Abstract:
A line clamp or stopping apparatus includes a housing one part of which serves to clamp or wedge a line subjected to high tension upwards of ten tons. The other part of the housing controls the first part. An eccentric wheel rotates freely within the first part in response to movements of the line and is guided within a space or gap between the wheel and a braking element. The control includes a toggle joint that applies significant forces on the brake when a safety is removed and a control lever is in a neutral or locking position. When the control lever is moved to the open or unlock or release position the toggle joint snaps and released the brake to increase the gap in the line receiving space to allow free movement of the line. A hydraulic brake can be used in place of the mechanical toggle joint.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to line clamping devices and, more specifically, to a high tension line clamp with a quick release mechanism. 
   2. Description of the Prior Art 
   It is frequently necessary to control a line by either arresting or stopping its motion or releasing it. On sailing vessels, for example, lines are used to raise and control sails and other operating units often under heavy loads. The same line may first be lightly loaded, and then as the tension required increases, the use of a winch is necessary. To allow one winch to be used for several lines, of the same or varying sizes, a sheet or line stopper is provided for each line. When out of engagement, the line stopper permits the line to run in both directions. In an engaged position, the line runs under light pressure in one direction only. It is therefore possible to haul a line in by hand without slipping as a self-locking action prevents line movement of the line in the opposite direction. As the load increases, a winch is used to set the line in the desired position as control becomes difficult by hand. With the line stoppers presently available, although the line may be taken off the winch and still be held by the line stopper, it is impossible to release the line without the use of a winch to hold the load while the line stopper is released. In sailboat racing, putting a line on a winch in order to effect a release of the line stopper is time consuming as well as tying up a winch which may be necessary for another control function. Also, the line stopper tends to contact and abrade a line on its release under load even using a winch to help effect such a release. 
   The prior art is replete with braking mechanisms for arresting or releasing a line under tension. As suggested, such lines are frequently used to hoisting and trimming of sails in which the line may be subjected to tensions ranging from low to extremely high tensions up to and even exceeding ten tons. 
   A common mechanism for arresting a line includes a cylindrical surface mounted to exhibit an eccentric braking surface in relation to a fixed abutment surface so that movement of the eccentric braking surface can vary or adjust a gap through which the line is guided. When the gap is sufficiently reduced, the line is wedged between the braking and abutment surfaces. Normally, continued tension on the line in the same direction increases the wedging effect and thereby the lock on the line. One example of such a rope holding device is disclosed in U.S. Pat. No. 3,835,507, which shows a cylindrical cam mounted for rotation on a pin to cause the circumferential gripping surface to provide a variable line gap when the cam is rotated. A U-shaped base member having legs with a pivot pin mounted therein is adapted to be anchored on a sailboat. A cam mechanism includes an inner element having a handle attached thereto which is eccentrically mounted for pivotal movement around the pivot pin. A movable outer element is positioned for pivotal movement and a rotational movement on the eccentrically mounted inner element. One or more springs are mounted between the inner and outer elements of the cam mechanism which are acted on when relative movement takes place between the elements. The spring is compressed when the handle is pivoted placing the outer member in locking engagement with the line in the load direction which locking action is increased with increasing load; while allowing the outer member to rotate or float over the line in the other direction. Each release of the load direction is effected by raising the handle. The line stopper can be released under heavy load because the outer element holding the line rotates in the same direction the line is running, the line will not be abraded thereby limiting line wear. The line stopper may be mounted either vertically or horizontally. 
   A disadvantage of existing rope holding or stopping devices is that they require substantial forces to be applied to release the line after it has been locked. Thus, once the line tension causes the eccentric cam surface to close a gap for the line and wedges it to stop it and lock it continued tension on the line in the same direction tends to decrease the gap even further with attendant increased holding pressure on the line. Releasing the line from its wedged condition can be effected by reversing the process and increasing the size of the gap through which the line extends. Clearly, this can be done in one of two ways. One or the other of the wedging surfaces must be moved away from the other opposing surface so that the gap is increased and the line is again permitted to move. As suggested, the prior art devices have typically used a fixed abutment surface that always remains stationary. Therefore, the only way to increase the gap is to move the surface on the eccentric cam in a direction opposite to the initial direction that caused the cam to lock the line. However, this is not always an easy or quick task. The reason for this is that the tension in the line can be so high that applying an opposing tension on the other end of the line may be difficult if manually attempted. Application of a tension greater than the tension at the opposing end of the line could rotate the eccentric cam in the releasing position with attendant increase in the gap. This approach, however, becomes impractical when the tensions in the line are extremely high. For this reason, a winch must at times be used to overcome very high tensions in the line in order to reverse the direction of movement of the eccentric cam surface and thereby the size of the line receiving gap. In some cases, a handle or lever is used that is attached to the eccentric cam that allows a user to obtain mechanical advantage in moving or rotating the eccentric cam to an unlocking position. See, for example, U.S. Pat. No. 4,425,862 for a sail line stopper that uses a handle that cooperates with the cam. Unlocking the line using the stopper still requires significant effort. 
   SUMMARY OF THE INVENTION 
   Accordingly, it is an primary object to provide a line clamping device that does not possess the disadvantages of like prior art devices. 
   It is another object of the invention to provide a line clamping device that is simple in construction and economical to manufacture. 
   It is yet another object of the invention to provide a line clamping device that is easy to use. 
   It is still another object of the invention to provide a line clamping device that allows easy and rapid clamping of lines that are tensioned upwards of ten tons. 
   It is a further object of the invention to provide a line clamping device that requires little or no manual force to control lines subjected to significant tensions. 
   It is still a further object of the invention to provide a line clamping device of the type under discussion that can be set or programmed to control a line under tension. 
   In order to achieve the above and other objects a line clamping device includes clamping means for selectively clamping a line subjected to tension. Releasing means is provided for releasing the line by application of an insignificant force substantially unrelated to the tension in the line. Preferably, the release of the line is rapid and with little or no force manual force applied. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention, together with further aspects, features and advantages thereof will be more clearly understood by considering the following description in conjunction with the accompanying drawings in which like elements bear the same reference numerals throughout the several views. 
       FIG. 1  is a top perspective view of a line clamping device in accordance with the present invention, showing a line to be controlled extending there-through; 
       FIG. 2  is similar to  FIG. 1  but showing a plurality of like clamping devices stacked to accommodate and control a plurality of lines; 
       FIG. 3  is an enlarged cross-sectional view of the clamping device shown in  FIG. 1 , taken along a longitudinal plane coextensive with the plane in which the line is arranged, showing a condition in which the line is free to move through the device in either direction and with the eccentric wheel positioned to minimize braking or locking of the line; 
       FIGS. 4 and 5  are similar to  FIG. 3 , but showing the eccentric wheel rotated 90° and 180°, respectively, from the position shown in  FIG. 3 ; 
       FIG. 6  is similar to  FIGS. 3-5  but showing a manual control moved to the locking position while the eccentric wheel is in the 180° position; 
       FIG. 7  is similar to  FIG. 6  in which the eccentric wheel has moved to the original reference or 0° position to enable locking; 
       FIG. 8  is similar to  FIG. 7  except that the eccentric wheel has moved to a position between 90° and 180° to wedge or lock the line against further movement in the direction in which it had been moving causing the eccentric wheel to rotate in a clock-wise direction as viewed in the Figure; 
       FIG. 9  is similar to  FIG. 8  but showing a safety moved to a position that allows the device to become unlocked for eventual release of the line; 
       FIG. 10  is similar to  FIG. 9  but showing the manual control lever moved to a line unlocking or releasing position and showing the initial phases of the release of the line; 
       FIG. 11  is similar to  FIG. 10  but showing a further progression of the unlocking or releasing of the line and the return of the control lever to the neutral position; 
       FIG. 12   a  illustrates a modified version of the toggle linkages shown in  FIGS. 3-11  that provides a force component, when in the locked condition, that prevents the device from inadvertently moving from the locked to an unlocked condition. 
       FIG. 12   b  is a force diagram of the forces generated with the modification shown in  FIG. 12   a;    
       FIG. 13  is a partial cross-section through the device shown in  FIG. 3 , taken along line  13 - 13 ; 
       FIG. 14   a  shows the levers or links forming the toggle joint; 
       FIG. 14   b  is a force diagram showing the forces generated at the pivot pin of the toggle joint and the component that promotes or aids the toggle mechanism to snap to the releasing position; and 
       FIG. 15  illustrates another embodiment of the line clamping device of the invention in which the toggle joint wedging mechanism is replaced by a hydraulic device. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring first to  FIG. 1 , a line clamping or locking device in accordance with the invention is generally designated by the reference numeral  10 . 
   The device  10  serves to selectively clamp, lock, stop or arrest a line  12  while it is under tension and moving in either direction M or N. 
   The device  10  includes a housing or case  14  shown to be relatively flat and elongate in one direction in the general plane of the housing. However, it will be evident that the specific configuration of the housing or case is not critical and any convenient or suitable shape or configuration may be used that is consistent with the mounting and operation of the elements or components contained therein to be described. 
   Generally, the housing or case or chassis  10  includes or defines two sections. The first is a wedging or locking section  16  through which the line  12  to be controlled enters and exits the housing through suitable openings  20 . The other part of the housing defines a control portion  22  which controls the actions that take place in the wedging or locking section  16 . The control portion  22  includes a manual control mechanism  24  that extends through a slot  26  and includes a rod or shaft  30  that extends through the slot  26  and may be provided with a knob or gripping portion  32 . The slot  26  is generally straight and provided with right angle recesses or detents  26   a  and  26   b  at the two respective ends of the slot, the recess  26   a  serving as a line releasing position for the rod  30  that promotes releasing of the line  12  while the recess  26   b  serving as a locking position for the rod that promotes the clamping or locking or stopping of the line, as will be more fully described. It will become evident that the specific configuration of the slot  26  and the use of recesses or detents  26   a ,  26   b  is not critical and any other and suitable mechanism, electro-mechanism or circuit may be used to establish and maintain the desired condition of the control portion  22 . 
   In  FIG. 2 , a plurality of clamping devices  10 ,  10 A and  10 B are shown stacked to make efficient use of space while accommodating three lines  12 ,  12 A and  12 B. Each of the devices may be similarly constructed and, accordingly, may be provided with independent control portions  22 ,  22 A and  22 B. These units may be secured to each other in any conventional way. The construction and operation of each of the units is the same and the description that follows in connection with  FIG. 3  is applicable to each of the units. 
   Referring to  FIGS. 3 and 12 , one preferred embodiment, by way of example, will now be described in detail. The wedging or locking part  16  of the clamping device includes a fixed pin or rivet  34  that, referring to  FIG. 2 , may also be used to secure two or more of the units to each other. The pin or rivet  34  is fixed to the upper and lower walls of the housing  14 , as viewed in  FIG. 1 , and defined a center or “axis” of rotation  36 . Rotatably mounted on the pin or rivet  34  is a bearing  38  that can freely rotate about the fixed center or “axis”  36 . Mounted on the bearing  38  is an eccentric wheel  40  whose “axis” is offset from the center or “axis”  36  an amount C. The eccentric wheel is preferably provided with notches  42  about its outer circumference forming arcuate surfaces  44  in the resulting teeth or projections  47 . The depth of the arcuate surfaces define a radially innermost dimension  44 ′ for accommodation the generally round or circular cross-section of the line  12 . A reference point  48  designated “R” is shown to facilitate the description of the wheel  40  and its operation. As will be clear, with this arrangement, the wheel  40  has a maximum radial dimension at  48  along the radius passing through the point R while the minimum dimension is at the diametrically opposite side at  50 . 
   As will become evident, the stopping, locking or clamping action on the line  12  occurs when it is wedged within gap or space  50  between the wider side  48  of the wheel  40  and an opposing surface to be described. The eccentricity C, generally corresponds to the differences between the effective radii extending through the wide and narrow portions of the wheel  48 ,  50 , respectively. 
   A shoe or pad  56  forms the opposing surface  58  that with the wheel  40 , defines the gap  50 . It will be clear that the gap  50  may be decreased by rotating the wheel  40  from the position shown in  FIG. 3  and minimized when the wheel has rotated 180°. Also, the gap  50  may be decreased by moving the surface  58  to the right, as viewed in  FIG. 3 . The gap  50  may, correspondingly, be increased by reversing these movements. 
   The shoe or pad  56  is provided with a heel  60  that engages a piston  62 , by being received or in contact with an axial conforming recess  64 . However, different arrangements can be used to couple the axial movements of the piston  62  to the shoe  56 . 
   The piston  62  is dimensioned to be slidably mounted for axial movements between end walls  14   a ,  14   b , and is provided on the side closest to the end wall  14   b  with an axial shaft  66  defining an end surface  68  facing the control portion  22  and slidable received within an axial channel  72  in a transverse wall  70 . The wall  70  is generally annular with the central or axial hole  72 , with the axial thickness of the wall  70  not necessarily uniform as evidenced by the thinner wall portion  74  as compared to the upper wider portion. It will also be clear that the wall need not be annular but separate wall portions or transverse members may be provided as long as they perform the same or similar functions to the walls  70 ,  74 . 
   The wall  70  exhibits a transverse surface  76  facing the piston  62  and spaced from the facing surface of the piston a distance  78  in which biasing members may be positioned to bias or urge the piston  62  and therefore the shoe  62  to move towards the right, as viewed in  FIG. 3  or towards the eccentric wheel  40  to thereby lessen the gap  52 . Towards this end, the piston may be provided with an axial cavity  80  in the direction of the surface  76  with a compression spring extending there between as shown. Similarly, a compression spring  84  may be lodged between the surface  76  and the surface  86  of the piston as shown. As indicated, both springs  82 ,  84  will urge the piston  62  and the shoe  56  to move towards the wheel  40  to normally tend to wedge the line, with the position of the wheel  40  permitting, and allowing the piston  62  to reciprocate along the axial direction  88  when there is no interference from the control section  22 . Thus, as the line  12  is pulled in the upward direction M, as viewed in  FIG. 3 , the eccentric wheel  40  rotates about the center or “axis”  36  causing the line and the shoe  56  in contact with it to likewise reciprocate or fluctuate along the axial direction  88  with the wider part  48  of the wheel urging the line and shoe towards the left against the action of the springs  82 ,  84 . 
   Mounted at the other end of the housing  14  is a fixed pin or post  90  that can be in the form of a rivet that serves as a pivot, as to be described, and can also be used to secure two or more of the devices, as suggested in  FIG. 2 . Pivotally mounted at one end on the post or pin  90  is a link  92  that has the other end thereof pivotally secured to a moveable pin  94  to a locking rod of bar  96 . The rod  96  has an end surface  100  that can substantially correspond to the surface  68  so that these two surfaces can contact and abut against each other, as to be described. 
   Normally, with no other elements, the link  92  could pivot about the post  90  and the rod  96  could pivot about the pin  94 . However, a post  102  is provided in proximity of the link  92  as shown, with a cam  104  pivotally mounted on the post  102  controlled by the control lever  24  and having a cam surface  106  configured to either maintain the link  92  aligned with the “axis” A or displaced slightly from that “axis”, as to be described. Also, there is also provided a spring loaded plunger or pusher  108  mounted on the cam  104  and arranged to either allow free pivotal movements of the locking rod  96  about the pin  94  or to urge the locking rod to move into alignment with the link  92  and the “axis”. 
   A leaf or coil spring  110  is provided on a post  112  proximate to the wall  70  that has one leg  110   a  abutting against the surface  89  and the other leg  110   b  having its end contacting and pushing against the locking rod  96  to urge it in a clockwise direction, as viewed in  FIG. 3 . 
   The side wall  14   c  is provided with an opening  114  through which a safety lever  116  can move. The safety lever  116  has a rod  118  pivotally mounted on a post  120  with one end  122  of the lever being dimensioned to be received within the housing  14  and into contact with the end of the link  92  on which the pin  94  is mounted. A knob or gripping member  124  may be provided to facilitate manual gripping and control of the rod  118 . When the rod is positioned as shown in  FIG. 3 , generally transverse to the “axis” A it is dimensioned to abut against the link  92  and maintain it aligned along the “axis” A or at least prevent it from rotating in a counter-clockwise direction beyond the “axis” aligned position. Thus, when the safety lever  116  is in the position shown in  FIG. 3 , the link must remain aligned with the “axis” A irrespective of the pushing action by the cam surface  106  on the control lever  24 . 
   A leaf or coil spring  126  is mounted on a post  120  as shown with one of the legs  126   a  acting against the upper part of the rod  118  proximate to the knob  124  and the other leg  126   b  acting against the outer surface of the side wall  14   c  so that the spring  126  normally tends to urge or bias the rod  118  in a clockwise direction about the post  120 , as viewed in  FIG. 3 . Thus the spring  126  normally urges or biases the safety lever  116  to move to the “safety” position in which the link  92  is maintained in the position shown. 
   A further spring  128 , also shown as a leaf or coil spring, is mounted on a post  130  with one leg  128   a  abutting against the inner surface of the end wall  14   b  while the other leg  128   b  acts directly on the link  92  normally urging the link  92  to rotate about the fixed post  90  in a clockwise direction into contact with the cam surface  106 . 
   The operation of the clamping devise will now be described in connection with  FIGS. 3-14 . In  FIG. 3 , the control portion  22  is set to allow the line  12  to move in either direction M or N. As the line moves through the devise the frictional engagement of the line with the wheel  40  causes the wheel to rotate either in a clockwise direction, if the line is moving in the direction M or in a counter-clockwise direction if the line moves in the opposite direction N. For purposes of the illustration it will be assumed that the line is tensioned and moves in the direction M. With the wheel  40  initially in the position shown in  FIG. 3 , the wheel  40  will initially move to the position shown in  FIG. 4 , point R having moved 90°, and subsequently to the position shown in  FIG. 5 , in with the point R has moved another 90° for a total of 180°. In doing so, the eccentric wheel has urged the line and the shoe  56  and the piston  62  to move to the left against the actions of the springs  82 ,  84 . However, because the piston shaft  66  can slide axially to the left without any resistance the gap or space  52  for the line remains substantially the same and the line is not wedged, stopped or arrested in any way. As the line keeps being pulled through the wheel  40  continues to be rotated and the eccentric nature of the wheel causes the line portion passing through the gap or space  52  to oscillate or reciprocate along the direction  88  of the “axis” A. This will continue until a decision is made to stop, arrest or clamp the line. 
   While the control lever  24  is in a “neutral” position in  FIGS. 3-5 , a user will have moved the lever to the lock or stop position in  FIGS. 6-8 , urging the cam  104  in a counter-clockwise direction and causing the plunger or pusher  108  to apply a sufficiently significant biasing force on the locking rod  96  to tend to rotate it in a counter-clockwise direction against the action of the leaf or coil spring  110 . In  FIG. 6 , although the resiliently-mounted plunger or pusher  108  is pushed into the cam  104  and a significant force is applied to the locking rod  96  the latter cannot initially respond to the force of the control lever  24  because of the initial extended position of the shaft  66  of the piston  62  which blocks the continued counter-clockwise rotation or pivoting of the locking rod. However, as soon as the eccentric wheel  40  rotates to move reference point R from the left to the right side of the center  36  the shoe  56  and the piston  62  return to their positions shown in  FIG. 3  and the continued biasing action of the plunger or pusher  108  moves the locking rod  96  into alignment with the “axis” A and into a co-extensive or co-axial alignment with the shaft  66 . The safety lever  116  prevents the locking rod to move beyond that aligned position. 
   It will be appreciated that as soon as the locking rod  96  is moved to the aligned position along the “axis” its end surface  100  becomes an interfering surface that prevents the shaft  66  and the piston  62  and the shoe  56  from unrestricted movements to the left, as viewed in the figures. Now, as the eccentric wheel  40  rotates from the position shown in  FIG. 7  to the position shown in  FIG. 8 , the eccentricity of the wheel again urges the line  12 , the shoe  56  and piston  62  to the left as they try to follow the increasing distance between the center  36  and the outer circumference of the wheel. However, because the locking rod is in place in alignment with the shaft  66  is stopped and the continued rotation of the wheel caused an increasing reduction in the size of the gap or space  52 . This causes a wedging effect and the line is abruptly stopped when the wheel is rotated to bring the point R between the positions shown in  FIG. 8  and  FIG. 6 . (90° and 180°). As will be understood to those skilled in the art, the link  92  and the locking rod  96  together form a toggle joint. Such a joint, formed of two arms or links, can be used to implement a “snap-action” when the links are moved out of alignment. However, when in alignment such arms or links can be used to apply significant pressures at both ends by forcing the arms or links into straight alignment when the ends of the arms or links are constrained or fixed in place. Here, one end of the link  92  is fixed because mounted on fixed post  90 , and the other end at surface  100  of the locking rod  96  likewise becomes constrained by the shaft  66 . Therefore, the system can absorb substantial internal longitudinal or axial pressures without altering the state of the mechanism. 
   In  FIG. 9 , the safety lever  116  has been moved by counter-clockwise rotation to remove the locking end  122  out of the housing  14  and out of proximity of the link  92 . Now, by manually moving the control lever  24  to the open or unlocking or unclamping position, as shown in  FIG. 10 , the cam surface  106  causes the link  92  to rotate in a counter-clockwise direction and breaking the alignment of the link  92  and the locking rod  96 . The resulting “toggle” action caused the levers to snap out of alignment due to the internal forces in the system and without application of any meaningful forces by the user. These strong forces stored in the system are sufficient to overcome the biasing forces of the springs  110  and  128 , and the locking rod  96  can move sufficiently to the left move the surface  100  out of contact with the surface  68  of the shaft  66  and the gap or space  52  is again allowed to enlarge or increase and the line allowed to move in the same direction to remove any wedging action on the line. As soon as the wheel is again permitted to rotate to the position shown in  FIG. 3 , and the control lever is again moved to the “neutral” position shown in  FIG. 11 , the springs  110  and  128  urge the link  92  and the locking rod  96  to clear the retracted shaft  66  and return to the unlocked positions shown in  FIG. 3 . This may again be repeated by moving the safety lever to the safety position shown in  FIG. 3  and the control lever moved to the locking position shown in  FIG. 6 . 
   It will be appreciated that the locking and unlocking of the line can be easily and rapidly effected by a user by exerting forces that are insignificant and have no bearing to the substantial tensions in the line that can be upward of ten tons. 
   In  FIGS. 12   a  and  12   b  a modified design is shown that prevents the unit, when in a locked condition, from inadvertently snapping out of alignment by slightly and thereby releasing the line even when such release is not desired. This safety feature is achieved by inclining the surfaces  68 ′ and  100 ′ of the shaft  66  and the locking rod  96 , respectively, out of a plane that is ninety degrees or normal to the “axis” A. The deviation out of such a normal plane is not critical but may be within the range of 0.5°-1.0°. This creates a force component F 6  that holds the locking rod  96  in a locked position even for small a angles of less than one degree and produces axial and normal force components F 5  and F 6 . The force component F 6  pushes the locking rod  96  against the surface  70 ′ of the wall  70  that prevents the locking rod  96  from accidentally moving downwardly (as viewed in the Figures) out of blocking axial alignment that would release the line  12 . Because of the large magnitudes of F 5  even small angles of a creates significant holding forces F 6 . 
   The toggle action or mechanism is one that can be used with the invention as it can withstand tremendously high forces. Referring to  FIGS. 14   a ,  14   b  the actions and forces that come into play can be seen. When the link  92  and the locking rod  96  are in alignment the forces F 1  and F 2  counter each other and no matter how high they are they cancel each other and they remain aligned. As soon as there is some instability and even the slightest break in the alignment, even at angles of β close to 180 a force component F 3  is formed that creates further instability and enhances the snap action to even greater misalignment. With the safety lever  116  out of the safety position such forces could cause the toggle to snap and the line rapidly released. 
   When there is no emergency condition that requires immediate release of the line  12  under high tension conditions but it is desired to make an adjustment of the line  12 , the control lever  24  can be moved to the neutral position as shown on  FIG. 3 . The line  12  can be pulled in the opposite direction (direction “N” in  FIG. 1 ) until the  FIG. 3  position of the wheel  40  is reached. In this position the force F 6  will be zero and spring  110  will move the locking rod  96  out of the contact with the piston shaft  66 . The shoes  56  and piston  62  will be able to move back and forth during on adjustment process. After necessary adjustment the control lever  24  can be moved to locking position. After the adjustment the force will be zero the line will be locked as shown on  FIG. 8   
   As suggested, the mechanical toggle mechanism is one way to effectively stop the piston  62  and therefore the shoe  56  from unrestricted movements the full or maximum stroke to the left or movements that correspond to the eccentricity of the wheel  40 . However, other approaches are possible and contemplated. Thus, for example, referring to  FIG. 15 , a clamping device is shown in which the wedging part  16  is the same as in the previous embodiment. However, the stopping part has been changed, with the toggle arrangement replaced with a hydraulic system. Here, the housing includes a sealed chamber  150  filled with hydraulic fluid  160 . A piston  162  is slidably arranged within the chamber to be moveable in a reciprocating fashion in the direction of the “axis” A. A shaft  164  is attached to and moves with the movements of the piston, the shaft  164  having an end surface  166  that corresponds to the surface  100  on the locking rod  96 . The shaft  164  is slidably arranged within a bore  168  arranged along the “axis” and any suitable seal  170  may be provided to prevent fluid from escaping the chamber  150  into the chamber housing the piston  62 . A compression spring  176  is arranged between the piston  162  and the end of the chamber  150  to urge the piston  162  and the shaft  164  to normally slide or move towards the right and likewise cause the piston  62  and the shoe  56  to follow. Two through holes  172 ,  174  communicate the chamber  150  with a control valve  178  that can be manually or electrically operated to regulate the flow of fluid from one side of the piston  162  to the other. When the valve  178  is open the fluid can freely flow from one side to the other as the piston  62  and the shoe  56  follow the contour of the eccentric wheel. However, as soon as the piston  162  and shaft  164  are locked in position in their right-most position (this can be effected by a suitable sensor) the movements of the shoe  56  and the piston  62  are restricted and wedging of the line can be effected as previously. 
   While manual controls have been described, it will also be understood that remote or wireless controls of the “blocking” elements can be used to thereby cause locking, wedging or stopping of the line by a remote user or even by a programmed controller that senses when such action should take place and a blocking element be interposed that will result in wedging or stopping of the line. 
   Since other changes and modifications varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the examples chosen for purposes of illustration, and includes all changes and modifications which do not constitute a departure from the true spirit and scope of this invention as claimed in the following claims and equivalents thereto.