Patent Publication Number: US-8534722-B2

Title: Safety interlocking device with escape unlocking means

Description:
BACKGROUND 
     The invention relates to a safety interlocking device (referred to hereinafter as the SI device) with an escape unlocking means (referred to hereinafter as the EU means). Entrances to hazardous spaces have to be protected using SI devices. These devices ensure that the entrance is cleared only when specific conditions are met, so that the hazardous space may be entered safely. An SI device requires an EU means, as it must be possible to leave the hazardous space at all times, i.e. including when the entrance is closed. The escape unlocking of the SI device may therefore be possible merely from the hazardous space. The safety of the SI device is ensured by mechanisms for monitoring the interlocking state of a lock. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to propose a safety interlocking device with an economical escape unlocking means. 
     According to the invention, this object is achieved by the safety interlocking device set forth in the claims. 
     A safety interlocking device of this type comprises:
     a) A locking unit for mounting on the safe side to a door relative to a hazardous region. This locking unit comprises a guide which can be fastened to the door and a lock which is guided in the guide and has an actuating handle.   b) A locking cage for mounting on a door frame interacting with the door.   c) An escape unlocking (EU) means for unlocking the safety interlocking device. This escape unlocking means allows the safety interlocking device to be unlocked from the hazardous region. This serves to open the locked door from the hazardous region, in order to be able to escape from the hazardous region.   

     According to the invention, an economical and safe solution for an escape unlocking means is attained by the following features. 
     A device according to the invention is distinguished by the following features:
         The locking cage comprises a base plate which can be fastened to the door frame and has a bearing surface for bearing against the door frame, and a locking stop which is articulated to the base plate so as to be able to pivot about an axis from an interlocking position into an emergency opening position, and also the escape unlocking means.   The escape unlocking means has an emergency handle and at least one arresting tip. It can assume a normal position, in which it arrests the pivotability of the locking stop in the interlocking position, and an escape position, in which it releases the locking stop for pivoting into the emergency opening position.   A stretched rod piece is provided between the emergency handle and the arresting tip. This stretched rod piece and the arresting tip are embodied so as to be displaceable perpendicularly to the bearing surface on the base plate of the locking cage. In the normal position of the EU means, the arresting tip is in arresting operative connection with a first arresting surface of the locking stop and a second arresting surface of the base plate. The arresting tip as a result non-rotatably connects the locking stop to the base plate.   At least one of these operative connections can be released by displacement of the arresting tip in the rod direction.       

     Taken together, these features ensure simple operation and a simple construction of the EU means. The displacement of the arresting tip arresting the locking stop can be attained directly by displacement of the rod. At the same time, it is not possible to unlock the locking stop from the safe side, without deliberately making major changes to and interventions in the SI device. The interlocking of the locking stop can resist high forces, but can be released from the hazardous space by merely low forces. 
     In the normal position, these arresting surfaces and the axis of the locking stop are expediently positioned relative to one another in such a way that rotation of the locking stop into the emergency opening position requires pivoting of the first arresting surface into a region which the arresting tip assumes in the normal position. This arrangement of the interacting parts causes direct blocking of this movement, provided that the arresting tip is in the normal position. Movement of the locking stop means that the arresting tip is either out of operative connection with the locking stop or can be pivoted together with the locking stop. If, however, the arresting tip is in operative connection with the first and the second arresting surface, neither of the two conditions is met and the locking stop is non-rotatably connected to the base plate. 
     In a preferred embodiment, the arresting tip engages, at least in the normal position, with a hole in the locking stop. A hole in the locking stop and a round rod which interacts therewith and is inserted therein, as the arresting tip, reliably interlock rotation of the locking stop about its axis positioned perpendicularly to the axial direction of the hole. As the rod and the arresting tip are concealed within the SI device and the door frame and the emergency handle is visible and operable merely from the hazardous side, the arresting of the locking stop cannot be handled from the safe side. 
     However, the arresting tip does not need to engage with the locking stop. It can also fill out an intermediate space between an outer surface of the locking stop and an inner surface of the base plate. In this case, the intermediate space would have to be reduced, at least in a partial region, on rotation of the locking stop about its pivot axis; this is prevented by an arresting tip provided there. If, however, the arresting tip is removed from this region, the locking stop can pivot freely. 
     There can be articulated to the base plate two locking stops which can pivot in opposite directions of rotation from the interlocking position into the emergency opening position. In this case, the EU means has for each locking stop an arresting tip and a rod, which rods expediently possess a common emergency handle. The emergency handle therefore allows both rods to be displaced at the same time and therefore both locking stops to be unlocked at the same time. 
     In principle, it is possible to unlock the locking stop by pressing the emergency handle or by pulling the emergency handle. These two possibilities require different solutions in the arresting tip and rod. If the arresting tip forms the tip of the rod, then it is preferable for said tip to be able to be brought out of operative connection with the first arresting surface of the locking stop by pulling the emergency handle. Pulling the emergency handle causes the rod and the arresting tip to be jointly displaced from the safe side toward the hazardous side and thus the arresting tip to be moved out of the pivot region of the first arresting surface. In this embodiment of the arresting tip on the rod, unlocking can also be attained by pressing the emergency handle. This requires the arresting tip to fill out the above-mentioned intermediate space between the outer surface of the locking stop and the inner surface of the base plate and to have on the hazardous space side of its arresting region a less voluminous region allowing pivoting of the locking stop. 
     Unlocking by pressing the emergency handle is attained also by the following embodiment: The arresting tip is a part which is independent of the rod. It can be brought out of operative connection with the second arresting surface on the base plate by pressing the emergency handle and jointly displacing the rod and arresting tip. That is to say, the arresting tip then passes out of a guide region in the base plate, thus allowing it to pivot together with the locking stop. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described hereinafter in greater detail with reference to the figures, in which: 
         FIGS. 1A and 1B  are a view of an SI device mounted on the door and door frame in an open position and in the closed position. 
         FIGS. 2A and 2B  are a perspective view of the same mounted SI device in the positions shown in  FIGS. 1A and 1B . 
         FIG. 3  is a section through the door frame looking onto the SI device. 
         FIG. 4  is a view of the SI device without the door and door frame. 
         FIGS. 5A-5D  show four sections through the EU means. Each of the four drawings represents a different position of the unlocking means or the locking stop. 
         FIGS. 6 and 7  are sections through the EU means. In each drawing, the position of the arresting surface on the locking stop is selected differently. 
         FIGS. 8A and 8   b  and  FIGS. 9A and 9B  show four sections through an EU means filling an intermediate space between the locking stop and base plate. Each of the four drawings represents a different position of the unlocking means or the locking stop. 
         FIG. 10  is a section through an embodiment embodied with two locking stops. 
         FIG. 11  is a section through an embodiment in which the unlocking is carried out by pressing the emergency handle. 
         FIG. 12  is a section through a sixth embodiment in which the unlocking is carried out by pressing the emergency handle. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     The first embodiment illustrated in  FIGS. 1 to 6  and the second embodiment illustrated in  FIG. 7 , like the third illustrated in  FIGS. 8 and 9 , the fourth illustrated in  FIG. 10  and the fifth embodiment illustrated in  FIG. 11  of SI devices  11  possess a locking unit  13  and a locking cage  15 . 
     The locking unit  13  is fastened to a door  17  to a hazardous space: to the safe side  19  of this door. There are embodied on the hazardous space side  21  of this door  17  an emergency handle  23 , on the safe side  19  an actuating handle  25  for the lock  27 . The lock  27  is displaceably guided in a locking guide  29 . The locking guide  29  is screwed to the door  17 . 
     The locking cage  15  is arranged on the door frame  18 . It possesses a base plate  31  and a locking stop  33  articulated thereto. The locking stop  33  can pivot about the pivot axis  35 , provided that this pivoting is released by actuating the escape unlocking means. The lock  27  reaches, in the closed position of the SI device, between the base plate  31  and locking stop  33 . The locking stop  33  is arrested by the escape unlocking means in its normal position, i.e. so as to be unable to pivot relative to the base plate  31 . The door  17  is therefore interlocked. 
     The interlocking is generally monitored by electronic means and/or electromechanical means and/or magnetic means. This involves monitoring the position of the lock relative to the locking stop. In addition, the arresting of the locking stop is generally monitored. The monitoring means do not form the subject-matter of the present invention, although SI devices according to the invention are generally speaking equipped with such means. 
     Essential to the invention is the simple manner in which the locking stop is arrested. This can take place in a slightly different manner without departing from the inventive concept: 
     In the first exemplary embodiment illustrated in  FIGS. 1 to 6 , the second exemplary embodiment illustrated in  FIG. 7  and the fourth and fifth exemplary embodiments illustrated in  FIGS. 10 and 11 , in the normal position an arresting tip  41  is positioned at all times in a hole  43  in the locking stop  33 . The hole  43  is formed perpendicularly to the bearing surface  45  of the base plate. Axially to the first hole  43  in the locking stop  33 , a second hole  47  is also formed in the base plate  31 . The arresting tip  41  extends through both holes  43 ,  47 . Because the first arresting surfaces in the first hole and the second arresting surfaces in the second hole are not arranged coaxially with the pivot axis  35 , they have to pass through a relative change in angle in relation to one another during pivoting of the locking stop. However, this change in angle is prevented by the rigid arresting tip  41 . Said arresting tip is in abutment with the two abutment surfaces and therefore does not permit pivoting. However, displacement of the arresting tip along its axis extending perpendicularly to the bearing surface of the base plate allows it to be brought out of operative connection with one of these arresting surfaces. 
     In this respect, exemplary embodiments 1, 2 and 4 differ from exemplary embodiment five according to  FIG. 11 . In the first exemplary embodiments, the arresting tip is part of a rod  49  on which the emergency handle  23  is embodied. By pulling the emergency handle, the rod  49  and the arresting tip  41  are jointly pulled out of the engagement with the first hole in the locking stop. However, in the exemplary embodiment according to  FIG. 11 , the rod  49  and the arresting tip  41  form two mutually independent parts. However, in the normal position, they are arranged coaxially and embodied so as to be jointly displaceable. If the emergency handle  23  is pulled, then the distance between the arresting tip  41  and the tip of the rod increases. The arresting tip  41  remains in this case without alteration in operative connection both with the arresting surface in the base plate  31  (second hole) and with the arresting surface in the locking stop (first hole). Such movement of the emergency handle  23  and the rod  49  can therefore be prevented. If on the other hand, the emergency handle  23  is pressed, then the tip of the rod brings the arresting tip  41  out of engagement with the base plate. The pressure acting on the arresting tip  41  is transmitted to the locking stop  33  via the spring  51 , so that said locking stop springs open. By pressing on the door and the lock, the locking stop can then be pivoted through 90 degrees and the door then pushed open. 
     Still another escape unlocking is realised in the exemplary embodiments according to  FIGS. 8-9  and  12 . In these third and sixth exemplary embodiments, the interlocking tip  41  does not engage with the locking stop  33 . Formed between the locking stop  33  and a fastening flange  53  on the base plate  31  is an intermediate space  55  which is filled out by a plate-shaped arresting tip  41 . During pivoting of the locking stop, parts of the locking stop  33  are pivoted into the region of this intermediate space  55 . This is prevented by the arresting tip  41  which is arranged there. Forces which seek to pivot the locking stop  33  are conducted via the outer surface of the locking stop  33  onto the arresting tip  41  and therefrom onto the fastening flange  53 . Thus, in this embodiment too, the arresting tip  41  ensures that the locking stop  33  is non-rotatably arrested relative to the base plate  31 . 
     By pulling the emergency handle  23  of the exemplary embodiment according to  FIGS. 8 and 9 , the rod  49 , and thus the arresting tip  41 , is displaced in the direction toward the hazardous space. As a result, the leading end of the arresting tip  41  passes after an escape perpendicularly to the direction of displacement of the arresting tip and through the pivot axis  35  of the locking stop  33 . From this moment, the intermediate space, which is necessary for the pivoting of the locking stop  33 , between the locking stop and the base plate is free and the locking stop can pivot. 
     However, in the exemplary embodiment according to  FIG. 12 , the EU means  39  is designed for pressure acting on the emergency handle  23  for unlocking the locking stop  33 . The arresting tip  41  is thickened right at the front, so that after this thickening  57  there is an intermediate space  59  between the arresting tip  41  and the outer surface of the locking stop  33 . By pressing the emergency handle  23 , this thickening is pushed toward the safe side beyond the stop region on the locking stop  33 . The locking stop can now be pivoted, as the intermediate space  59  cannot put up any resistance to the parts of the locking stop that pivot toward the arresting tip. In this design, it is also possible to pull the emergency handle  23  in order to unlock the locking stop. A design of this type therefore provides an SI device, the EU means of which is unlocked both by pulling and by pressing the emergency handle. One of both possibilities can also be purposefully prevented by configuring a corresponding stop to prevent a pulling movement or a stop to prevent a pushing movement. A stop of this type can be provided to prevent handling from the safe side. 
     In summary, the invention may be regarded as a safety interlocking device ( 11 ) comprising a locking unit ( 13 ) for mounting on the safe side ( 19 ) to a door ( 17 ) relative to a hazardous region, and a locking cage ( 15 ) for mounting on a door frame ( 18 ) interacting with the door ( 17 ). In order to be able to open, from the hazardous region, the locked door ( 17 ) and escape from the hazardous region, an escape unlocking means ( 39 ) is provided for unlocking the safety interlocking device ( 11 ). The locking cage ( 15 ) has a locking stop which is articulated to a base plate ( 31 ) so as to be able to pivot about a pivot axis ( 35 ) from an interlocking position into an emergency opening position. The escape unlocking means ( 39 ) possesses at least one arresting tip ( 41 ) which, in an escape position, releases the locking stop ( 33 ) for pivoting into the emergency opening position. Provided between an emergency handle ( 23 ) and the arresting tip ( 41 ) is a stretched rod piece ( 49 ) which is embodied so as to be displaceable together with the arresting tip ( 41 ). In the normal position of the EU means ( 39 ), the arresting tip ( 41 ) is in arresting operative connection with a first arresting surface of the locking stop ( 33 ) and a second arresting surface of the base plate ( 31 ). At least one of these operative connections can be released by displacement of the arresting tip ( 41 ) in the rod direction.