CİVAN, Ahmet (Osb 75. Yil Bulvari, Bursa, 16140, TR)
| CLAIMS 1. An opto-electronic based contactless bending angle measurement mechanism (20) characterized by comprising at least one pair of distance measuring sensors (28) which are connected to each other so as to displace together and which have at least one ray supply (281) each sending laser ray (30) to the work piece (40), at least one optical receiver (282) which receives the laser ray (30) which provided from said ray supply (281) and which reflects from the work piece (40) and a processor unit which produces the distance information with respect to the signal provided by the optical receiver (282); a sensor movement mechanism in order to move said couple of distance measuring sensor (28); a main control unit which compares the distance data provided by the processor unit of the two distance measuring sensors (28) and accordingly, which provides the sensor movement mechanism to displace the distance measuring sensors (28) along the bending so that the laser rays (30) reach the work piece (40) substantially perpendicular and an angle measuring device which detects and measures the movement amount of said distance measuring sensors (28). 2. A bending angle measurement mechanism (20) according to Claim 1 , wherein the main control unit provides a pair of distance measuring sensors (28) to displace so that the sensors are substantially parallel to the work piece (40) along the bending. 3. A bending angle measurement mechanism (20) according to Claim 2, wherein a couple of said distance measuring sensors (28) are connected adjacent to each other so that the ray supplies (281) and the optical receivers (282) are in the same alignment and accordingly, the main control unit provides the distance measuring sensor (28) to displace along the bending until the distance information provided by the optical receiver (282) of a distance measuring sensor (28) is the same as the distance information of the optical receiver (282) of the other sensor. 4. A bending angle measurement mechanism (20) according to any of the preceding claims, wherein said sensor displacement mechanism is an arm mechanism which moves the distance measuring sensor (28) along an arc. 5. A bending angle measurement mechanism (20) according to any of the claims between 1 and 4, wherein said sensor displacement mechanism rotates the distance measuring sensor (28) around itself. 6. A bending angle measurement mechanism (20) according to Claim 4, said arm mechanism comprises a carrier arm (27) to whose end a distance measuring sensor (28) is connected and an electrical motor (24) which rotates said carrier arm (27) with respect to the electrical signals it acquires from said control unit. 7. A bending angle measurement mechanism (20) according to Claim 1, wherein said angle measuring device measures the rotation amount of said electrical motor (24). 8. A bending angle measurement mechanism (20) according to Claim 1, wherein said electrical motor is a step motor comprising also a motor driver circuit communicating with the main control unit. 9. A bending angle measurement mechanism (20) according to Claim 1 or 7, wherein said angle measuring device is an encoder (25) connected to the shaft of the electrical motor (24). 10. A bending angle measurement mechanism (20) according to any of the preceding claims, the distance measuring sensor (28), sensor displacement mechanism and angle measuring device comprise a carrier body whereon the bending machine is placed and which is connected to the main body thereof. 11. A bending angle measurement mechanism (20) according to Claim 1 or 10, wherein the distance measuring sensor (28) comprises a guide mechanism which provides bringing closer and moving away of sensor displacement mechanism and angle measuring device to the body of the big machine and which is embodied on said carrier body. 12. A bending angle measurement mechanism (20) according to Claim 11, wherein said carrier body is connected to the lateral lower alignment of the lower mould (16) of the bending machine. 13. An opto-electronic based contactless bending angle measurement method, characterized by comprising the steps of: a) providing at least one couple of distance measuring sensors (28) which are connected to each other so as to displace together and which have at least one ray supply (281); at least one optical receiver (282) which receives the laser ray (30) provided by said ray supply (281) and reflecting from a work piece (40) and a processor unit which produces the distance information with respect to the signal provided by the optical receiver (282), b) positioning said couple of distance measuring sensors (28) at a certain distance to the work piece (40) placed into the bending machine, c) determining the distance between the sensor and the work piece (40) by operating the first distance sensor, d) determining the distance between the sensor and the work piece (40) by operating the second distance sensor, e) comparing the distance data provided by the two distance measuring sensors (28) and thus, determining the extension direction of the distance measuring sensors (28) with respect to the work piece (40), f) moving the distance measuring sensors (28) together until the laser rays (30) provided by the ray supplies (281) arrive substantially perpendicularly to the work piece (40) with respect to the extension direction detected, g) obtaining the bending angle of the work piece (40) by determining the displacement amount of the distance measuring sensors (28) by means of an angle measuring device. 14. A method according to Claim 13, wherein in said step (a), said couple of distance measuring sensors (28) is connected so as to be adjacent to each other so that ray supplies (281) and optical receivers (282) and transmitters are in the same alignment. 15. A method according to Claim 13, wherein in said step (b), bending angle measurement mechanism (20) is connected to the machine (10) body at a region below the lower mould (16) of the bending machine. 16. A method according to Claim 13 or 15, wherein in said step (b), at least two bending angle measurement mechanisms (20) are connected from two mutual lateral parts to the machine body (10) below the lower mould (16) of the bending machine. 17. A method according to Claim 13, wherein in said step (b), the distance between the bending angle measuring mechanism (20) and the machine body (10) can be changed and adjusted prior to the bending process with respect to the structural characteristics of the bending machine and the position of the lower mould (16). 18. A method according to Claim 13, wherein in said step (f), the distance measuring sensors (28) can be displaced together along the bending until the distance information provided by the optical receiver (282) of a distance measuring sensor (28) is the same as the value of the optical receiver (282) of the other sensor (28). 19. A method according to Claim 13 or 18, wherein in said step (f), the distance measuring sensors (28) are displaced along an arc. 20. A method according to Claim 13, wherein in said step (f), the distance measuring sensors (28) are rotated around themselves. 21. A method according to Claim 13, wherein prior to said step (b), a reference work piece (40) manufactured particularly so as to have a surface which is not rough and which does not have any deflection thereon is positioned on the lower mould (16) and afterwards, referencing is realized by applying at least the steps between step b and step f. 22. A method according to Claim 21 , wherein in said step (b), when the work piece (40) to be bent is placed into the bending machine, during said referencing process, the obtained distance values are compared with that values, thus the deflection amount of the work piece (40) is determined from the difference between the values. 23. A method according to Claim 13, wherein just after the bending process ends and after the movable upper mould (15) of the bending machine is substantially separated from the piece, the steps between step c and step g are realized, and from the difference between the two obtained values, the back springing values of the work piece (40) are obtained. |
The present invention relates to bending angle measurement mechanisms used in bending machines and particularly relates to bending angle measurement mechanisms realizing optoelectronic based contactless measurement.
PRIOR ART
In machines like press brake which changes the form of metal, in order to provide bending in a controlled and correct manner, the bending angle of the work piece has to be detected and determined. The most frequent embodiments on this subject are the optoelectronic based contactless bending angle measurement mechanisms.
Accordingly, in the patent US4564765, one and two laser ray beams provided by one or two laser light supply are sent to the surface to be bent at a perpendicular angle and thus, one or more ray points are obtained on the work piece. Afterwards, the displacement of the ray points on the work piece between the start and stop of the bending is detected by means of a photo-detector like a diode camera positioned perpendicularly to the light points and thus the bending angle can be calculated. In summary, the fundamental of the system is the interpretation of the images obtained by a camera by means of an image processing technique, thus this system is extremely expensive.
In the patent WO9730327, an embodiment where no camera and image processing method is used is disclosed. Accordingly, the measurement light provided by the light supply is sent to the work piece while the angle sensor is partially rotated forwardly and backwardly around itself. On the angle sensor, there is a plurality of optical sensors positioned symmetrically with respect to said light supply in order to receive the light reflected from the work piece. Accordingly, the intensity of the received light is correlated with the rotation angle of the angle sensor and an angle calculation unit calculates the bending angle of the work piece based on the peak value of the received light intensity and the rotation angle corresponding to this peak value of the angle sensor. As can be understood, in this system, the laser ray is not applied to the surface of the work piece completely perpendicularly and this condition leads to erroneous measurement particularly in case the surface of the work piece is rough. Moreover, particularly manufactured angle sensors measuring the light intensity also increase the cost of this system seriously.
As a result, because of the abovementioned drawbacks, a novelty is required in the related technical field.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to a novel bending angle measurement mechanism that eliminates above mentioned disadvantages and brings new advantages to the relevant technical field.
An object of the subject matter invention is to provide a bending angle measurement mechanism which can realize flawless angle measurement in work pieces with brilliant and/or rough surfaces since the subject matter invention can apply the laser ray to the work piece in a perpendicular manner continuously.
Another object of the subject matter invention is to provide a bending angle measurement mechanism which has a much lower cost than similar mechanisms and which can realize flawless measurement with the distance sensors which measures ray distance instead of ray intensity and which thus uses angle sensors which measure light intensity.
Another object of the invention is to provide a bending angle measurement mechanism which can be easily adapted for usage with different bending moulds in different machines or in the same machine, thanks to the adjustment of the position thereof with respect to the machine.
In order to realize all of the objects obtained from the above explanation and the below mentioned detailed explanation, the present invention is an opto-electronic based contactless bending angle measurement mechanism characterized by comprising at least one pair of distance measuring sensors which are connected to each other so as to displace together and which have at least one ray supply each sending laser ray to the work piece, at least one optical receiver which receives the laser ray provided from said ray supply and which reflects from the work piece and a processor unit which produces the distance information with respect to the signal provided by the optical receiver; a sensor movement mechanism in order to move said couple of distance measuring sensors; a main control unit which compares the distance data provided by the processor unit of the two distance measuring sensors and accordingly, which provides the sensor movement mechanism to displace the distance measuring sensors along the bending so that the laser rays reach the work piece substantially perpendicular and an angle measuring device which detects and measures the movement amount of said distance measuring sensors.
In a preferred embodiment of the present invention, the main control unit provides a pair of distance measuring sensors to displace so that the sensors are substantially parallel to the work piece along the bending.
In another preferred embodiment of the present invention, a couple of said distance measuring sensors are connected adjacent to each other so that the optical receivers and transmitters thereof are in the same alignment and accordingly, the control unit provides the distance measuring sensor to displace along the bending until the distance information provided by the optical receiver of a distance measuring sensor is the same as the distance information of the optical receiver of the other sensor. Because when the distance information provided by two optical receivers is the same, this illustrates that the distance measuring sensor is parallel to the work piece.
In another preferred embodiment of the present invention, said sensor displacement mechanism is an arm mechanism which moves the distance measuring sensor along an arc.
In another preferred embodiment of the present invention, said arm mechanism comprises a carrier arm to whose end a distance measuring sensor is connected and an electrical motor which rotates said carrier arm with respect to the electrical signals it gets from said control unit.
In another preferred embodiment of the present invention, said angle measuring device measures the rotation amount of said electrical motor.
In another preferred embodiment of the present invention, said electrical motor is a step motor comprising also a motor driver circuit communicating with the control unit. In another preferred embodiment of the present invention, said angle measuring device is an encoder connected to the shaft of the electrical motor. Thus, without a need for an additional calculation process, the rotation amount of the motor, thus the bending angle of the work piece can be measured real time.
In another preferred embodiment of the present invention, the distance measurement sensor, sensor displacement mechanism and angle measuring device comprise a carrier body whereon the bending machine is placed and which is connected to the main body thereof.
In another preferred embodiment of the present invention, the distance measuring sensor comprises a guide mechanism which provides the bringing closer and moving away of sensor displacement mechanism and angle measuring device to the body of the big machine and which is embodied on said carrier body.
In another preferred embodiment of the present invention, said carrier body is connected to the lateral lower alignment of the lower mould of the bending machine.
In order to realize all of the objects obtained from the above explanation and the below mentioned detailed explanation, the present invention is also an opto-electronic based contactless bending angle measurement method, characterized by comprising the steps of: a) providing at least one couple of distance measuring sensors which are connected to each other so as to displace together and which have at least one ray supply; at least one optical receiver which receives the laser ray provided from said ray supply and reflecting from a work piece and a processor unit which produces the distance information with respect to the signal provided by the optical receiver,
b) positioning said couple of distance measuring sensors at a certain distance to the work piece placed into the bending machine,
c) determining the distance between the sensor and the work piece by operating the first distance sensor,
d) determining the distance between the sensor and the work piece by operating the second distance sensor, e) comparing the distance data provided by the two distance measuring sensors and thus, determining the extension direction of the distance measuring sensors with respect to the work piece,
f) moving the distance measuring sensors together until the laser rays provided from the ray supplies arrive substantially perpendicularly to the work piece with respect to the extension direction detected,
g) obtaining the bending angle of the work piece by determining the displacement amount of the distance measuring sensors by means of an angle measuring device.
In a preferred application of the subject matter method, in said step (a), said couple of distance measuring sensors is connected so as to be adjacent to each other so that ray supplies and optical receivers and transmitters are in the same alignment.
In a preferred application of the subject matter method, in said step (b), bending angle measurement mechanism is connected to the machine body at a region below the lower mould of the bending machine.
In a preferred application of the subject matter method, in said step (b), at least two bending angle measurement mechanisms are connected from two mutual lateral parts to the machine body below the lower mould of the bending machine.
In a preferred application of the subject matter method, in said step (b), the distance between the bending angle measuring mechanism and the machine body can be changed and adjusted prior to the bending process with respect to the structural characteristics of the bending machine and the position of the lower mould.
In a preferred application of the subject matter method, in said step (f), the distance measuring sensors can be displaced together along the bending until the distance information provided by the optical receiver of a distance measuring sensor is the same as the value provided by the optical receiver of the other sensor.
In a preferred application of the subject matter method, in said step (f), the distance measuring sensors are displaced along an arc. In a preferred application of the subject matter method, in said step (f), the distance measuring sensors are rotated around themselves.
In a preferred application of the subject matter method, prior to said step (b), a reference work piece manufactured particularly so as to have a surface which is not rough and which does not have any deflection thereon is positioned on the lower mould and afterwards, referencing is realized by applying at least the steps between step b and step f.
In a preferred application of the subject matter method, in said step (b), when the work piece to be bent is placed into the bending machine, during said referencing process, the obtained distance values are compared with that values, thus the deflection amount of the work piece is determined from the difference between the values.
In another preferred application of the subject matter method, just after the bending process ends and after the movable upper mould of the bending machine is substantially separated from the piece, the steps between step c and step g are realized, and from the difference between the two obtained values, the back springing values of the work piece are obtained.
The structural and the characteristic features and all the advantages of the subject matter invention can be understood more precisely by means of the detailed explanation which is written with references to these figures and therefore, it had to be evaluated with the detailed explanation and figures that are explained below.
BRIEF DESCRIPTION OF THE FIGURES
In Figure 1 , the representative view of the press brake to which the subject matter angle measuring mechanism is applied is given.
In Figure 2, the perspective view of the subject matter angle measuring mechanism is given.
In Figure 3a and 3b, the representative operation style of the subject matter angle measuring mechanism applied to a press brake is given. REFERENCE NUMBERS
10 Machine body
11 Intermediate body
12 Drive group
13 Hydraulic cylinder group
14 Control panel
15 Upper mould
16 Lower mould
17 Lower mould holder
20 Angle measuring mechanism
21 Carrier table
22 Connection plate
23 Guides
231 Guide car
232 Stopping plate
233 Plastic stop
24 Motor
241 Motor connection table
25 Encoder
251 Coupling
26 Counter weight
261 Weight pin
27 Carrier arm
271 Connection plate
272 Conical fastening coupling
28 Distance measuring sensor
281 Ray supply
282 Optical receiver
283 Lens
29 Locking plate
291 Locking screw
30 Laser ray
40 Work piece
THE DETAILED DESCRIPTION OF THE INVENTION In this detailed explanation, the subject matter novelty is explained with examples in order to make the subject more understandable without forming any restrictive effect. Accordingly, in this detailed explanation, the subject matter invention is explained to be applied to a press brake. However, the invention can be adapted to any processing machine which changes the form of the work pieces (40).
With reference to Figure 1 , the press brake to which the subject matter bending angle measuring mechanism is adapted has a machine body (10) similar to C shape. On the upper part of the machine body (10), there are the drive group (12) and the hydraulic cylinder group (13) providing the upper mould (15) to displace upwardly and downwardly with a certain force. There is the lower mould (16) at the lower alignment of the upper mould (15), onto which the work piece (40) to be bent is placed. The lower mould (16) is fixed onto a lower mould holder (17). The lower mould holder (17) is placed onto an intermediate body (11) connected to the lower lateral surface of the machine body (10). Again from this figure, the control panel (14) of the machine can also be seen. Again with reference to Figure 1 , in this preferred embodiment, two subject matter bending angle measuring mechanisms (20) are connected symmetrically to two sides of the intermediate body (11). Thus, the confirmation of the values whose angle measurement will be realized can be realized firmly from two different points.
With reference to Figure 2, the subject matter angle measuring mechanism (20) essentially comprises a carrier body; a couple of distance measuring sensors (28) which are positioned on said carrier body and which are positioned adjacent to each other and which are positioned so as to displace together; an arm mechanism which moves said distance measuring sensors (28) along an arc and guides (23) whereon said arm mechanism is placed by means of a guide car (231) and which thus provides the bringing closer and moving away of the arm mechanism and the distance measuring sensors (28) connected to it in a horizontal direction to the machine body (10). Moreover, in the subject matter invention, there is a main control unit which moves the arm mechanism with respect to the data obtained at least from the distance measuring sensors (28) and which can realize some other sub-functions.
In more details, said carrier body comprises a carrier table (21) whereon the arm mechanism is placed and which extends horizontally with respect to the ground and a connection plate (22) which fixes said carrier table (21) to the intermediate body (11) of the machine and which extends orthogonally to the ground. Said arm mechanism comprises a carrier arm (27) to whose one end a couple of distance measuring sensor (28) are connected through a connection plate (271), and a step motor (24) comprising a motor driver circuit which communicates with the main control unit and whose shaft is connected to said carrier arm (27) by means of a conical fastening coupling (272). Said motor driver circuit is a micro step motor driver which preferably has Sanyo Denki trademark, which is PMM-MD-23120-10 model and which can operate at DC 24 V/36 V. On the other hand, the arm mechanism is on a motor connection table (241) with preferably U cross-section and the motor connection table (241) is placed onto said guides (23) through a guide car (231). In an alternative embodiment of the subject matter invention, there is also a height adjustment mechanism which provides the adjustment of the height of the distance measuring sensors (28).
Said carrier arm (27) has a long rectangular form and there is a couple of apertures similar to U form which is slanted and elongated. The carrier arm (27) is connected preferably from the middle region of the shaft of the step motor (24) and there are the distance measuring sensors (28) on one end of the motor (24) shaft, and a counter weight (26) is connected to the other end thereof through a weight pin (261). Thanks to said counterweight (26), the step motor (24) operates in a more stabile manner. In an alternative embodiment, the need for a counterweight (26) can be eliminated provided that a suitable step motor (24) is used. An encoder (25) is connected to the other end of the step motor (24) through a coupling (251), thus the rotation amount of the step motor (24) can be measured in real time by means of the encoder (25). In the subject matter invention, preferably an encoder (25) of the H series of Hohner is used.
Preferably two guides (23) extend longitudinally on the carrier body and thanks to this, the arm mechanism can be displaced forwardly and backwardly on the carrier body. There is a plastic stop (233) at the connection plate (22) end of the guide line and there is a guide car (231) stopping plate (232) behind this stop. The fixation of the arm mechanism on the guides (23) is provided by means of a locking plate (29) and a locking screw (291) which is stud upon to the motor connection table (241) after it passes through this plate. Said locking plate (29) is preferably a metal piece which extends longitudinally along the carrier body and which has an aperture similar to an lengthened ellipse thereon. Accordingly, the locking screw (291) passes through this aperture and reaches the motor connection table (241), as a result of screwing, the screw head leans against the locking plate (29) and thus thanks to the friction, the movement of the arm mechanism on the guide is prevented. On the other hand, in alternative embodiments, different locking mechanisms can also be used.
Each of the distance measuring sensors (28) which is one of the critical members of the subject matter invention preferably has a body similar to a rectangular prism. There is an optical receiver (282) on the short edge side of said body and there is a ray supply (281) which is positioned symmetrically on the other short edge side. The optical receiver (282) comprises a PSD (position sensitive detector) which produces an electrical signal with respect to the reaching point of the ray and this signal is converted to a voltage value which will be a reference to the distance by means of the processor unit of the distance sensor or this signal is converted directly to a distance value. In more details, PSDs comprise a plurality of photo-receivers embodied as a sequence thereon, thus, whichever photo-receiver the ray falls on, said processor unit special to it produces a voltage value and this value is converted into distance value by the own processor unit of the distance measuring sensor (28) or by the main control unit of the angle measuring mechanism (20). Related to this, there is a lens (283) which makes a ray point by collecting the distributed light reflected from the work piece (40) on PSD and thanks to this, which provides the ray to reach the photo-receivers in the form of a point. In the subject matter invention, preferably Laser Distance Sensors with trademark MEL ® are used.
In an alternative embodiment of the subject matter invention, a particularly made distance laser comprising a couple of ray supplies (281) and a couple of optical receivers (282) can also be used. In another alternative embodiment, distance measuring sensors (28) can be displaced preferably synchronized and adjacent to each other and even if it is an expensive solution, they can be displaced synchronized and independent of each other.
Under the light of the structural details and under the light of Figure 3a and 3b, the operation and usage of an example embodiment of the subject matter invention is as follows.
The work piece (40) to be bent is placed on the lower mould (16) and the subject matter bending angle measuring mechanism (20) is activated. Thus, the laser ray (30) provided by the own ray supply (281) of each distance measuring sensor (28) hits the work piece (40) and reaches the related optical receiver (282) which is at the opposite side thereof, optical receivers (282) produce an electrical signal with respect to the reaching point of the ray thereon. If the signals in the two optical receivers (282) are different from each other, in this case, the main control unit detects that the distance measuring sensor (28) is not parallel to the work piece (40) and it communicates with the motor driver circuit in the arm mechanism and it starts rotating the carrier arm (27). During rotation, the main control unit continuously communicates with the processor unit of the distance measuring sensor (28), here it compares the values provided by two optical receivers (282) and thanks to this, it continues the rotation process until two said values are equal to each other. When the values are equal, the main control unit understands that the distance measuring sensor (28) is substantially parallel to the work piece (40) and it stops the rotation process. Thus, the distance measuring sensor (28) moves along an arc whose length is determined by the distance between the carrier arm (27) and the motor (24) shaft. During this movement, the encoder (25) measures the rotation angle of the step motor (24), thus the angle between the horizontal position and the final position of the distance measuring sensors (28) can be detected flawlessly without the need for an additional calculation, this value naturally gives the bending angle of the sheet.
In a preferred application of the subject matter invention, prior to the abovementioned bending process, the referencing process is realized. In this process step, a reference sheet which is particularly manufactured on the lower mould (16) of the bending machine and which does not have a deflection and a roughness on the surface thereof is placed onto the lower mould (16), afterwards, the subject matter bending angle measuring mechanism (20) is activated and the distance measuring sensors (28) are made parallel to the reference sheet in the abovementioned manner. The distance values of this reference point provided by optical receivers (282) are recorded to a memory unit. Accordingly, when a work piece (40) whose bending will be realized is placed onto the lower mould (16), if this work piece (40) has a deflection, the measured distance values will be compared with the distance values in the referencing process and the deflection of the work piece (40) is determined and prior to the bending process, the distance measuring sensor (28) is made parallel to the work piece (40) with respect to this deflection value.
Again in another preferred application of the subject matter invention, the distance values regarding the instant the bending process ends and regarding the instant the upper mould (15) lifts some amount above the lower mould (16) after the bending process ends are recorded. Since, after the bending process, at the instant when the upper mould (15) lifts, the work pieces (40) realize a back springing movement called spring back and as a result of this, the bending angle can change even if the change is small. Thanks to this process, the difference between the distance values regarding the bending ending instant and regarding the instant after a while the upper mould (15) lifts reflect the spring back characteristics of the work piece (40), thus, these obtained values form a reference for the following bending processes.
In an alternative embodiment of the subject matter invention, the distance measuring sensor (28) can be rotated around itself instead of being moved along an arc. In this case, a guide mechanism providing the adjustment of the orthogonal height of the distance sensor (28) can be adapted to the subject matter invention.
The protection scope of the present invention is set forth in the annexed Claims and cannot be restricted to the illustrative disclosures given above, under the detailed description. It is because a person skilled in the relevant art can obviously produce similar embodiments under the light of the foregoing disclosures, without departing from the main principles of the present invention.
Next Patent: A DISTANCE MEASURING LASER SENSOR WITH DIGITAL BASED FEEDBACK CAPABILITY