-Z is shown enlarged in figure 3, where a checking area 13
of the position of the tool 2 is delimited by a first
linear interval X1 and by a second linear interval Z1. The
first linear interval X1 and the second linear interval Z1
along the checking direction X and an inspection direction
Z, respectively, are defined on the basis of the
approximately known nominal dimensions of the tool 2 and
delimit the mutual positions that tool 2 and light beam 7
can take in the course of the checking, as hereinafter
described. The correct arrangement and dimensions of the
area 13 are defined in an initial phase of the checking
cycle, as hereinafter also described.
The blocks of the diagram of figure 4 refer to a procedure
for checking the position of a working area 11 of the tool
2 along the direction X. In an entirely analogous and
symmetrical way - not hereinafter described - the checking
of the position of a working area 12 of the tool 2 along
the direction Z is implemented. The various steps of the
procedure and the mutual movements between the tool 2 and
the light beam 7 can be checked, for example, by the
control unit 10.
The meaning of the blocks represented in figure 4 is
hereinafter briefly described.
block 18 - start of the checking cycle;
block 19 - acquisition, for example by means of the
control unit 10 of the lathe 4, of the data relating to a
tolerance value W and to the approximate nominal dimensions
of the tool 2, and consequent setting of the checking area

13;
block 20 - displacements between tool 2 and beam 7 for
bringing the latter to a first predetermined vertex 14 of
the perimeter of the checking area 13;
block 21 - test about interruption or non-interruption
of the beam 7 at the vertex 14;
block 22 - modifications of the checking area 13 and of
the mutual arrangement tool 2 / beam 7;
block 23 - displacements between tool 2 and beam 7 along
the perimeter of the checking area 13 starting from a
vertex (14,15,16);
block 24 - test in connection with the reaching of the
subsequent vertex (15,16,17);
block 25 - test about the interruption of the beam 7;
blocks 26 and 27 - tests for determining whether the in-
progress displacement is the last foreseen (between the
vertexes 16 and 17);
block 28 - initial setting of procedure parameters, i.e.
indicator TO of the result of the immediately previous
checking, indicator V of the sense of the next displacement
along the checking direction X, amount D of the next
displacement, in addition to the value of a reduction
factor FR of the subsequent displacements along the
checking direction X;
block 29 - displacement between tool 2 and light beam 7
for bringing the beam 7 to a determined inspection position
Pi; this displacement includes a component along the
checking direction X of amount D in the sense V;
block 30 - linear inspection movement between tool 2 and
beam 7 along the second direction Z in the linear interval
21;
block 31 - test for determining the completion of the
inspection movement in the entire linear interval Z1;
block 32 - test for determining the interruption of the
beam 7 in the course of the inspection movement;
block 33 - indication of the non-interruption of the
beam 7 in the course of the inspection movement (T=0);

block 34 - indication of the interruption of the beam 7
in the course of the inspection movement (T=l);
block 35 - comparison between the values of the
indicators T and TO;
block 36 - confirmation of the sense V of the next
displacement along the checking direction X;
block 37 - test for determining the end of a search
phase on the basis of a comparison between the tolerance
value W and the distance D between recent mutual positions
between beam 7 and tool 2 in the direction X;
block 38 - reversal of the sense V of the next
displacement along the checking direction X;
block 39 - updating of some parameters (T0←T; D←D/FR) ;
block 40 - comparison between the inspection position PN
of the beam 7 in the checking direction X at the end of the
search phase and a corresponding position defined in a
calibration phase;
block 41 - end of the checking cycle.
The checking of the position of the working area 11 of the
tool 2 along the direction X by following the procedure of
figure 4, that represents a possible embodiment of a method
according to the present invention, occurs in the following
way.
At first (block 19), depending on the values of the
approximate nominal dimensions of the tool 2 and on the
known arrangement of the tool 2 in the turret 3 with
respect to the reference system of the machine tool, the
first linear interval X1 and the second linear interval Z1,
that locate the checking area 13 within which the checking
displacements between tool 2 and beam 7 are limited, are
defined.
Then a preliminary verification phase follows for verifying
whether the set linear intervals (X1 and Z1) enable the
correct performing of the checking. In order to do this,
the tool 2 and the beam 7 are displaced with respect to
each other (block 20) in order to bring the latter to a
vertex 14 of the rectangle that delimits the area 13. If

the interruption of the beam 7 (block 21) at the vertex 14
is observed, it means that the checking area 13 has not
been correctly selected. As a consequence, the preliminary
phase is interrupted, displacements of the tool 2 are
controlled for bringing the beam 7 to a position definitely
at the exterior of the area 13, and fresh linear intervals
X1 and Z1 (block 22) are set. If the interruption of the
beam 7 is not observed, mutual linear displacements (block
23) are controlled in sequence for bringing the beam 7 from
a vertex (14,15,16) towards the subsequent one (15,16,17)
along the sides of the rectangle that delimits the area 13.
At every displacement it is verified whether the subsequent
vertex has been reached (block 24) . The preliminary phase
is interrupted and the limits of the checking area 13 are
.reset (block 22) whenever there occur anomalies. The
anomalies are signalled by interruptions of the beam 7 in
the course of the displacements towards the vertexe's 15 and
16 (blocks 25 and 27) or, in the last foreseen displacement
- i.e. an inspection movement in the direction Z starting
from the vertex 16 - by the non-interruption of the beam 7
and the reaching of the vertex 17 (blocks 24 and 26) . The
verification preliminary phase otherwise positively ends
when the beam 7 is correctly interrupted in the course of
the inspection movement that starts from the vertex 16
(block 27).
Then the initial or absolute values of some parameters
utilized in the subsequent actual checking phase are set
(block 28) . The parameters are hereinafter briefly
described.
TO: it indicates the result of the immediately
previous inspection with respect to the in-progress one,
i.e. it indicates whether, in the course of the previous
inspection movement between tool 2 and beam 7 (the
following explanation refers) the interruption of the
latter occurred (T0=1) or did not occur (T0=0). At first,
TO is set, for example, at value 1, also on the basis of
the conclusion of the verification phase.

V: it indicates the sense of the next mutual
displacement between tool 2 and beam 7 (the following
explanation refers) insofar as the component in the
checking direction X is concerned. With reference to figure
3, V=l and V=0 indicate, for example, displacements to the
right and to the left, respectively. At first V is set, for
example, at value 1.
D: it is the amount of the displacement along the
direction X to which V refers. At first D is set, for
example, at a value that corresponds to the length of
interval X1 reduced by the reduction factor FR (hereinafter
described).
FR: it is the reduction factor relating to each
displacement in direction X that follows in the checking
sequence. In general, it is a fixed value. In the herein
described example FR=2, i.e. the amount of the displacement
along X is halved every time with respect to the previous
displacement along the same direction X.
The search phase of the position of the working area 11 of
the tool 2 foresees a sequence of checking displacements
between tool 2 and beam 7 starting from the position taken
at the end of the preliminary phase in which the beam 7 is
at a point on the side defined by vertexes 16 and 17 that
delimits the first linear interval X1. It should be
realized that, in the present description, the search phase
is distinguished from the preliminary phase described above
with reference to the blocks 20-27 for more clearly
describing a method according to the invention. The search
phase actually follows the preliminary phase with
substantial continuity.
A displacement (block 29) between the tool 2 and the beam 7
towards a determined mutual position is controlled so that
the beam 7 displaces to a determined inspection position Pi
on the lower side (with reference to the arrangement shown
in figure 3) of the checking area 13, at a distance along
axis X determined on the basis of the parameters V and D.
More specifically, the sense V and the amount D of the

first displacement in direction X with respect to the
vertex 16 are those previously set (V=1; D=X1/FR=X1/2) .
At inspection position Pi in the interval X1, a linear
inspection movement is controlled (block 30) along
direction Z and it interrupts when one of the two following
events occurs (i) the reaching of the opposite side of the
checking area 13 when the beam 7 has travelled, in the
linear movement, the entire interval Z1 (block 31); or (ii)
the interruption of the beam 7 signalled by the
optoelectronic apparatus 1 (block 32). The event regarding
the occurred interruption (T=1, block 34) or non-
interruption (T=0, block 33) of the beam 7 is compared
(block 35) with the corresponding event that occurred in
the immediately previous inspection, indicated by the
parameter TO and, depending on whether the event has or has
not repeatedly occurred, the sense in which the subsequent
displacement along direction X will occur is held (V←V,
block 36) or reversed (V←invV, block 38), respectively.
The , values of some parameters are updated (T0←T,
D←D/FR=T1/4, block 39) and the checking sequence is
repeated starting from a fresh displacement (block 29)
between tool 2 and beam 7 towards a fresh determined mutual
position, in such a way that the beam 7 displaces to a
fresh inspection position Pi at the lower side of the
checking area 13, at a distance from the previous
inspection position set on the basis of the values of
parameters V and D. A fresh linear inspection movement
(block 30) along direction 2 is controlled at the fresh
inspection position Pi in the interval X1.
The sequence of checking displacements ends when, after
having verified that T ≠ TO (block 35) , the distance D
between the current position and a previous one of the beam
7 in the interval X1, more specifically the immediately
previous position, is less than the prefixed tolerance
value W (block 37) .
The final inspection position PN taken by the light beam 7
in the linear interval X1 at the end of the sequence of

checking displacements is compared with the corresponding
position detected in a previous calibration phase on a
master piece for determining the position of the working
area 11 of the tool 2 to be checked (block 41). Calibration
is performed in a known way for correlating the absolute
position of the machine axes of the lathe 4 with the one of
the area 11 to be checked in a suitable reference system.
If the position of the master piece with respect to the
machine axes is known, a possible calibration procedure,
herein not detailedly described for the sake of simplicity,
can be performed on the master piece in a substantially
identical way with respect to the one described with
reference to the blocks 19-39 of the diagram shown in
figure 4.
Then, from the position of the working area 11 and by
knowing, as formerly mentioned, the arrangement of the tool
2 in the turret 3 with respect to the reference system of
the machine tool, the dimensions of the tool 2 in the
checking direction X can be determined.
In figure 5 the checking area 13 is furtherly enlarged and
there are shown the linear inspection movements along
direction Z (as uninterrupted lines) and the displacements
with component in direction X (as dashed lines). In the
example illustrated in figure 5, it is presumed that the
tolerance value W is equal to a tenth of the amplitude of
the interval X1 (X1/10) . This value has been chosen just
for the sake of simplifying the explanation of the cycle,
and is definitely greater than an actual tolerance value.
Furthermore, also for the sake of simplifying the
explanation, movements of the light beam 7 in the checking
area 13 are reported, while in the real applications the
beam 7 is generally stationary with respect to the bed of
the machine tool 4 (figure 2) and the turret 3 carrying the
tool 2 (to which the area 13 is associated) performs
movements in the plane X-Z. This corresponds to the
substance of the method that includes, according to the
invention, mutual movements between tool 2 and beam 7.

With reference to figure 5 and to the orientation therein
shown, at the end of the preliminary phase for the
verification of the checking area 13 (blocks 25 and 27) ,
the beam 7 interferes with the tool 2 at the side between
the vertexes 16 and 17 that delimits the linear interval
X1. The beam 7 is brought back to the lower side of the
checking area 13 displaced to the right with respect to the
vertex 16 (V=1, block 28) of the amount D=X1/2 up to
inspection position P1 (block 29) where an upward
inspection movement in the direction 2 is controlled (block
30) . Since the interruption of the beam 7 is detected
again, a fresh downward and, in the interval X1, rightward
displacement of an amount halved with respect to the
previous one (D=X1/4) takes place, up to inspection
position P2. The subsequent inspection movement at P2
causes a different event, i.e. the reaching of a point P2'
at the opposite end of the interval 21, on the upper side
of the checking area 13 (blocks 31, 33). As T(=0) ≠ T0(=1)
(block 35), the sense of the displacement along X is
reversed (V← invV = 0, block 38) and the beam 7 is brought
back to the lower side of the checking area 13 displaced to
the left with respect to P2 of the amount D = (X1/4)/2 =
X1/8 up to inspection position P3. At the subsequent
inspection movement at P3, the event changes again
(interruption of the beam 7) and thus the sense V of the
subsequent displacement changes again (V← invV = 1, block
38) on the lower side of the area 13 and to the right, up
to inspection position P4 that is distant from P3 in the
checking direction X of the amount D = (X1/8)/2 = X1/16. A
fresh inspection movement ends when the beam 7 reaches the
upper side of the checking area 13, at a point P4' (blocks
31, 33) . As T ≠ T0 (block 35) and D block 37), the sequence of checking displacements ends, and
the position of the working area 11 is determined (block
41) on the basis of the final inspection position PN = P4
in the linear interval X1.
The illustrated example clearly shows how the position of

the working area 11 is found by means of a limited number
of scans in the transversal inspection direction Z at
inspection positions along the checking direction X at
distances D progressively decreasing with respect to each
other in a sequence that converges to the searched
position. As already mentioned in the example illustrated
with reference to figure 5, the tolerance value W has been
chosen of a different order of magnitude with respect to
what is normally requested and the displacements along the
checking direction X, required for completing the checking
cycle, are limited to four. In any case the example clearly
demonstrates how rapidly the sequence of inspection
positions Pi along the checking direction X converges to
the searched position PN. In a real example, where the
interval X1 is of a few millimeters and the tolerance value
W is of a few microns, the necessary inspection movements
are generally equal to or slightly greater than ten.
The described procedure represents just an example of a
checking method according to the invention that foresees
many possible variants. For example, the sequence of
checking displacements can start from a mutual position
that differs from the one described (that is determined in
the preliminary verification phase), in case that, for
example, the verification phase is unnecessary or is
performed at a different moment in time. Moreover, the
sequence of checking displacements can be stopped on the
basis of the result of a different test, for example the
comparison of the set tolerance W not with the distance D
between the last two consecutive inspection positions Pi at
which there have occurred opposite events, but with the
distance between the current inspection position Pi and the
last inspection position Pi at which there occurred the
event opposite to the current one, regardless of the
comparison between the events relating to the last two
consecutive inspection positions Pi.
Other variants can regard the implementation of the
displacements. Just as an example, three possible aspects

that differ with respect to what has been herein so far
described and illustrated are cited.
- A reduction factor FR different from 2 can be chosen,
for example it can be 3, or can assume a value that
varies in the course of the checking cycle, for keeping
into account the sequence of the events that have taken
place. However, the reduction factor FR is chosen in
such a way that the succession of the inspection
positions Pi on the checking direction X converges to
the position of the Working area the position thereof
has to be checked.
The inspection positions Pi in the interval X1 can be in
the upper side (according to the arrangement shown in
the figures) of the checking area 13, or alternatively
in the lower side and in the upper one. This latter
solution can be advantageously applied, for example,
further to the occurring of the event according to which
the interruption of the beam 7 is not detected. In this
case, in the example of figure 5, the beam 7 is
displaced from point P2' to a closer point P3' on the
upper side of the area 13 that corresponds, in the
interval X1, to the inspection position P3, whereas the
subsequent linear inspection movement in the direction Z
(block 30) occurs, as a consequence, downwards.
The displacements that follow the inspection movements
occur, in the example shown in figure 5, with
interpolated movements that include components along
both directions X and Z ("saw-toothed movements").
Obviously this is not the only possible solution and the
displacements can occur in two distinct phases (for
example: return to the side of the checking area by a
movement along Z, followed by a linear movement along X
to the inspection position Pi).
As previously described, the description and the figures
refer to the checking of the position along the axis X. By
following an identical procedure, it is possible to check
positions of working areas along the direction Z (area 12

in figure 3) or along other transversal directions of the
plane X-Z.
This is particularly advantageous as it enables to carry-
out a complete verification of the cutting edges of the
tools for checking associated points, or working areas,
oriented in different directions. In the example shown in
simplified form in figure 3, both the working areas 11 and
12 can be, for example, simply and rapidly checked in
sequence.
A method according to the invention enables the checking of
different types of tools in different applications, and in
general mechanical parts of various type (for example,
workpieces before or after the machining) .

We CLAIMS
1. A method for checking the position of a mechanical part (2) along at least
one checking direction (X) by means of an apparatus (1) including a device
(6) for generating a light beam (7) along a trajectory (Y) transversal to said
checking direction (X), a sensor (8) for detecting the interruption of the light
beam (7), and devices (3) for causing mutual displacements between the
mechanical part (2) and the light beam (7) along said checking direction (X)
and along an inspection direction (Z) transversal to the checking direction
(X), the method being characterized by the following steps:
identifying (19) a first linear interval (X1) and a second linear interval (Z1) of
the mutual positions between mechanical part (2) and light beam (7) along the
checking direction (X) and, respectively, the inspection direction (Z), said first
linear interval (X1) and said second linear interval (Z1) defining a checking area
(13) of the mechanical part (2),
controlling a sequence of checking displacements between mechanical part
(2) and light beam (7), comprising
displacements (29) for bringing the light beam (7) to inspection positions (Pi;
P1-P4) of the first linear interval (X1), and
at said inspection positions (Pi ; P1-P4), linear inspection movements (30)
along said inspection direction (Z),
detecting (31-34) the interruption or the non- interruption of the light beam (7)
in the course of said linear inspection movements along the inspection direction
(Z), and consequently selecting (35,36, 38) the subsequent of said inspection
positions (Pi ; P1-P4) of the first linear interval (X1) at which the subsequent
linear inspection movements are controlled,
stopping (37) the sequence of checking displacements at a final inspection
position (PN) of the light beam (7) in the first linear interval (X1) that lies at a

distance (D) less than a preset value (W) from a previous inspection position (Pi;
P1-P4), where, in the course of linear inspection movements at said final
inspection position (PN) and said previous inspection position (Pi ; P1-P4) in the
first linear interval (X1), there have been detected, respectively, the interruption
(32,34) and the non-interruption (31,33) of the light beam (7), or vice versa, and
identifying (41) the position of the mechanical part (2) along the checking
direction (X) on the basis of said final inspection position (PN).
2. The method as claimed in claim 1, wherein said inspection positions (Pi; P1-
P4) of the first linear interval (X1) are selected at distances (D) progressively
decreasing from each other according to a convergent sequence.
3. The method as claimed in claim 2, wherein said inspection positions (Pi; P1-
P4) of the first linear interval (X1) are selected at distances (D) progressively
halved from each other.
4. The method as claimed in claim 2 or claim 3, wherein said displacements (29)
for bringing the light beam (7) to inspection positions (Pi; P1-P4) of the first linear
interval (X1) are controlled in a sense (V) or in the opposite sense along said
checking direction (X) as a consequence (35) of the detecting of the interruption
(32,34) or the non-interruption (31,33) of the light beam (7) in the course of the
linear inspection movements at the two most recent inspection positions (Pi; P1-
P4).
5. The method as claimed in one of the preceding claims, comprising a
preliminary verification phase of said checking area (13) with displacements
between light beam (7) and mechanical part (2) between predetermined points
(14,15,16,17) of the checking area (13).

6. The method as claimed in claim 5, wherein said preliminary verification phase
comprises at least one of said linear inspection movements along the inspection
direction (Z).
7. The method as claimed in one of the preceding claims, wherein said linear
inspection movements along said inspection direction (Z) are interrupted as soon
as the interruption of the light beam (7) is detected (32).
8. The method as claimed in one of the preceding claims, wherein the trajectory
(Y) of said light beam (7) and said checking area (13) are substantially
perpendicular.
9. The method as claimed in one of the preceding claims, wherein in the step of
stopping (37) the sequence of the checking displacements, said previous
inspection position (Pi; P1-P4) is the immediately preceding position with respect
to the final inspection position (PN).

10. The method as claimed in one of the preceding claims, wherein said light
beam is a laser beam (7).
11. A method as claimed in claim 1, wherein the controlling, detecting and
stopping steps comprise:
(a) a linear inspection movement (30) along said inspection direction (Z) within
the checking area (13), till there occurs one of the following events
(i) interruption (32,34) of the light beam (7), or
(ii) covering (31,33) of the entire second linear interval (Z1) with no interruptions
of the light beam (7),

(b) a displacement (29) along the checking direction (X), in a determined sense
(V), up to an inspection position (Pi ; P1-P4) of the light beam (7) in said first
linear interval (X1),
(c) the repetition of the linear inspection movement (30) along the inspection
direction (Z) according to step (a),
(d) a fresh displacement (29) along the checking direction (X) in the sense (V) of
the previous displacement, or in the opposite sense, according to (35) whether
the event (i) or (ii) that occurred (31-34) in the most recent linear inspection
movement (30) be or not be the same that occurred in the previous linear
inspection movement (30), up to a fresh inspection position (Pi ; P1-P4) of the
light beam (7) in said first linear interval (X1), at a known distance (D) with
respect to the immediately previous inspection position (Pi; P1-P4),
(e) the repetition of linear inspection movements and displacements, according to
steps (c) and (d)- with progressively decreasing distances (D) between the fresh
inspection positions (Pi; P1-P4) and the immediately previous inspection
positions (Pi; P1-P4) of the light beam (7) in said first linear interval (X1)-till
(35,37) the distance (D) between the fresh inspection position (Pi, PN; P1-P4)
and a previous inspection position (Pi; P1-P4)-at which the linear inspection
movement causes the occurring of one of the events (i) and (ii) and, respectively,
the opposite event-is less than a prefixed value (W), and the
identifying (41) step takes place on the basis of the fresh inspection position
(PN) of the light beam (7) in said first linear interval (XI) at the end of the
sequence of checking displacements.
12. A system for checking the position of a working area (11,12) of a tool (2)
coupled to a turret (3) of a machine tool (4), along at least one checking direction
(X), comprising:
a device (6) for generating a light beam (7) along a trajectory (Y) transverse to
said at least one checking direction (X); a sensor (8) for detecting interruption of
the light beam (7); devices (3) for causing relative displacements between the
tool (2)and the light beam (7) along said at least one checking direction (X) and
along an inspection direction (7) transverse to the at least one checking direction
(X); and
a control unit (10) that is configured to:
control a sequence of checking displacements between said tool and said light
beam, including displacements for bringing the light beam to inspection positions
along said at least one checking direction, and, at said inspection positions,
linear inspection movements along an inspection direction (Z);
detect the interruption or the non-interruption of the light beam in the course of
said linear inspection movements along the inspection direction, and
consequently selecting a subsequent inspection position at which a subsequent
linear inspection movement is performed;
stop the sequence of checking displacements at a final inspection position of the
light beam along said at least one checking direction that lies at a distance less
than a preset value from a previous inspection position, where, in the course of
linear inspection movements at said final inspection position and said previous
inspection position, there have been detected the interruption and the non-
interruption of the light beam, respectively, or vice versa, and identify the position
of the tool along the checking direction on the basis of said final inspection
position.

Documents:

00883-kolnp-2006 drawings.pdf

00883-kolnp-2006-abstract.pdf

00883-kolnp-2006-claims.pdf

00883-kolnp-2006-correspondence others.pdf

00883-kolnp-2006-cover letter.pdf

00883-kolnp-2006-description complete.pdf

00883-kolnp-2006-form 1.pdf

00883-kolnp-2006-form 2.pdf

00883-kolnp-2006-form 3.pdf

00883-kolnp-2006-form 5.pdf

00883-kolnp-2006-form-26.pdf

00883-kolnp-2006-international publication.pdf

00883-kolnp-2006-international search authority report.pdf

00883-kolnp-2006-pct form.pdf

00883-kolnp-2006-priority document-1.1.pdf

00883-kolnp-2006-priority document.pdf

883-KOLNP-2006-(27-08-2012)-CORRESPONDENCE.pdf

883-KOLNP-2006-(27-08-2012)-FORM-13.pdf

883-KOLNP-2006-(27-08-2012)-FORM-16.pdf

883-KOLNP-2006-(27-08-2012)-OTHERS.pdf

883-KOLNP-2006-(27-08-2012)-PA-CERTIFIED COPIES.pdf

883-KOLNP-2006-ABSTRACT.pdf

883-KOLNP-2006-AMANDED CLAIMS.pdf

883-KOLNP-2006-AMENDED PAGE OF SPECIFICATION.pdf

883-kolnp-2006-correspondence.pdf

883-KOLNP-2006-DESCRIPTION (COMPLETE).pdf

883-KOLNP-2006-DRAWINGS.pdf

883-kolnp-2006-examination report.pdf

883-KOLNP-2006-FORM 1.pdf

883-kolnp-2006-form 18.pdf

883-KOLNP-2006-FORM 2.pdf

883-kolnp-2006-form 26.pdf

883-kolnp-2006-form 3-1.1.pdf

883-KOLNP-2006-FORM 3.pdf

883-kolnp-2006-form 5.pdf

883-kolnp-2006-granted-abstract.pdf

883-kolnp-2006-granted-claims.pdf

883-kolnp-2006-granted-description (complete).pdf

883-kolnp-2006-granted-drawings.pdf

883-kolnp-2006-granted-form 1.pdf

883-kolnp-2006-granted-form 2.pdf

883-kolnp-2006-granted-specification.pdf

883-kolnp-2006-others-1.1.pdf

883-KOLNP-2006-OTHERS.pdf

883-KOLNP-2006-PETITION UNDER RULE 137.pdf

883-kolnp-2006-reply to examination report-1.1.pdf

883-KOLNP-2006-REPLY TO EXAMINATION REPORT.pdf

abstract-00883-kolnp-2006.jpg


Patent Number 247782
Indian Patent Application Number 883/KOLNP/2006
PG Journal Number 20/2011
Publication Date 20-May-2011
Grant Date 18-May-2011
Date of Filing 10-Apr-2006
Name of Patentee MARPOSS SOCIETA PER AZIONI
Applicant Address VIA SALICETO, 13, 40010 BENTIVOGLIO, BO
Inventors:
# Inventor's Name Inventor's Address
1 TURRINI ANDREA VIA BAROZZI, 6, 40126 BOLOGNA
PCT International Classification Number B23Q17/22; B23Q17/24
PCT International Application Number PCT/EP2004/010202
PCT International Filing date 2004-09-13
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 BO2003A000536 2003-09-16 Italy