Patent Publication Number: US-2021188595-A1

Title: Strain sensor for a position measuring tape of an elevator

Description:
This application claims the benefit under 35 USC § 119(a)-(d) of European Application No. 19 219 108.8 filed Dec. 20, 2019, the entirety of which is incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a sensor apparatus for an elevator with a hanging position measuring tape for detecting a critical change in length of the position measuring tape. 
     BACKGROUND OF THE INVENTION 
     Sensor apparatuses which detect that a position measuring tape has been torn off are known from the prior art, for example, from CN 108 249 245 A. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide an improved sensor apparatus. 
     The sensor apparatus according to the present invention is a sensor apparatus for an elevator with a hanging position measuring tape for detecting a critical change in length of the position measuring tape comprising a carrier with a mounting element for mounting the carrier on a stationary part of the elevator, comprising a carriage on the carrier, comprising a tape holder on the carriage with at least its securing element for securing the position measuring tape on the carriage in a fixed location and for roughly setting the length position of the position measuring tape, comprising a guide device between the carrier and the carriage with guide elements on the carrier and on the carriage for, in the parallel direction of the position measuring tape to be mounted, displaceably securing the carriage to the carrier, comprising a tensioning device between the carrier and the carriage with engagement elements on the carrier and the carriage and with a tensioning element which is secured to the engagement elements in order to move the carriage counter to the direction of the positioning tape to be secured and in order to be able to tension a secured positioning tape, comprising a detection device for detecting a critical displacement of the carriage on the carrier on the basis of a critical change in length of a position measuring tape to be mounted and for outputting a signal in the event of a detection with at least one activation element for identifying the position of a critical displacement and with a sensor for detecting the activation element in the event of a critical displacement, wherein the activation element and the sensor are alternately secured on the carrier and the carriage, and comprising an adjusting device in order to be able to set the distance between the at least one activation element and the sensor, with at least one adjusting element on the carriage and the tape holder for setting the position of the tape holder with respect to the carriage in a parallel direction of the position measuring tape to be mounted in order to be able to adjust the length position of a position measuring tape to be mounted with respect to the carriage, or on the carrier and the carriage for setting the distance between the activation element and the sensor. 
     The sensor apparatus can create the advantage that a critical change in length of a mounted position measuring tape can be detected. 
     To this end, the sensor apparatus according to the present invention can be intended to be secured to the floor or in a lower region of an elevator shaft and to receive a position measuring tape which is fastened to the ceiling or an upper region of the elevator shaft and hangs downward, to tension the position measuring tape and to detect a critical change in length of the position measuring tape. 
     The position measuring tape can have a large number of position codes. The position measuring tape can be provided for the purpose of determining the vertical position of an elevator car in the elevator shaft. To this end, the elevator car can have a further sensor apparatus which detects the position codes of the position measuring tape. 
     A change in length of the position measuring tape can be caused by a change in temperature, aging or else a fracture in the position measuring tape. A change in length is critical if it exceeds a specific threshold value. The threshold value can be selected such that a change in length can still be compensated for and processed by the position measuring system without faults without the threshold value being exceeded. 
     The detection device preferably comprises a first activation element which identifies the position of the carriage in the event of a critical extension of a position measuring tape to be mounted and a second activation element which identifies the position of the carriage in the event of a critical shortening of a position measuring tape to be mounted. 
     This can create the advantage that a critical change in length can be detected in both directions. 
     The sensor apparatus preferably has a marking element on the carrier or carriage in order to be able to set the distance between the at least one activation element and the sensor to a specific critical distance which corresponds to a critical change in length of a position measuring tape to be measured and, in particular, in the case of two activation elements, in order to be able to set the sensor to a central position between the two activation elements. 
     This can create the advantage that the adjustment of the sensor apparatus can be performed in a simple manner and, in particular, can be prespecified in a standardized manner. 
     The tensioning device preferably forms a first setting device and the adjusting device preferably forms a second setting device, in each case for changing the position of the position measuring tape to be mounted with respect to the detection device, in particular, with respect to the activation elements or to the sensor. 
     This can create the advantage that the adjustment can first be performed roughly and then I more finely. This can simplify the adjustment process. 
     The sensor apparatus preferably provides the securing of a position measuring tape composed of metal, in particular, a steel tape, which has, in particular, a sequence of optical 2D codes. 
     A critical change in length of the position measuring tape preferably corresponds to an extension or a shortening which exceeds a specific different threshold values or a common threshold value. 
     The direction of the position measuring tape to be mounted preferably corresponds to the direction toward its upper end and the parallel direction of the position measuring tape to be mounted preferably corresponds to the parallel in its direction and its opposite direction. 
     This can create the advantage that the sensor apparatus is matched to the position measuring tape in an optimum manner. 
     The mounting element of the carrier is preferably a screw hole. The carrier is preferably intended for mounting at the lower end of the elevator, in particular, on the floor of the elevator. 
     This can create the advantage that the position measuring tape is completely monitored. 
     The at least one securing element of the tape holder preferably provides two recesses in the tape holder for threading in the position measuring tape. This can create the advantage that the position measuring tape can be secured to the tape holder in a simple manner. 
     The position measuring tape is preferably intended for securing at its lower end. This can create the advantage that the entire position measuring tape is monitored. 
     The tape holder is preferably secured to the carriage in a fixed location. This can create the advantage that a critical change in length can be precisely detected. 
     The rough setting of the length position of the position measuring tape on the securing element of the tape holder the length position of the position measuring tape with respect to the carriage and the carrier is preferably made in the parallel direction of the position measuring tape. This can create the advantage that rough adjustment can be performed as early as when the position measuring tape is secured to the tape holder. 
     The guide elements of the guide device preferably have slots and support areas in the carrier and lugs and runners in the carriage, wherein the lugs engage into the slots for guiding purposes and the runners slide on the support areas for guiding purposes. 
     This can create the advantage that the carriage is guided in a displaceable manner in the parallel direction of the position measuring tape. 
     The engagement elements of the tensioning device are preferably eyes. The tensioning element of the tensioning device is preferably a spring which has hook elements which are hooked into the engagement elements of the tensioning device. 
     This can create the advantage that the position measuring tape remains tensioned and a change in length of the position measuring tape leads directly to a movement the carriage. 
     The activation elements of the detection device are preferably button elements, in particular, ramp elements, and the sensor is a tactile sensor which is activated by the ramp elements in the event of a critical displacement of the carriage. The critical displacement of the carriage is preferably effected by a critical change in length of a the position measuring tape to be mounted. 
     This can create the advantage that the detection of a critical change in length is performed in a simple manner. This can further create the advantage that the functioning of the sensor apparatus can be performed in a simple manner by visual inspection. 
     The adjusting elements of the adjusting device preferably have a row of holes in the tape holder, two threaded bores in the carriage and two associated screws, wherein different holes of the row of holes can be selectively chosen in order to secure the tape holder to the carriage by means of the screws in the threaded bores of the carriage. 
     This can create the advantage that the securing of the position measuring tape can be adjusted in a stepped manner with respect to the carriage. This can create the advantage that the detection device can be adjusted in a stepped manner. 
     The sensor apparatus preferably has a protective element for providing screening in the direction of the position measuring tape to be mounted, in particular, an extensive projection at that end of the carrier that is situated in the direction of the position measuring tape to be mounted, in order to divert away objects which may fall in from the direction of the upper end of the position measuring tape before they hit the carriage. 
     This can increase the operational reliability of the sensor device. 
     The elevator according to the present invention is an elevator comprising a sensor apparatus of the abovementioned type. The elevator can create the abovementioned advantages. 
     Further features of the present invention are indicated in the drawings. 
     The advantages mentioned in each case can also be implemented for combinations of features in the context of which they have not been mentioned. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present invention are illustrated in the drawings and will be explained in more detail hereinbelow. Like reference signs in the individual figures here denote corresponding elements. 
         FIG. 1  shows a side view of the sensor device from the front; 
         FIG. 2  shows a perspective exploded view of the sensor device; and 
         FIG. 3  shows a perspective side view of the sensor device from the right. 
     
    
    
     All the figures show the exact same sensor device in a view which is true to proportions. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows the carrier  10 , the carriage  20 , the tape holder  30 , the tensioning device  60  with the spring  63 , the detection device  70  with the upper ramp  71  and the lower ramp  72  on the carrier  10 , with the tactile sensor  73  on the carriage  20  and with the signal line  74  which is connected to the tactile sensor  73 , and also the position measuring tape  90  with a large number of 2D position codes  91 . 
     In an extension of a position measuring tape that is suspended in the upper end of the elevator shaft, the sensor device is secured by way of the screw hole  11  to the floor of the elevator shaft by means of a screw. Therefore, the orientation of the figures with respect to the top and bottom is realistic. The carrier  11  has, at the upper end, a deflection plate  12  as a protection element against falling objects. 
       FIG. 2  shows, in the individual parts, the carrier  10 , the carriage  20 , the spring  63 , the tape holder  40  with its recesses  41 , and the position measuring tape  90 . 
     During operation, the spring  63 , by way of its two hook elements  64 , is hooked into the eye  61  of the carrier  10  and the eye  62  of the carriage  20  and in this way pulls the carriage downward. 
     During operation, the position measuring tape  90  is threaded into the recesses  41  of the tape holder  40  such that the position measuring tape is non-positively fixedly secured to the tape holder when it is under tension. During threading of the position measuring tape into the recesses  41 , the position of the position measuring tape with respect to the tape holder  40  and, during operation, also with respect to the carriage can be roughly adjusted. 
     The adjusting device  80  has, on the tape holder  40 , a row of holes  81  through which two screws  83  can be inserted during operation, the screws being screwed into the screw holes  82  of the carriage  20 . Therefore, the position measuring tape is fixedly secured to the carriage during operation. The position of the position measuring tape  90  with respect to the carriage can be finely adjusted by choosing the holes of the row of holes that are used for the screws. 
     The guide device  50  has four lugs  52  on the carriage, which lugs engage into the two slots  51  of the carrier  10 , and also two runners  54  on the carriage, which runners slide on the two support areas  53  of the carrier. By way of these elements, the carriage is positively guided in a one-dimensionally displaceable manner in the parallel direction of the position measuring tape to be mounted. Therefore, the carriage can move along with the end of the position measuring tape in the event of a change in length of the position measuring tape by displacement of its position in the carrier. 
       FIG. 3  shows the detection device  70  has a tactile sensor  73  which is fixedly secured to the carriage  20  and also the upper ramp  71  and the lower ramp  72  on the carrier  10 . The tactile sensor is connected to the elevator control system via the signal line  74 . 
       FIG. 3  shows an upper ramp  71  and the lower ramp  72  the tactile sensor  73 , and also the marking element  84  on the carrier. The marking element  84  is fitted such that, when the sensor device is adjusted in such a way that the tactile sensor is situated exactly opposite the marking element, the two distances of the tactile sensor from the upper and from the lower button element are of the same length. These distances represent the length of the permitted critical change in length of the position measuring tape. 
     The adjustment is performed in such a way that the position of the carriage with respect to the hanging-down end of the position measuring tape is selected with the aid of the adjusting device such that the sensor is positioned level with the marking. Therefore, the sensor apparatus is designed such that the same critical distances are detected both for an extension and also for a shortening of the position measuring tape. This is the initial operating state of the sensor apparatus as depicted in  FIG. 1  and  FIG. 3 . 
     If the position measuring tape  90  is now shortened by more than a critical change in length, the position measuring tape pulls the carriage  20  together with the tactile sensor  73  upward against the force of the spring  63  as far as the upper ramp  71 , so that the upper ramp  71  pushes in the sensing finger of the tactile sensor  73 . In the process, the tactile sensor  73  sends a signal via the signal line  74  to the elevator control system which is to be connected to the signal line and said elevator control system can initiate, for example, emergency stopping of the elevator. 
     If the position measuring tape now extends by more than a critical change in length after the initial operating state of the sensor apparatus, the spring  63  pulls the carriage  20  together with the tactile sensor  73  downward as far as the lower ramp  72 , so that the lower ramp  72  pushes in the tactile sensor  73 . In the process, the tactile sensor  73  sends a signal via the signal line  74  to the elevator control system which is to be connected to the signal line and the elevator control system can initiate, for example, emergency stopping of the elevator. 
     LIST OF REFERENCE SIGNS 
     
         
           10  Carrier 
           11  Screw hole 
           12  Deflection plate 
           20  Carriage 
           40  Tape holder 
           41  Recesses 
           50  Guide device 
           51  Slots 
           52  Lugs 
           53  Support area 
           54  Runners 
           60  Tensioning device 
           61  Eye 
           62  Eye 
           63  Spring 
           64  Hook element 
           70  Detection device 
           71  Upper ramp 
           72  Lower ramp 
           73  Tactile sensor 
           74  Signal line 
           80  Adjusting device 
           81  Row of holes 
           82  Screw holes 
           83  Screws 
           84  Marking element 
           90  Position measuring tape 
           91  2D position codes