Safety device for a machine and operating method

Abstract

Production and work machines are to be able to be more safely operated. Thereto, they can be equipped with a safety device, which comprises a light curtain, a first and a second reflection device, which are each formed for reflecting light of the light curtain, and a first identification element integrated in the first reflection device as well as a second identification element integrated in the second reflection device. Moreover, the safety device comprises a first sensor device and a second sensor device for reading out the identification elements. A control device provides a start signal for the machine only if the first sensor device reads out the first identification information and the second sensor device reads out the second identification information at the same time.

Claims

1. A safety device for a machine, the safety device comprising: a light curtain, a first and a second reflection device, which are each formed for reflecting light of the light curtain, a first identification element integrated in the first reflection device and a second identification element integrated in the second reflection device, a first sensor device for reading first identification information of the first identification element out of the first reflection device, a second sensor device for reading second identification information of the second identification element out of the second reflection device, and a control device for providing a start signal for the machine only if the first sensor device reads out the first identification information and the second sensor device reads out the second identification information at the same time and for providing a stop signal for the machine as soon as the light curtain detects its light reflected by one of the reflection devices.

2. The safety device according to claim 1, wherein the start signal is provided by the control device only if the first and the second identification information each correspond to preset reference information.

3. The safety device according to claim 1, wherein a line laser device is oriented parallel to the light curtain with its beam direction.

4. The safety device according to claim 1, wherein the first and the second reflection device are each formed for wearing at a limb of an operator of the machine.

5. The safety device according to claim 4, wherein the reflection devices are each formed as a glove, finger ring or bracelet.

6. The safety device according to claim 5, wherein each glove or each bracelet is respectively equipped with an expansion sensor, tension sensor, pulse tracker or vein detector, the signals of which are also a required condition for the control device in order that the start signal is provided.

7. The safety device according to claim 1, wherein the light curtain is realized with infrared light technology and the reflection devices are adapted thereto.

8. The safety device according to claim 1, wherein a third sensor device for examining a reflecting capacity of the first reflection device is arranged immediately next to the first sensor device and a fourth sensor device for examining a reflecting capacity of the second reflection device is arranged immediately next to the second sensor device.

9. The safety device according to claim 1, wherein the first sensor device, the second sensor device, the first identification element and the second identification element are based on RFID technology.

10. The safety device according to claim 1, wherein each detection event of the light curtain is countable by the control device and a corresponding counting result is taken into account in providing the start signal.

11. The safety device according to claim 1, wherein the safety device comprises a reflection element, which is movable into a beam path of the light curtain for examination purposes.

12. A machine with a safety device, the safety device comprising: a light curtain, a first and a second reflection device, which are each formed for reflecting light of the light curtain, a first identification element integrated in the first reflection device and a second identification element integrated in the second reflection device, a first sensor device for reading first identification information of the first identification element out of the first reflection device, a second sensor device for reading second identification information of the second identification element out of the second reflection device, and a control device for providing a start signal for the machine only if the first sensor device reads out the first identification information and the second sensor device reads out the second identification information at the same time and for providing a stop signal for the machine as soon as the light curtain detects its light reflected by one of the reflection devices; wherein a protection area of the machine is monitored by the light curtain.

13. The machine according to claim 12, wherein the first and the second sensor device are arranged at least 20 cm apart from each other.

14. The machine according to claim 12, wherein the protection area of the machine is indicated by a line laser with visible light on an operationally provided operator side.

15. The machine according to claim 12, which is formed as a rolling machine, punching machine, pressing machine or machine tool.

16. A method for operating a machine comprising: illuminating a border of a protection area of the machine with a light curtain, providing a first reflection device and a second reflection device, wherein a first identification element is integrated in the first reflection device and a second identification element is integrated in the second reflection device, reading first identification information of the first identification element out of the first reflection device by a first sensor device, reading second identification information of the second identification element out of the second reflection device by a second sensor device different from the first sensor device, detecting light of the light curtain after reflection on one of the reflection devices, and providing at least one of: a start signal for the machine only if reading out the first identification information and reading out the second identification information are effected at the same time, and a stop signal for the machine as soon as the detection of the light is effected.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Now, the present invention is explained in more detail based on the attached drawings, which illustrate as follows:

(2) FIG. 1 shows a rolling machine with safety device in a start phase;

(3) FIG. 2 shows a detailed view of the rolling machine in an operating phase;

(4) FIG. 3 shows a detailed view of the rolling machine in another operating phase; and

(5) FIG. 4 shows a punching machine with safety device according to the invention.

(6) The embodiments described in more detail below present preferred embodiments of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) In the present case, the rolling machine illustrated in FIG. 1 comprises two rollers 1. An operator not illustrated can introduce rolling material from above between these rollers 1. In order that the operator and in particular his hands are not endangered, the rolling machine comprises a safety device 2. It is in particular located above the nip such that this area around the nip can be secured (safety area). The safety device 2 for example comprises a rack 3, which can be realized as a cuboid frame rack. The rack 3 is preferably arranged on a housing 4 of the rolling machine.

(8) The safety device 2 comprises a light curtain 5, which can be attached to the rack 3, in particular parallel to the rollers 1. The light curtain 5 typically comprises a linear arrangement of numerous reflection light barriers. Beneficially, they are operated in the infrared range of the light. The light sources of these reflection light barriers preferably provide parallel light beams 6 in the switched-on state, which diverge as little as possible. By the plurality of identical parallel linearly offset light beams 6, a curtain-like radiation field results. If a reflecting object gets into this curtain-like radiation field, the light is reflected back to one or more receivers of the light curtain 5 and a corresponding detection signal can be obtained. This detection signal can for example be used in a control device, which can be integrated in the housing 4 of the rolling machine, to switch off the rolling machine.

(9) In the present example, the rolling machine also comprises a similar light curtain 5 at the rear roller (not visible in the figure) in FIG. 1, which also produces beams 6.

(10) Since the light curtain is usually based on infrared technology, the radiation field cannot be perceived by the operator. For this reason, the safety device 2 is here additionally equipped with a line laser device, which can be integrated in the light curtain 5. This line laser device generates a laser radiation field 7 in the operation, which results in a laser line upon impinging on an object. Beneficially, this laser curtain, i.e. the laser radiation field 7, extends exactly parallel to the light curtain 5 with the beams 6. A similar laser curtain 7 can in turn be located on the rear side of the rolling machine if an operation of the rolling machine from the rear side is also possible.

(11) Two reflection devices 8 and 8′ also belong to the safety device 2, which here each have the shape of a bracelet. For guidance, the hands 9 and 9′ of an operator are also drawn in FIG. 1 to better understand the wearing position of the reflection devices 8 and 8′. The reflection devices 8, 8′ each comprise an identification element with identification information. The identification element is preferably an RFID element or else another, code carrying element such as for instance a QR code or barcode.

(12) In addition, the safety device also comprises two sensor devices 10 and 10′. Here, both sensor devices are attached to the housing 4 of the rolling machine on the front operating side. The first sensor device 10 to a left leg of the housing 4 and the second sensor device 10′ to a right leg of the housing 4. The first sensor device 10 can read first identification information of the first identification element out of the first reflection device 8 and the second reflection device 10′ can read second identification information of the second identification element out of the second reflection device 8′. Only if both identification information are read out of the two reflection devices 8 and 8′ at the same time, the control device of the machine and in particular of the rolling machine determines it such that the control device can generate a start signal for the machine. Thereby, the rollers 1 can begin to run. In this manner, it can be ensured that the operator wears the reflection devices 8 and 8′, respectively, at the same time when he operates the machine.

(13) FIG. 2 shows an operating phase of the rolling machine while it runs. The operator reaches below the roller 1, which is symbolized by the two hands 9 and 9′. This area below the roller 1 is uncritical and is therefore not monitored by the safety device 2 and the light curtain 5 with the beams 6, respectively. In this position, the operator can for example remove rolled material from the rolling machine.

(14) In the present example, the safety device 2 comprises a plate-shaped reflector element 11 on a linear slide 12 extending parallel to the light curtains 5. The reflector element 11 is movable along the linear slide 12. It reflects the infrared light of the light curtain 5. Thereby, it can serve for examining the light curtain 5 before machine start.

(15) Here, the light curtain and its beam field with the beams 6, respectively, are slightly outwards inclined. However, the orientation of the light curtain 5 can be arbitrarily chosen. Optionally, it can also be perpendicular or inwards inclined. However, it is of particular advantage if the line laser or laser beam field 7 extends as parallel to the beam field of the light curtain 5 as possible. Thereby, the visible light of the laser beam field 7 can always indicate the position of the beam field of the light curtain 5 inherently invisible to the operator.

(16) The sensor devices 10, 10′ can each be combined sensor devices (first and third sensor devices and second and fourth sensor devices, respectively), by which not only the respective identification information of the reflection devices 8, 8′ is read out, but also the reflecting capacities (intensity of a reflected signal) of the reflection devices 8, 8′ can be measured. In FIG. 2, this combined sensor system is indicated in that each housing of the sensor devices 10, 10′ comprises two windows.

(17) FIG. 3 shows a further operating phase of the rolling machine. Here, the operator has to reach into a safety area above the rollers 1 to for example insert a billet into the rolling machine. The safety area is bounded to the bottom by the rollers 1 and laterally by the beam fields of the light curtains 5, which are indicated by the beams 6. As is apparent from FIG. 3, the fingers of the operator already reach through the beam field of the light curtain 5. However, this is still an uncritical situation since the fingers cannot yet be captured by the rollers 1. The fingers and the hands of the operator, respectively, barely reflect the infrared light such that the light curtain 5 does not respond to the penetration of the fingers through the beam field. However, the operator here respectively wears bracelets 8 and 8′, respectively, at the wrists. They distinctively reflect the infrared light such that the light curtain 5 would register the penetration thereof into the safety area. In order that the operator can better recognize when the bracelets 8, 8′ reach the safety area and the beam field of the light curtain 5, respectively, the line laser (line laser field 7; cf. FIGS. 1 and 2) not drawn in FIG. 3 marks the penetration edge of the hands 9, 9′ through the beam field of the light curtain 5.

(18) FIG. 4 shows a further embodiment for the safety device 2 according to the invention. Here, it is integrated in a press or pressing machine, in particular on the operating portal thereof. The operating portal is “closed” by the light curtain 5 with its beams 6. Here, the curtain-like line laser field 7 also extends parallel to the radiation field of the light curtain 5. Both fields are preferably again congruent such that the line laser field 7 optically indicates the radiation field of the light curtain 5. If the operator reaches into the light curtain 5 with his hands 9 without the infrared light reflecting reflection bracelets 8, 8′ penetrating into the light curtain 5, thus, the press continues to run. Otherwise, when the reflection devices or reflection bracelets 8, 8′ penetrate into the light curtain 5, the press immediately stops. For examining the functionality of the light curtain, the safety device here comprises a foldable reflection element 13. With folded reflection element, all of the reflection light barriers of the light curtain 5 can be examined at the beginning of the operation.

(19) Thus, corresponding to the present invention, an intervention protection based on an invisible reflection light curtain can be provided in a specific embodiment, which avoids unintended trigger by the not securely recognizable trigger area of the protection field or protection area and ensures the correct use of the trigger elements like reflection bracelets, reflection gloves etc. (reflection devices). The visibility of the protection or trigger area is realized by the integration of a line laser with a laser projection line, which extends identically to the trigger function of the light curtain. The maximum deviation is for example only few millimeters (e.g. 5 mm or 1 mm ranges according to demand) over the entire monitoring field.

(20) Since the light curtain is positioned such that an intervention is allowed up to a certain value (distance to the dangerous spot) through the light curtain according to requirement, the reflection area of the reflection device is attached with an allowed offset to the fingertips. This offset to the fingertips (positioning at the arm, back of the hand, partial area of the fingers etc.) can be better visualized by the laser projection line of the line laser beginning at the fingertips or the supplied materials (billet etc.). The operator has the control over the position to the trigger barrier, which was not possible in previous protection devices. This results in a substantially more operator-friendly function of this safety device with avoidance of unintended stops of the machines at the same time.

(21) In order to guarantee the functional safety, it has to be ensured that the suitable reflection elements or reflection devices are used. This is realized by the two sensor devices, which are positioned with corresponding distance to each other. Thereto, the reflection devices are provided e.g. with RFID transponders. At the same time, the reflection capacities of the reflection devices can be examined by further or augmented sensor devices at the same sensor locations. This allows the control both of the use of the correct protection elements and the examination of the functionality of these protection elements.

(22) In order to release the machine, the reflection elements have to be recognized by the sensor devices at the same time. Therein, this function corresponds to a two-hand control device with two switching elements to be operated at the same time. Monitoring if the reflection devices are also correctly used, can be realized by the use of expansion and tension sensors or pulse tracker and vein detector, respectively, or the like.

(23) By the reflection devices specially worn at the body (hands) in this embodiment as the trigger elements, which are additionally monitored and controlled, high safety for dangerous machines like rolling mills can be ensured. Simple and safe work can be allowed in the danger area and inadvertent downtimes of the machines are reduced.

(24) In the following, a specific solution is presented in more detail. The safety device includes a complete safety concept, which avoids false triggers by the handling as possible and excludes operating errors by false or non-functioning reflection protection elements (reflection devices).

(25) The position of the protection area in or at the machine is determined by the manual operating requirements of the machine. This position is set in a defined distance to the dangerous spot (e.g. nip). Depending on this position, suitable reflection devices at the hands or arms are required. Since it usually has to be worked close to the protection area in manual operating functions, false shutdowns occur by the non-visible trigger area, which can considerably disturb the operating flow and result in material losses (examples: the product burns in tempered rolling mills, with still powdery additives, the product falls through with automatically opening nip).

(26) Such false triggers are avoided by the integration of a line laser, which is oriented identically to the trigger area of the light curtain. By the projection of the line on the fingers, the hand and/or on the supply material, the operator sees at all times how far he is still away from the reflection element (e.g. reflection bracelet). Thereby, an unintended emergency shutdown with the corresponding consequences can be avoided. By this device, the protection area can be very exactly set and indicated. Thereby, a substantially improved and more easily operable safety system is achieved compared to currently known systems.

(27) The function of the light curtain is optionally performed by examination of the individual sensors of the light curtain before start-up of the machine. This is manually or automatically effected by sweeping the sensors with a reflection unit.

(28) The examination of the protection elements, i.e. of the reflection devices, at the hands or arms is important to use the protection elements correct and functional for the respective machine. In particular, this is required if different machines with different requirements are operated in the environment.

(29) This examination is effected by two sensor devices positioned separated from each other, but reachable with each one hand. The reflection devices are for example provided with RFID transponders, which allow unique association. The sensor devices register the transponders and optionally examine the reflecting capacity or reflection of the reflection devices in addition or with an immediately adjacent further sensor device.

(30) The registration of each application of the reflection devices is possible and a required exchange of the reflection devices after a maximum number of applications is definable. An additional integrated infrared transmitting and receiving cell secures the functionality by examination of the reflection. The examination at the two sensor devices effected at the same time secures the correct use of the protection elements at both hands/arms.

(31) As a major field of employment, securing dangerous intervention locations of machines and plants like mixing rolling mills etc. can be regarded. However, with this approach, dangerous situations for machines and plants can also be monitored as well as protected independently of the personal protection. In particular, robot arms or other handling devices and conveyors, respectively, can also be examined and secured by these safety measures. Thereto, the dangerous situations have to be defined and indicated by this system.