Patent Publication Number: US-2005121453-A1

Title: Unscrewing security device for containers

Description:
The present invention relates to a device for preventing unscrewing of a closure cap, which can be mounted on a stationary stub of a container, in particular a motor vehicle radiator, as generically defined by the preamble to claim  1 .  
      In one such unscrewing prevention device, known from European Patent Disclosure EP 0 760 789 B1, a control bolt of the twist preventer is acted upon, counter to the action of a compression spring, by a so-called memory spring, which expands at a suitably high temperature. The control bolt is disposed in an axial blind bore of a thickened portion of the stub that is provided with the counterpart closure element. In this disposition of the twist preventer, it is difficult to bring the heat, which exists concretely in the container, to the heat-variable memory spring without major temperature losses.  
      The object of the present invention is therefore to create an unscrewing prevention device of the type defined at the outset whose twist preventer is disposed in an optimal way for the delivery of operating data.  
      For attaining this object, in an unscrewing prevention device of this type, the characteristics recited in claim  1  are provided.  
      By the provisions according to the invention, depending on the type of drive mechanism intended for the twist preventer, an optimal position of the drive mechanism with a view to delivering the operating data to be employed is attainable.  
      In one embodiment, the characteristics of claim  2  are provided, which means that the housing that receives the drive mechanism is disposed in an optimal way at the place where the pressure or temperature are directly present. Moreover, the housing is accommodated in a space-saving way. In this respect, the characteristics of claim  3  and/or claim  4  may advantageously be provided.  
      In another exemplary embodiment having the characteristics of claim  5 , the housing is mounted on the outside of the container whenever the operating data have been taken from the operating status of the engine. This moreover has the advantage that the container itself needs to change only insignificantly. In this respect it may be expedient to provide the characteristics of claim  6 .  
      Advantageous structural features in terms of the twist preventer are obtained from the characteristics of one or more of claims  7  through  10 .  
      Various ways of triggering the drive mechanism are advantageously apparent from the characteristics of claims  11 ,  12 ,  13 , and  14 .  
      Advantageous structural features in terms of the housing and the diaphragm will become apparent from the characteristics of one or more of claims  15  through  18 . 
    
    
      Further details of the invention can be learned from the ensuing description, in which the invention is described and explained in further detail in terms of the exemplary embodiments shown in the drawing.  
      Shown are:  
       FIG. 1 , in a schematic longitudinal section, a closure cap mounted on a motor vehicle radiator, with a pressure-controlled twist preventer, in a first exemplary embodiment of the present invention, the half-sections on the right and left of the twist preventer each representing one of the two terminal positions;  
       FIG. 2 , a view corresponding to  FIG. 1 , but with a temperature-controlled twist preventer in a second exemplary embodiment of the present invention;  
       FIG. 3 , a view corresponding to  FIG. 1 , but with an electromagnetically controlled twist preventer in a third exemplary embodiment of the present invention;  
       FIG. 4 , a view corresponding to  FIG. 1 , but with a negative-pressure controlled twist preventer in a fourth exemplary embodiment of the present invention; and  
       FIG. 5 , a view corresponding to  FIG. 1  of a pressure-controlled twist preventer, but in a fifth exemplary embodiment of the present invention.  
    
    
      The device  10 ,  110 ,  210 ,  310 ,  410  for preventing unscrewing of a cap or the like shown in a plurality of exemplary embodiments in the drawing is used for operationally controlled prevention of unscrewing of a closure cap  11 ,  111 ,  211 ,  311 ,  411  from the closure element  12 ,  112 ,  212 ,  312 ,  412  of a container  13 ,  113 ,  213 ,  313 ,  413 , for instance a motor vehicle radiator, whenever, because of the operating state of the container (increased pressure or temperature), unscrewing the closure cap from the container stub can be dangerous to the user.  
      The closure cap  11 ,  111 ,  211 ,  311 ,  411  has an outer part  14 ,  114 ,  214 ,  314 ,  414  with a grip element  16 ,  116 ,  216 ,  316 ,  416 , which is integrally provided with a closure element  17 ,  117 ,  217 ,  317 ,  417 , which here serves a female thread  18 ,  118 ,  218 ,  318 ,  418  for screwing the closure cap onto and unscrewing it from the opening of the stub  12 ,  112 ,  212 ,  312 ,  412 , which has a male thread  19 ,  119 ,  219 ,  319 ,  419 , of the motor vehicle radiator  13 ,  113 ,  213 ,  313 ,  413  or other container. It is understood that the closure element  17 ,  117 ,  217 ,  317 ,  417 , instead of having a thread, may be provided with a bayonet mount element, which can be connected to a corresponding bayonet mount element on the stub. An inner part  21 ,  121 ,  221 ,  321 ,  421  of the cap is disposed in suspended fashion, concentrically with the closure element  17 ,  117 ,  217 ,  317 ,  417 , on the inside of the grip element  16 ,  116 ,  216 ,  316 ,  416 . The inner part  21 ,  121 ,  221 ,  321 ,  421  of the cap is rotatable relative to the grip element  16 ,  116 ,  216 ,  316 ,  416  of the outer part  14 ,  114 ,  214 ,  314 ,  414  of the cap but is axially held firmly. The inner part  21 ,  121 ,  221 ,  321 ,  421  of the cap is embodied as a valve pot and receives an overpressure/negative-pressure valve assembly  22 ,  122 ,  222 ,  322 ,  422 , shown only schematically in dashed lines, whose overpressure valve is triggerable in one or two stages.  
      The unscrewing prevention device  10 ,  110 ,  210 ,  310 ,  410  has a twist preventer  25 ,  125 ,  225 ,  325 ,  425 , which has a drive mechanism  27 ,  127 ,  227 ,  327 ,  427 , disposed in a housing  26 ,  126 ,  226 ,  326 ,  426  provided inside or outside the container  13 ,  113 ,  213 ,  313 ,  413 , and this drive mechanism actuates a locking bolt  28 ,  128 ,  228 ,  328 ,  428  in order to cause it to engage or disengage a detent opening  29 ,  129 ,  229 ,  329 ,  429  in the grip element  16 ,  116 ,  216 ,  316 ,  416  of the closure cap  11 ,  111 ,  211 ,  311 ,  411 . In the various exemplary embodiments, the drive mechanism  27 ,  127 ,  227 ,  327 ,  427  is triggerable in accordance with various specifications.  
      In the exemplary embodiment of  FIG. 1 , the drive mechanism  27  is triggerable by the internal pressure existing in the container  13 . To that end, the housing  26  that receives the drive mechanism  27  is disposed in a region inside the container  13  and below the male thread  19  of the stub  12  and opposite an outer region of the grip element  16  of the closure cap  11 . The housing  26  has a cylindrical part  31 , which protrudes inward integrally from the inner wall of the container  13  and is closed by a cap part  32  that is provided with a plurality of evenly distributed connecting openings  39 . An insert  33  is disposed inside the cylindrical part  31  and is clamped in the cylindrical part  31  by the cap part  32  and serves as a guide element for the locking bolt  28 . The locking bolt  28 , disposed axially movably inside the housing  26 , penetrates the container wall that forms the housing bottom, and in this region the locking bolt is for instance round in the manner of a pin. Inside the housing  26 , the locking bolt  28  has a widened portion with an annular groove  34 , in which a compression spring  36  surrounding the pinlike bolt region is received, which spring is braced at one end on the bottom of the annular groove  34  and on the other on the insert  33 . This compression spring  36  presses the locking bolt  28  against a diaphragm  40 , which is acted upon by the pressure in the container interior and is fastened in pressuretight fashion on its outer circumference between the cap part  32  and the insert  33 . As can be seen from the two half-sections in  FIG. 1 , the diaphragm  40 , in its middle region  37  against which the locking bolt  28  is pressed, can be deflected counter to the action of the compression spring  36  whenever the pressure in the interior of the container  13  exceeds a certain value. Opposite the end of the locking bolt  28  protruding out of the container  13 , the grip element  16  is provided with an axial through opening  38 , which the locking bolt  28  can engage when the diaphragm  40  has been deflected and can thus prevent relative rotation between the grip element  16  and the container stub  12 . The through opening  38  in the grip element  16  is continuous here, or in other words is accessible from the outside, so that professionals will still be able to unlock and accordingly open the closure cap  11  intentionally.  
      The exemplary embodiment shown in  FIG. 2  is similar to that shown in  FIG. 1 , with the distinction that the drive mechanism  127  in the housing  126  is tg and driven as a function of the temperature that occurs in the interior of the container  113 . While the locking bolt  128 , compression spring  136 , insert  133 , and cylindrical part  131  are structurally essentially identically embodied and disposed in terms of position, the drive mechanism  127  has a thermocapsule  140 , which contains an expanding material that expands under the influence of heat if the temperature increases. The thermocapsule  140  is braced on the inside of the cap part  132 . Located on the thermocapsule  140  is a sealing diaphragm  141 , whose middle region is disposed between the top side of the thermocapsule  140  and the opposed underside of the widened region of the locking bolt  128 . The circumferential region of the sealing diaphragm  141  is clamped or fastened between the cap part  132  and the insert  133 . For direct transmission of the heat from the container interior to the thermocapsule  140 , or its expanding material, the cap part  132 , just like the cap part  32  in the pressure-controlled tv  27  or  40 , is provided with connecting openings  139  distributed preferably evenly over the circumference. The through opening  130 , opposite the housing  126  or the locking bolt  128 , in the grip element  116  is also embodied approximately in the same way.  
      In the exemplary embodiment shown in  FIG. 3 , the drive mechanism  227  is formed an electromagnet  245 , which is provided in a housing  226  that once again has a cylindrical part  231 , suspended integrally inward into the container on the inside of one region of the container wall. The cylindrical part  231  is likewise covered by a cap part  232 , and the cap part  232 , with contact and fixation ribs  246 , serves to receive the electromagnet  245  and retain it. The electromagnet  245  has a coil  248 , inside which a locking bolt  228 , as an armature, is axially movable. The locking bolt  228  penetrates an opening in the container wall and protrudes out of the container  213 , opposite a corresponding detent bore  238  in the grip element  216 . Inside the housing  226 , in the container wall, a moisture-proof duct  249  is provided, through which a connection cable  251  is carried to the electromagnet  245 . The connection cable  251  leads to a controller, not shown, which detects the operating state of the engine of the motor vehicle.  
      In the exemplary embodiment shown in  FIG. 4 , the drive mechanism  327  is formed by a negative-pressure diaphragm  345 , which is inside a housing  326  that is located outside the container  313 . The external housing  326  is disposed and retained on one region of the container wall. For that purpose, the container  313  has a circumferential flange  352 , which is concentric with the stub  312  that is provided with the male thread  319 , and which has a spacing such that on its outer circumference it is approximately aligned with the outermost circumference of the grip element  316 . The housing  326  is retained in the flange  352  or in the applicable region  355  of the wall of the container  313 , for instance by means of a tongue and groove connection  353  and  354 , and remote from the flange  352 , it is retained in clamping fashion on its back side by a detent bracket  356  and thus is retained in an optionally replaceable way. The housing  326  is embodied in two parts; the negative-pressure diaphragm  345  is clamped on the outer edge between the two housing parts  357  and  358 . The housing part  357  at the back, remote from the closure cap  311 , acts as a guide for the locking bolt  328 , which is connected to the negative-pressure diaphragm  345  in a manner fixed against relative motion. The housing part  358 ′ oriented toward the closure cap  311  is provided with a through bore for the locking bolt  328 , which bolt simultaneously protrudes into a bore  359  of the flange  352  and can reach into a detent opening  338  of the grip element  316  of the closure cap  311  (as shown in dashed lines). This detent opening  338  may be embodied as an oblong hole or in the form of a slit that is open from the face end. The negative-pressure diaphragm  345  is U-shaped, for instance, specifically in both of its terminal positions. A negative-pressure bore  344  leads into the housing  326  and is connected to the engine in a manner not shown via a negative-pressure hose. Thus the negative-pressure diaphragm  345  can be moved by suction out of one terminal position, shown in solid lines, to its other terminal position (locking position) represented by dashed lines. The negative-pressure diaphragm  345  is prestressed by a compression spring  336 , so that it returns to its outset position when the negative pressure has built back up again to normal pressure.  
      The exemplary embodiment shown in  FIG. 5  is once again similar to what is shown in  FIG. 1 ; once again, the drive mechanism  427  in the housing  426  is controlled by the pressure prevailing in the interior of the container  413 . However, instead of the diaphragm  40  of  FIG. 1 , a piston  440  is disposed in the cylindrical part  431  of the housing  426 , axially movably counter to the action of a compression spring  436 . The piston  440  is guided in pressuretight fashion along the inner wall of the cylindrical part  431  via a sealing ring  442 . The piston  440  is integrally provided with a concentric axial locking bolt  428  that is surrounded by the compression spring  436 , which is braced at one end on the piston  440  and at the other on an inner annular face of the cylindrical part  431 ; this annular face surrounds the through bore of the housing  426  through which the locking bolt  428  extends. The locking bolt  428  is pressed, counter to the action of the compression spring  436 , into an axial through opening  438  in the grip element  416  whenever the pressure in the interior of the container  413  exceeds a certain value. When the piston  440  has been displaced upward, the locking bolt  428  therefore prevents relative rotation between the grip element  416  and the container stub  412 . In this exemplary embodiment as well, the through opening  438  in the grip element  416  is continuous, or in other words accessible from the outside, so that professionals can still intentionally unlock and accordingly open the closure cap  411 .  
      The cylindrical part  431  of the housing  426  is covered on its inner end by a cap  432 , which fits over the cylindrical part  431  on the outside in detent-locking fashion. The cap part  432  is provided toward the bottom with a connecting opening  439 , which here is concentric in the middle and which makes it possible to transmit the pressure conditions in the interior of the container  413  to the axially movable piston  440 .  
      During engine operation, the coolant in the container  13 ,  113 ,  213 ,  313 ,  413  will heat up, so that the temperature and pressure will rise there. Because in the exemplary embodiments of  FIGS. 1, 2  and  5  the drive mechanism  14 ,  114  and  414 , respectively, is disposed directly in the container interior, then if there is a pressure increase in  FIG. 1 , in the half-section on the right, or  FIG. 5 , in the half-section on the left, the diaphragm  40  or the piston  440  will be deflected and moved axially in the direction of the arrow B, counter to the action of the compression spring  36  and  436  acting on the twist preventer  25  and  425 , respectively, so that the locking bolt  28  and  428  will engage the detent opening  38  and  438 , respectively. In the exemplary embodiment of  FIG. 2 , in the half-section on the right, the expanding material will be expanded because of the temperature increase, and thus the thermocapsule  140  expands axially in the direction of the arrow B, once again counter to the compression spring  136  acting on the twist preventer, and because of this expanding motion the locking bolt  128  enters the detent opening  138 .  
      The same is correspondingly true for the exemplary embodiment of  FIG. 3 , in which the temperature and pressure increase in the container  213  is derived indirectly from electrical engine data, for instance upon shutoff of the warm engine. Once again, the locking bolt  228  will engage the detent opening  238 .  
      In the exemplary embodiment of  FIG. 4 , whenever negative pressure is generated upon shutoff of the engine, the locking action that prevents the unscrewing of the closure cap  311  will occur once the locking bolt  328  has moved into the direction of the arrow C.  
      It is understood that whenever the operating position (temperature increase or pressure increase), which is picked up directly or indirectly, changes to the normal or outset position, the locking action is undone again, because the locking bolt  28 ,  128 ,  228 ,  328 ,  428  is returned under the influence of the compression spring  36 ,  136 ,  236 ,  326 ,  426 .  
      It is understood that in the exemplary embodiments of  FIGS. 3 and 4 , the location of the drive mechanism housings  226  and  326  can also be provided in some other way (on the outside instead of the inside, or on the inside instead of the outside, respectively). The same is correspondingly true for the location of the locking bolt.  
      Moreover, in all the exemplary embodiments, it is possible to provide a rockerlike force booster between the drive mechanism  26 ,  126 ,  226 ,  326 ,  426  and the locking bolt  28 ,  128 ,  228 ,  328 ,  428  that is deflected away from it.