Abstract:
A belay descender device for a rope comprising a earn mounted rotating on a fixed flange to perform locking of the rope when said rope is under tension, and a lever articulated on the cam to perform progressive unlocking of the rope with a geared-down effect at the beginning of unlocking travel of the lever. The operating lever comprises transmission means collaborating with a guide ramp of the flange to interrupt the mechanical link with the cam after an intermediate position of the lever has been passed resulting in freeing from said ramp outside the gearing-down area. The end of the guide ramp of the flange corresponds to the anti-panic position of the transmission means, enabling automatic locking of the canvas soon as the gearing-down area has been passed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a belay descender device for a rope comprising:
       a cam mounted rotating on a fixed flange to perform locking of the rope when said rope is under tension,   an operating lever or handle articulated on the cam to cause progressive unlocking of the rope with a geared-down effect at the beginning of the unlocking travel of the lever.       
 
         [0004]    STATE OF THE ART 
         [0005]      FIG. 1  represents a self-locking delay device for a rope described In detail in the document EP 2301631. It comprises a pulley in the form of a cam  10  arranged to cause locking of the rope when the rope is under tension, and an operating lever  11  collaborating with the cam  10  in order to cause progressive unlocking of the rope following a manual action on the lever  11  in the direction of the arrow F. The lever  11  acts on the cam  10  respectively with a geared-down effect In an initial part of its unlocking travel and with a direct driving effect in a final part of its travel. The relative movement of the cam  10  with respect to the movement of the lever  11  is lower in the initial part of travel than in the final part, which enables a precise adjustment of the braking force and of the running speed, of the rope in the initial part of the travel of the lever  11 . The cam  10  is articulated on a pivot-pin  12  of a fixed flange  13  and the operating lever  11  is articulated by a pivot-pin  14  on the cam  10 . The lever  11  comprises a bearing pin  16  designed to come into contact against a stop  16  of the flange  13 , said stop being located between the respective pivot-pins  12 ,  14  of the cam  10  and lever  11  when the latter is made to rotate in the unlocking direction. From this position, if the user pulls on the lever  11  in the clockwise unlocking direction, the cam  10  is urged in the clockwise direction with a geared-down force. With a low energy expenditure, the user can exert a large force on the cam  10  to overcome the force necessary to unlock the rope, and then to finely adjust the position of the cam  10  to modulate the clamping of the rope thereby finely adjusting the running speed of the rope. 
         [0006]      FIG. 1  represents the descender in a released position obtained when the user continues to pull on the lever  11  in the clockwise direction. The pin  15  disengages from the stop  16  and comes and presses on a wall of the cam  10 . The lever  11  is In a configuration without gearing-down of the driving, causing a direct and rapid movement of the cam  10  to the unlocking end-of-travel position. The cam  10  no longer blocks the rope so long as the lever  11  is kept in this position by the user. It can be noted that the pin  15  of the lever  11  remains pressing on the cam  10  establishing a permanent mechanical link between the cam  10  and the lever  11 . If the user panics during an uncontrolled descent along the rope, he is liable to grip the lever  11  pulling it strongly downwards. The rope is free and the user will not be able to stop to the detriment of his safety. 
         [0007]    The anti-panic function is known as such on conventional self-braking descenders as illustrated in the documents EP 2,777,772 and EP 2,018,894, but not on a belay descender device with gearing-clown for unlocking of the cam. 
       OBJECT OF INVENTION 
       [0008]    The object of the invention consists in providing a belay descender device on a rope that is able to be easily unlocked manually to improve the fluidity of descent along the rope, and that benefits from an automatic re-locking function in the event of the user panicking. 
         [0009]    The apparatus according to the invention is characterized in that the operating lever comprises transmission means collaborating with a guide ramp of the flange to interrupt the mechanical link with the cam after an intermediate position of the lever has been passed, resulting in freeing from said ramp outside the gearing-down area, and the end of the guide ramp of the flange corresponds to the anti-panic position of the transmission means enabling automatic locking of the cam as soon as the gearing-down area has been passed. 
         [0010]    According to a first embodiment of the invention, the transmission means comprise a drive rod articulated on the lever and able to slide along the guide ramp in said gearing-down area for unlocking the cam. 
         [0011]    According to a second embodiment, the transmission means are provided with a drive pivot-pin securedly attached to the lever and collaborating with a ratchet pivotally mounted on a pivot-pin of the flange, said ratchet being pushed by the drive pivot-pin against the guide ramp during the gearing-down area to trigger driving of the cam in. the unlocking direction. The pivot-pin is configured to come free from the ratchet in the intermediate anti-panic position. 
         [0012]    Preferentially, an overtravel of the lever in the unlocking direction beyond the intermediate position re-establishes the mechanical link with the cam and drives the latter directly without gearing-down. 
         [0013]    Resetting of the anti-panic function is performed manually by moving the operating lever in the opposite direction to place the transmission means back in their original position on the side of the guide ramp. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]    Other advantages and features will become more clearly apparent from the following description of two embodiments of the invention given for non-restrictive example purposes only and represented in the appended drawings, in which: 
           [0015]      FIG. 1  is an elevational view of a belay descender apparatus with an unlocking lever according to the prior art; 
           [0016]      FIG. 2  shows an exploded perspective view of a first embodiment of the belay descender according to the invention; 
           [0017]      FIG. 3  is a cross-sectional view of the belay descender on the cam side, and after the rope has been fitted; 
           [0018]      FIGS. 4A and 4B  are perspective views of the operating lever  11  equipped with a drive rod illustrated in two different positions; 
           [0019]      FIG. 4C  shows the apparatus in the looked state following tension of the rope, the lever occupying a folded position near the flange; 
           [0020]      FIGS. 5 and 6  represent partial cross-sectional views of the lever when progressive unlocking of the cam is performed with a geared-down force; 
           [0021]      FIG. 7  illustrates freeing of the rod with interruption of the mechanical link between the lever and the cam, causing automatic relocking of the apparatus; 
           [0022]      FIG. 8  represents an overtravel of the unlocking lever to re-establish the mechanical link with the cam enabling the user to be able to unlock the cam manually without gearing-down; 
           [0023]      FIGS. 9 to 12  show the successive phases of manual reloading of the lever to reactivate the anti-panic function after the rod has come free; 
           [0024]      FIGS. 13 to 16  show cross-sectional views of a second embodiment of the invention, which is illustrated in the course of the geared-down unlocking cycle up to the anti-panic position; 
           [0025]      FIGS. 17 to 19  show the different phases of manual resetting of the anti-panic function of the second embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]    With reference to  FIG. 2  illustrating an exploded perspective view of a first belay descender D 1  according to the invention, the fixed flange  13  for fitting the rotary cam  10  and the operating lever  11  in the form of a handle articulated on the cam  10  by the pivot-pin  14  can be seen. The cam  10  and operating lever  11  are arranged on each side of the flange  13 . The bearing pin  15  of the device of  FIG. 1  of the prior art is replaced by a drive rod  20 , and the direct stop  16  is not provided and is replaced by a guide ramp  21  located along the edge of the flange  13 . The rod  20  is articulated on the lever  11  by means of a pivot-pin  22 , and is kept in position by a spring (not shown). The flange  13  is provided with a recess  23  allowing passage of the rod  20  when if moves along the guide ramp  21  after actuation of the lever  11  in the unlocking direction. The recess  23  is delineated at its top part by the guide ramp  21 . The cam  10  comprises a first aperture  24  for passage of the pivot-pin  12  fixed in a hole  26  of the flange  13 , and a second aperture  25  for fixing the pivot-pin  14  of the operating lever  11 . A second flange  27  is arranged opposite the first flange  13  and collaborates with a spacer  28  to keep the rope in place. The second flange  21  can be fixed or rocking. For unlocking the rope, the cam  10  presses the rope against a braking surface  29 , which is provided on a stud  30  inserted and secured by a screw  31  between the two flanges  13 ,  27 . The two flanges  13 ,  27  are provided with holes  33 ,  34  for hooking an attachment (not shown). 
         [0027]      FIG. 3  shows the descender on the side of the cam  10 , after a rope  32  has been fitted. The cam  10  is mounted eccentric on the pivot-pin  12  and is in the form of a pulley around which a loop of the rope  32  is wound. 
         [0028]      FIGS. 4A and 48  represent the operating lever  11  equipped with the drive rod  20 , which can pivot around its pivot-pin  22 . The latter is threaded into a blind hole of the lever  11 , near the circular aperture  36  through which the pivot pin  14  of the lever  11  passes. A torsion spring  36  ( FIG. 2 ) is threaded coaxially on the pivot-pin  14  inside the aperture  35  to bias the cam  10  to the unlocking position. 
         [0029]    Operation of the descender belay according to the invention is illustrated with reference to  FIGS. 4C and 5-12 . 
         [0030]    When the rope  32  is under tension, either due to the user&#39;s weight when used as a descender, or when used for belaying by the traction effect exerted by a lead climber to be belayed, the cam  10  is urged in rotation around the pivot-pin  12  to the locked position. The rope  32  is jammed by cam  10  against the braking surface  29  so as to stop any downward movement of the user. The operating lever  11  is folded completely to the left, near the fixed flange  13  (see  FIG. 4C ). 
         [0031]    To release this locked position when the rope  32  is under tension, the user unfolds the lever  11  by rotating it in the clockwise direction. In  FIG. 5 , the rod  20  presses on the ramp  21  which defines the gearing-down area for driving the cam  10  in the unlocking direction with a geared-down force. Rotation of the lever  11  results in rotation of the cam  10  in a predefined ratio, for example 1/3. 
         [0032]    in  FIG. 6 , continued movement of the lever  11  in the direction of the arrow F drives the rod  20  which will slide along the guide ramp  21 . So long as the rod  20  remains on the ramp  21 , the user will be able to adjust the degree of jamming of the rope and control the speed of descent in descender mode. 
         [0033]    In  FIG. 7 , if the rod  20  reaches and passes the end of the ramp  21 , it is ready to come free from the flange  13  so as to interrupt the mechanical transmission link between the lever  11  and cam  10 . The latter, being released, will be automatically returned to the unlocking position of the rope by the biasing action of the torsion spring  36 . This case can occur when the user pulls very strongly on the lever  11  in the unlocking direction, &gt;t is the anti-panic function which automatically relocks the rope  32 , beyond the gearing-clown area after the rod  20  has come free from the ramp  21 . 
         [0034]    In  FIG. 8 , after an overtravel of the lever  11  in the direction of the arrow F, the rod  20  comes into engagement against a stop  37  of the cam  10 , which re-establishes the mechanical link enabling the user to be able to unlock the cam  10  and to descend without gearing-down, if he does not know how to reset the mechanism, and to reactivate the anti-panic function. 
         [0035]      FIGS. 9 to 12  represent the different phases of manual resetting to reactivate the anti-panic function after the rod  20  has come free. 
         [0036]    The lever  11  simply has to be moved in the counterclockwise direction indicated by the arrow R ( FIG. 9 ), resulting in pivoting of the rod  20  around its pivot-pin  22  when it is pressing on the flange  13  ( FIG. 10 ). 
         [0037]    In  FIG. 11 , the rod  20  retracts passing over the nose  38  of the flange  13  and comes back to place itself in the original position inside the ramp  21  of the flange  13  due to the presence of a spiral spring (see  FIG. 12 ). 
         [0038]      FIGS. 13 to 19  show a second embodiment of a belay descender D 2  according to the invention. Most of the pasts are identical with the same reference numerals, only the means for implementing the anti-panic function are different compared with those of the above-mentioned device D 1 . 
         [0039]    The rod  20  of the device D 1  of  FIGS. 2-12  is replaced by a drive spindle  50  securedly attached to the lever  11 , said spindle being designed to collaborate with a ratchet  51  mounted pivoting on a pivot-pin  52  of the flange  13 . The ratchet  51  is preferably mad(c) from stainless steel enabling a contact with the pivot-pin  50  with a high endurance. 
         [0040]    At the beginning of the clockwise travel of the lever  11  (arrow F,  FIGS. 13 and 14 ), the pivot-pin  50  pushes the ratchet  51  up against the ramp  21  of the flange  13  to trigger driving of the cam  10  in the unlocking direction. The pivot-pin pin  60  is advantageously surrounded by a tube, for example made from stainless steel, to improve sliding of the pivot-pin  50  on the ratchet  51 . The force take-up area between the ratchet  51  and the ramp  21  of the flange  13  enables a geared-down unlocking of the cam  10  when the descender D 2  is under load. 
         [0041]    In  FIG. 15 , continued movement of the lever  11  In the direction of the arrow F positions the pivot-pin  50  at the right-hand end of the ratchet  51 , ready to come free to interrupt the mechanical link between the lever  11  and cam  10 . This is the anti-panic position in which the released cam  10  automatically blocks the rope  32  following freeing of the pivot-pin  60  ( FIG. 18 ). If the user continues rotation of the lever  11  in the direction F, the pivot-pin  50  comes up against the stop formed by the cam  10  and drives the latter directly without gearing-down. This operation enables slack to be given when a user is to be descended in top-rope manner in the absence of tension on the rope. 
         [0042]    Resetting of the anti-panic function is performed by moving the lever  11  in the opposite direction to replace the drive pivot-pin  50  in its original position by means of the spring-loaded ratchet  51 . For this the lever  11  simply has to be moved in the counterclockwise direction of arrow R. At the beginning of resetting, the reaction of the pivot-pin  50  on the curved surface of the ratchet  51  causes withdrawal thereof ( FIGS. 17 and 18 ). The drive pivot-pin  50  of the lever  11  can thus return to its original position ( FIG. 19 ), with the anti-panic reset.