Abstract:
An assembly for locking a movable protective door disposed in front of a point to be shielded, the device comprising
       two rails extending parallel to one another, in which the door is guided and adjusted by a servo device,   a locking element interacting with a guide column extending parallel to the rails for locking the door, or a locking circuit by which the servo device can be deactivated,   and a contact strip attached to the door and in driving connection with the locking element, or electrically connected to the locking circuit,       
 
     advance speed of the door being adapted to be increased without violating statutory safety provisions for stopping the component, 
     wherein a recovery device is disposed between the contact strip and the door, and is in driving connection with the contact strip, such that when the contact strip makes contact with an obstacle protruding into the access point, the recovery device is activated by resistance of the obstacle, and the contact strip is moved in the direction of the component by the recovery device.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a device for locking a movable component, in particular a protective, or sliding, door arranged in front of a working, or access, point to be shielded. 
         [0003]    2. Description of the Prior Art 
         [0004]    A locking device of this kind is disclosed in EP 2 562 464 A1, and is used for locking a component held in a movable arrangement between profile rails. For safety reasons, it is desirable for a working point on a machine tool, or an access area, for example, of an elevator, or a sliding door on a train, to be secured when an obstacle is introduced into the working, or access, area inadvertently, so as to avoid injuries or damage to the component in question, or the obstacle. 
         [0005]    In order to achieve the locking of the component, especially a sliding or protective door, a guide column is provided extending parallel to the profile rails and interacting with a locking element in the locked condition of the component. The locking element encloses the guide column, in whole or in part, and is in a driving active connection with a contact strip mounted on the component in an articulated arrangement. If the contact strip encounters an obstacle when the component is advanced, mechanical connection elements activate the locking element by swivelling of the contact strip. The swivelling of the contact strip moves the mechanical connection elements out of their initial position to an end position, and this movement is passed onto the locking element, with the effect that it is moved from a position enclosing the guide column to a position that interacts with the guide column in a friction-locking arrangement. Consequently, a driving, or force-locking, active connection is created between the locking element and the guide column by means of which the component is reliably stopped, so as to avoid damage to the introduced obstacle or, in the event that a part of the human body is involved, injury is avoided. 
         [0006]    Locking devices of this kind have proven effective in practice, although it has been revealed that such components can only be moved with a particular advance speed. 
         [0007]    To exclude the possibility of damaging the obstacle introduced into the working or access point, it is necessary to stop the component with speed. As a result of the mechanical connection elements, there is a time lag between the first contact made by the contact strip with the obstacle and the actuation of the locking element. Furthermore, the locking element requires a certain length of travel to be covered along the guide column in order to exert sufficient force on the guide column so that the component will be stopped. However, the faster the component is advanced, the greater the distance covered by the component following first contact between the contact strip and the obstacle, as a result of which the danger of damage or injury is to considerably increased. 
       SUMMARY OF THE INVENTION 
       [0008]    The object of the present invention is, therefore, to provide a device of the aforementioned type for locking a component at a significantly faster advance speed so that the movement of the component can be used without violating statutory safety provisions defined in standards for stopping or locking of the component. 
         [0009]    Because there is a recovery device disposed between the contact strip and the component, and the recovery device is in a driving connection with the contact strip, when the contact strip makes contact with an obstacle protruding into the working or access point, the recovery device is deactivated by the resistance of the obstacle such that the contact strip is moved, or swivelled, in the direction of the component by the recovery device. A situation is achieved in which, firstly, the contact strip activates the locking device and the component is secured after a specific time and, secondly, sufficient space is made available before the contact strip, or the bottom edge of the component, strikes the obstacle. As a result, the distance between the bottom edge of the component and an introduced obstacle is increased and there is more time available for the movement of the component to be stopped. 
         [0010]    Furthermore, the length of time during which the contact strip remains attached to the component in a manner which allows it to move, or swivel, is increased, meaning that the activation of the recovery device actively pulls the contact strip back from the danger zone represented by an obstacle. Also, when the contact strip is attached to the component in a way that allows it to move in a linear direction, the contact strip can be pulled back from the danger area in the direction of the component by means of the recovery device, because the recovery device is able to achieve a faster recovery movement for the contact strip than the prevailing advance speed of the component. 
         [0011]    It is advantageous for the recovery device to incorporate a pull rod attached to the contact strip and to the component, with the effect that when the component is in the usual actuation status there are no relative movements between the recovery device and the component, because the recovery device is permanently moved together with the component. Furthermore, the recovery device features a pre-stressed coil compression spring (or another energy storage element) which is arranged between a sliding block and the contact strip. The sliding block in this case is mounted in a detent seat. As soon as the contact strip encounters an obstacle, a force is transmitted via the contact strip and the pull rod to the sliding block, as a result of which it is moved out of the detent seat. The preload force of the coil compression spring now causes the contact strip to be actively drawn in, or opposite to, the advance direction of the bottom edge of the component, and in a preferred embodiment this takes place at a speed that is faster than the advance speed of the component, as a result of which the contact strip is immediately moved to an underside, or bottom edge, of the component. This releases the space available between the bottom edge and the contact strip when the contact strip is actuated, in order to lock the component. At the same time, the dynamic mass of the contact strip is reduced. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The drawings show a sample embodiment configured in accordance with the present invention, the details of which are explained below. In the drawings, 
           [0013]      FIG. 1A  is a perspective now showing a device for locking a component moveable between two profile rails, on the underside of which a contact strip is provided, with a servo device by means of which the component is moved, and with a guide column by means of which the component is locked via a locking element in the event of actuation, 
           [0014]      FIG. 1B  is an elevational front view showing the device in accordance with  FIG. 1A , in a non-actuated initial position, 
           [0015]      FIG. 1C  in an elevational front view showing the device in accordance with  FIG. 1A , in an actuated status, 
           [0016]      FIG. 2A  in an elevational view showing a section of the device in accordance with  FIG. 1B , with a recovery device, in a non-actuated status, 
           [0017]      FIG. 2B  illustrates the recovery device in accordance with  FIG. 2A , on first contact between the contact strip and an obstacle, 
           [0018]      FIG. 2C  illustrates the recovery device in accordance with  FIG. 2B , in actuated status of the contact strip, 
           [0019]      FIG. 2D  is a magnified view of the recovery device in accordance with  FIG. 2A , with a detent seat, and a sliding block secured therein, 
           [0020]      FIG. 3A  is a magnified sectional view of the recovery device in accordance with  FIG. 2A , in an alternative embodiment, 
           [0021]      FIG. 3B  illustrates the device in accordance with  FIG. 1A , in which the recovery device is connected to the servo device, 
           [0022]      FIG. 4A  is a perspective view of the device in accordance with  FIG. 1A , 
           [0023]      FIG. 4B  are elevational views of the device shown with  FIG. 4A , and  4 C 
           [0024]      FIG. 5A  are perspective views showing the device in accordance to  5 D with  FIG. 1A  with differently embodied contour profiles for the contact strip and a bottom edge of the component. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]      FIGS. 1 to 4C  disclose a device  1  for locking a movable component  2 , especially a sliding or protective door arranged in front of a working or access point of a machine, or an access, to be shielded. The component  2  moves in a vertical adjustment direction  5  in order to close off the working point on the machine-tool, on a conveyor belt, or another machine, from the outside during the machining process, as a result of which it is not accessible and is, to this extent, protected. It goes without saying that the component  2  can also be moved in the horizontal or a sloping plane if, for example, the entrance area at an access is to be closed, or for entry to the access. 
         [0026]    For loading and unloading of the working point, it is necessary for the component  2  to be lifted opposite to the adjustment direction  5 . For this purpose, the component  2  is held in two C or U-shaped profile rails  3  and  4  that are aligned in parallel to, and at a distance from, one another. 
         [0027]    Furthermore, a servo device  11  is provided, for example, in the form of an electric motor, by means of which a V-belt  12  is driven. The device  1  is attached to the V-belt  12  in a specified position, and is thus in a driving connection with the V-belt  12  and the component  2 . Consequently, rotation of the V-belt  12  causes the component  2  to move up and down in the profile rails  3  and  4 . A reversing wheel  10  is provided in the area of a base  28  of the working point in this case, by means of which the V-belt  12  is guided and secured. 
         [0028]    If, during the closing movement of the component  2 , i.e., movement in the adjustment direction  5 , a member of the operating personnel incorrectly operates the working point of the machine tool and, for example, reaches into it thereby generating an obstacle, his or her arm could be trapped by the movement of the component  2  between the component  2  and a closing edge  27 , thereby injuring it. For safety reasons, the component  2  must therefore be stopped immediately if it encounters an obstacle during its adjustment movement downwards. For this purpose, a contact strip  18  is attached to the bottom edge of the component  2  and is mounted on the component  2  in such a way as to allow it to swivel outwards or move in the plane of the component  2 , and the contact strip  18  has an angle rail  19  attached to it as a mechanical connection element, which is connected to a rocker  20 . In this case, the rocker  20  is mounted in a swivelling arrangement on the device  1  and as soon as the contact strip  18  is pressed outwards or lifted in a linear direction, as shown in  FIGS. 4A and 4B , the rocker  20  is pushed downwards and a locking element  21  of the device  1  is activated for locking the component  2 . The locking element  21  in this case consists of a holding plate of a rectangular design that is worked into an opening  23 . 
         [0029]    A guide column  7  is provided in parallel to, and at a distance from, one or both sides of the profile rails  3  and  4 , and the locking element  21  extends along the guide column  7  with play. Consequently, the opening  23  is almost completely filled by the guide column  7 ; however, the inside of the opening  23  does not make contact with the outside of the guide column  7  during the lifting movement of the component  2 , as a result of which there is no contact in the normal operating status, and thus there is also no wear whatsoever on the guide column  7  or the inside of the opening  23 . 
         [0030]    If, however, the contact strip  18  is actuated and pushed outwards, or raised in a linear direction, this causes the locking element  21  to move such that the opening  23  is tilted out of the horizontal plane and thus, as is shown in  FIGS. 4B and 4C , a force-locking active connection results between the guide column  7  and the locking element  21 , which gives rise to a braking force by means of which the adjustment movement of the component  2  is stopped, and a braking force is applied to the guide column  7 . 
         [0031]    In order to release the locking element  21  from the guide column  7 , it is initially necessary for the locking element  21  to be moved to its initial position, and then for the contact strip  18  to be pushed to its vertical initial position again, as a result of which the compression springs provided on the locking element  21 , but not illustrated, and a spring element  33  provided on the contact strip  18  are preloaded. The compression springs establish the reliable active connection between the locking element  21  and the guide column  7 . 
         [0032]    In particular,  FIGS. 1A ,  1 B and  1 C show that a recovery device  31  is provided between the component  2  and the contact strip  18 . The recovery device  31  in this case consists of a pull rod  32  running parallel to the movement direction of the component  2 . The pull rod  32  is firmly connected to the contact strip  18 . The function of the recovery device  31  is to move the contact strip  18  actively and more rapidly than the advance speed of the component  2  in the direction of the component  2 . In this case, the contact strip  18  is located at a distance from the bottom edge of the component  2  in order to lock the component  2  as soon as the contact strip  18  encounters an obstacle. 
         [0033]      FIGS. 1B and 10  show a fixed position  13  of the pull rod  32 , and thus of the contact strip  18 , as well as an end position  14  of the pull rod  32  and contact strip  18 . 
         [0034]      FIGS. 2A ,  2 B and  2 C show the different movement sequences of the pull rod  32 , which is moved from the fixed position  13 , through a transitional position shown in  FIG. 2B , to the end position  14 , and as it does so draws the contact strip  18  in the direction of the component  2  in the plane formed by the component  2 , i.e. in a linear direction. 
         [0035]      FIG. 2D  shows that a sliding block  37  is attached to the free end of the pull rod  32  facing away from the component  2 . A coil compression spring, or the spring element,  33  is preloaded between the sliding block  37  and the bottom edge of the component. 
         [0036]    The sliding block  37  consists of a ring surface  39  running at right angles to the axis of symmetry of the pull rod  32 , in which case the ring surface  39  is located at an angle of 15° outward from the plane running perpendicular to the pull rod  32 . Furthermore, a detent seat  38  is provided in the component  2 , and is formed from two half-shells  40 ′ and  40 ″. The two half-shells  40 ′ and  40 ″ enclose the sliding block  37  in the manner of tongs and the internal diameter formed, or enclosed, by the half-shells  40 ′ and  40 ″ is smaller in dimension than the outer circumference of the ring surface  39  of the sliding block  37 , as a result of which the pull rod  32  is secured by the half-shells  40 ′ and  40 ″ or the detent seat  38 , in spite of the fact that the spring element  33  is preloaded, and thus the pull rod  32  does not move. 
         [0037]    The two half-shells  40 ′ and  40 ″ are mounted on the component  2  by means of an articulated joint  16 . Consequently, as soon as the contact strip  18  first encounters an obstacle, as shown in  FIG. 2   a , a force is applied to the articulated joint  16  and thus also to the half-shells  40 ′ and  40 ″, as a result of which they are swivelled outwards and open, because the ring surface  39  presses against the contact surfaces formed by the detent seat  38 . As a result of the angled arrangement of the ring surface  39 , the half-shells  40 ′ and  40 ″ are forced outwards and open, and the preload force of the spring element  33  causes the pull rod  32  to be moved opposite to the direction of movement of the component  2 . As soon as the pull rod  32  has reached the end position  14 , the movement energy of the pull rod  32  is dampened by a coil compression spring  17 , as a result of which the contact strip  18  does not strike against the bottom edge of the component  2 . 
         [0038]    As shown in  FIG. 3A , the pull rod  32  can also be activated by means of a piston  34  opposite to the movement direction of the component  2  when the contact strip  18  makes contact with an obstacle. In this case, the piston  34  is arranged in a piston space  35  containing a medium  36  under a specific pressure. As soon as the swivelling-open of the two half-shells  40 ′ and  40 ″ allows the medium  36  to escape from the piston space  35 , the pull rod  32  is moved as a result of which the contact strip is also actuated. 
         [0039]      FIG. 3B  shows the electrical connection between the recovery device  31  and the servo device  11  as a schematic view. The components for locking the component  2 , especially the locking element  21  and the guide column  7 , are not required in this embodiment. 
         [0040]    Rather, the component  2  is locked because when the contact strip  18  is activated, the recovery device  31  initially pulls back the contact strip  18  opposite to the movement direction of the component  2 , as described in the previous figures, at a faster speed than the advance speed of the component  2 , and at the same time this generates an electrical switching signal which is carried along electrical cables  25  to a switch  26 . These electrical switching signals cause the switch  26  to open, as a result of which the servo device  11  is immediately electrically decoupled from a current source, and is thus blocked. The electrical cables  25  and the electrical switch  26  thus form a locking circuit that is not illustrated, by means of which the servo device  11  is separated on activation of the contact strip  18 . 
         [0041]      FIG. 5A  shows the linear embodiment of the contact strip  18  and the bottom edge of the component  2 , which are connected together via two holding arms  51  that are spaced apart and extend parallel to one another. The holding arms  51  are connected both to the component  2  and to the contact strip  18  by an articulated joint  52 . Optionally, two guide arms  53  spaced apart from and running parallel to one another, each of which is connected to the corresponding holding arm  51  by means of an intersection point  54  in a scissor-type or crossways connection, can also be attached to the component  2  and to the contact strip  18  by an articulated joint  52 . 
         [0042]    The use of two holding arms  51  running parallel to, and at a distance from, one another means that there is a rotational movement of the contact strip  18  about the two connection points on the component  2 , and specifically in the direction in which the holding arms  51  are aligned. 
         [0043]    The additional attachment of the guide arms  53  gives rise to a linear movement of the contact strip  18  in the plane formed by the component  2 . 
         [0044]      FIG. 5B  shows that the contour of the contact strip  18 , and the bottom edge of the component  2 , can be undulating in shape, because the corresponding holding arms  51  can be attached between the contact strip  18  and the component  2  such that they absorb the reliable movement of the contact strip  18  for locking the component  2 . 
         [0045]      FIG. 5C  shows that the contact strips  18  can extend at right angles to one another, for example, in order to reproduce a U-shaped contour track of the component  2 . In the corresponding corner areas, both contact strips  18  running adjacent to one another are locked onto one another mechanically by means of a rigid screw connection, and no rotating articulated connections are required. Irrespective of the position on the particular contact strip  18  at which an obstacle prevents the movement of component  2 , this obstacle triggers activation of the recovery device  31 , with the result that triggering of the contact strip  18 , and thus locking of the component  2 , are triggered along the entire contour track of the contact strip  18 . 
         [0046]      FIG. 5D  shows that a toggle lever  61  is arranged between the contact strip  18  and the component  2 . The toggle lever  61  consists of two arms that are connected together by an articulation pin  62  that is to be regarded as the intersection point for the two arms  63  and  64  forming the toggle lever  61 . 
         [0047]    The arm  63  projecting at right angles from the articulation pin  62  is connected in this case to the component  2 , and the other arm  64  is connected to the contact strip  18 . In addition, a pin  65  is attached to the arm  64 , and the pin  65  presses against a holder  67  via an inclined plane  66 , with the holder  67  in turn being attached to the contact strip  18 . Pressure is built up by the compression spring  33  that is, in turn, attached to the pull rod  32 . 
         [0048]    As soon as the contact strip  18  encounters an obstacle during movement of the component  2 , the trouble lever  61  is activated because it pushes the preloaded compression spring  33  upwards. The inclined plane  66  provided in the holder  67  means the compression spring  33  can be placed under a very powerful preload, resulting in a fast recovery speed. Furthermore, the inclined plane  66 , combined with the pin  65 , offers the advantage that, in spite of a high spring preload force, the is release force of the contact strip remains very low, as does the dynamic impact mass at high speeds. 
         [0049]    It is also possible to equip the recovery device  31  with electric means of driving and triggering in order to move the contact strip  18  in the direction of the component  2  when encountering an obstacle. For this purpose, mechanical, or optical, sensors are attached to the underside of the contact strip  18  facing towards the movement direction, which can, for example, comprise a pressure plate, or pressure button, or a waveguide functioning as a kind of light barrier. As soon as an obstacle triggers the sensors, or interrupts their light beam, electrical switching signals actuate the electric means of driving with the effect that the pull rod  32  is moved upwards or opposite the movement direction of the component  2  by the electric means of driving, resulting in the component  2  being moved away from the obstacle.