Abstract:
Carabiners have a gate that is movable between a closed position and an open position, and a locking member that prevents opening of the gate when the gate is in the closed position and the locking member is in a locked position. The locking member is biased to the locked position. The locking member is also movable to a retainable unlocked position. Methods of manufacturing such carabiners include configuring a locking member of a carabiner to move between a locked position and a retainable unlocked position, and biasing the locking member to the locked position. Methods of using a carabiner include positioning a locking member in a retainable unlocked position, opening a gate of the carabiner, and allowing the locking member to at least substantially automatically move to a locked position as the gate is closed.

Description:
TECHNICAL FIELD 
       [0001]    Embodiments of the invention relate to carabiners, to methods of manufacturing carabiners, and to methods of using carabiners. 
       BACKGROUND 
       [0002]    Carabiners are ring-like devices that have a gate that can be opened and closed to allow, for example, a bight of rope to be passed through the gate such that the rope extends through the carabiner without having to thread an end of the rope through the carabiner. Carabiners are used in various applications. Carabiners are often used in outdoor recreational activities such as rock climbing, mountaineering, and sailing. Carabiners are also employed, however, in non-recreational applications such as, for example, rescue operations and military applications. 
         [0003]    Generally, a carabiner has a C-shaped ring body having a first end and a second end with an opening therebetween. A gate is pivotally attached to one end of the ring body and extends across the opening in the ring body to the other end of the ring body, such that the gate may be selectively opened to allow articles to pass through the opening between the ends of the ring body, or closed to prevent articles from passing through the opening between the ends of the ring body. The gate may be biased to the closed position using, for example, a spring positioned and configured to urge the gate to the closed position. 
         [0004]    To avoid inadvertent opening of the gate of a carabiner, it is known in the art to provide a locking sleeve on the gate. The locking sleeve may be movable between a locked position and an unlocked position. In the locked position, the locking sleeve prevents the gate from moving from the closed position to the open position, but allows the gate to move from the closed position to the open position when the locking sleeve is in the unlocked position. In some carabiners, the locking sleeve is threaded onto the gate, such that the locking sleeve is rotated in a first direction about the gate by a user to move the locking sleeve into the locked position, and rotated in an opposite, second direction about the gate by the user to move the locking sleeve into the unlocked position. In other carabiners, the locking sleeve is configured to slide in a longitudinal direction relative to the gate between the locked and unlocked positions. In such embodiments, the locking sleeve may be biased to the locked position using, for example, a spring positioned and configured to urge the locking sleeve to the locked position. 
         [0005]    Examples of carabiners that include locking sleeves are disclosed in, for example, U.S. patent application Ser. No. 11/291,493, filed Dec. 1, 2005 (published Jun. 29, 2006 as United States Patent Application Publication No. U.S. 2006/0137151 A1); U.S. patent application Ser. No. 11/827,380, filed Jul. 10, 2007 (published Jan. 31, 2008 as United States Patent Application Publication No. U.S. 2008/0022497 A1); and U.S. Pat. No. 6,588,076 to Choate, which issued Jul. 8, 2003. 
       BRIEF SUMMARY 
       [0006]    In some embodiments, the present invention includes carabiners having a gate that is pivotally attached to a first end of a body and movable between a closed position and an open position, and a locking sleeve that is movable between a locked position and a retainable unlocked position. In the closed position, the gate extends from the first end to a second end of the body. The locking member is biased to the locked position, and is configured to prevent the gate from opening when the gate is in the closed position and the locking member is in the locked position, and to allow the gate to open when the gate is in the closed position and the locking member is in the retainable unlocked position. The locking sleeve is configured to move out of the retainable unlocked position when the gate is pivoted relative to the body of the carabiner beyond a threshold angle as the gate is opened. 
         [0007]    In additional embodiments, the present invention includes methods of manufacturing carabiners. A gate is pivotally attached to a first end of a body of a carabiner, and the gate is configured to pivot relative to the body between a closed position and an open position. A locking member is attached to at least one of the gate and the body of the carabiner. The locking member is configured to move relative to the gate between a locked position and a retainable unlocked position, and is biased to the locked position. The locking member is further configured to prevent the gate from opening when the gate is in the closed position and the locking member is in the locked position, and to allow the gate to open when the gate is in the closed position and the locking member is in the retainable unlocked position. The locking sleeve is configured to move out of the retainable unlocked position when the gate is pivoted relative to the body of the carabiner beyond a threshold angle upon opening the gate. 
         [0008]    In yet further embodiments, the present invention includes methods of using a carabiner in which a locking sleeve of a carabiner is positioned in a retainable unlocked position. A gate of the carabiner is opened while the carabiner is in the retainable unlocked position, the locking sleeve of the carabiner is moved out of the retainable unlocked position by pivoting the gate relative to a body of the carabiner beyond a threshold angle, and the locking sleeve is allowed to at least substantially automatically move to a locked position as the gate is moved to a closed position. 
         [0009]    These features, advantages, and aspects of particular embodiments of the present invention will be apparent to those in the art from a consideration of the detailed description set forth below when considered together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0010]    While the specification concludes with claims particularly pointing out and distinctly claiming that which is regarded as the present invention, the advantages of this invention may be more readily ascertained from the description of embodiments of the invention when read in conjunction with the accompanying drawings, in which: 
           [0011]      FIGS. 1A through 1C  illustrate an embodiment of a carabiner of the present invention and shows a gate of the carabiner in a closed position, and a locking sleeve of the carabiner in an a retainable unlocked position; 
           [0012]      FIG. 1A  is a side plan view of the carabiner; 
           [0013]      FIG. 1B  is an end plan view of the carabiner; 
           [0014]      FIG. 1C  is plan view of a side of the carabiner opposite that shown in  FIG. 1A ; 
           [0015]      FIGS. 2A through 2C  illustrate the carabiner of  FIGS. 1A through 1C , and shows the gate of the carabiner in an open position; 
           [0016]      FIG. 2A  is a side plan view of the carabiner; 
           [0017]      FIG. 2B  is an end plan view of the carabiner; 
           [0018]      FIG. 2C  is plan view of a side of the carabiner opposite that shown in  FIG. 2A ; 
           [0019]      FIGS. 3A through 3C  illustrate the carabiner of  FIGS. 1A through 1C  and  2 A through  2 C, and show the gate of the carabiner in a closed position, and the locking sleeve of the carabiner in a locked position; 
           [0020]      FIG. 3A  is a side plan view of the carabiner; 
           [0021]      FIG. 3B  is an end plan view of the carabiner; 
           [0022]      FIG. 3C  is plan view of a side of the carabiner opposite that shown in  FIG. 3A ; 
           [0023]      FIG. 4  is an exploded view of the gate, the locking sleeve, and a spring member of the carabiner shown in  FIGS. 1A through 1C ,  2 A through  2 C, and  3 A through  3 C; 
           [0024]      FIGS. 5A through 5C  illustrate another embodiment of a carabiner of the present invention; 
           [0025]      FIG. 5A  is a perspective view of the carabiner and shows a gate of the carabiner in a closed position and a locking sleeve of the carabiner in a retainable unlocked position; 
           [0026]      FIG. 5B  is a side plan view of the carabiner showing the gate in an open position and the locking sleeve moving out from the retainable unlocked position; and 
           [0027]      FIG. 5C  is side plan view like that of  FIG. 5B  and shows the gate in the closed position and the locking sleeve in a locked position. 
           [0028]      FIGS. 6A through 6C  illustrate another embodiment of a carabiner of the present invention; 
           [0029]      FIG. 6A  is a perspective view of the carabiner and shows a gate of the carabiner in a closed position and a locking sleeve of the carabiner in a retainable unlocked position; 
           [0030]      FIG. 6B  is a side plan view of the carabiner showing the gate in an open position and the locking sleeve moving out from the retainable unlocked position; and 
           [0031]      FIG. 6C  is side plan view like that of  FIG. 6B  and shows the gate in the closed position and the locking sleeve in a locked position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    The illustrations presented herein are not meant to be actual views of any particular material, apparatus, system, or method, but are merely idealized representations which are employed to describe the present invention. Additionally, elements common between figures may retain the same numerical designation. 
         [0033]    The present invention, in a number of embodiments, includes carabiners having a locking sleeve that can be retained in an unlocked position without application of force to the locking sleeve by a user, but that are biased to a locked position such that, as a user urges the locking sleeve out of the unlocked position, the carabiner substantially automatically moves to the locked position. 
         [0034]      FIGS. 1A through 1C ,  2 A through  2 C, and  3 A through  3 C illustrate an embodiment of a carabiner  100  of the present invention. As discussed in further detail below, the carabiner  100  has a generally C-shaped body  102 , a gate  110  that is movable between a closed position and an open position, and a locking sleeve  120  that is movable between a locked position and a retainable unlocked position.  FIGS. 1A through 1C  illustrate the carabiner  100  with the gate  110  in the closed position and the locking sleeve  120  retained in a retainable unlocked position.  FIGS. 2A through 2C  illustrate the carabiner  100  with the gate  110  in an open position and the locking sleeve  120  in the process of being urged out from the retainable unlocked position.  FIGS. 3A through 3C  illustrate the carabiner  100  with the gate  110  in the closed position and the locking sleeve  120  in the locked position. 
         [0035]    Referring to  FIG. 1A , the carabiner  100  includes a generally C-shaped body  102  having a first end  104  and a second end  106  that are separated from one another by an opening that is not visible in  FIGS. 1A through 1C , as the opening is closed by the gate  110  in  FIGS. 1A through 1C . The generally C-shaped body  102  may be formed from and comprise a metal or metal alloy such as, for example, an aluminum-based alloy, an iron-based alloy, a nickel-based alloy, a cobalt-based alloy, a magnesium-based alloy, a titanium-based alloy, etc. In other embodiments, the generally C-shaped body  102  may be formed from and comprise a polymer material, or a composite material such as, for example, a fiber or whisker (e.g., carbon fiber) reinforced polymer (e.g., epoxy) or metal alloy material. 
         [0036]    The first end  104  of the body  102  is configured for attachment to an end of the gate  110  (the lower end from the perspectives of  FIGS. 1A through 1C ), and the second end  106  of the body  102  is configured to interact with another, opposite end of the gate  110  (the upper end from the perspectives of  FIGS. 1A through 1C ). 
         [0037]    The lower end of the gate  110  may be pivotally attached to the first end  104  of the body  102  using, for example, a pin member  130  (e.g., a rivet) that extends through the first end  104  of the body  102  and through the lower end of the gate  110 . As shown in  FIG. 1A , the pin member  130  may include a head  132  that projects laterally outward from the first end  104  of the body  102  on one side thereof (e.g., the side shown in  FIG. 1A ). The pin member  130  may be substantially flush with the surface of the first end  104  of the body  102  on an opposite side of the body  102  (e.g., on the side shown in  FIG. 1C ). The head  132  of the pin member  130  may interact with features of the locking sleeve  120 , as discussed in further detail herein below. 
         [0038]    The second end  106  of the body  102  may include what is referred to in the art as a “nose”  108  that is configured to be received within a receptacle  112  ( FIG. 4 ) formed in the upper end of the gate  110  when the gate  110  is in the closed position. An aperture  128  is formed in the upper end of the locking sleeve  120  to allow the nose  108  to be received into the receptacle  112  of the gate  110  as the gate  110  moves from the open position into the closed position, but the upper end of the gate  110  is configured to preclude the nose  108  from passing through the upper end of the gate  110 . For example, the receptacle  112  in the gate  110  does not extend entirely through the gate  110 . As a result, the gate  110  is only capable of pivoting inward into the area enclosed by the C-shaped body  102  and is precluded from pivoting outward relative to the C-shaped body  102 . 
         [0039]    As shown in  FIG. 1A , the locking sleeve  120  is carried by, and positioned concentrically about, the gate  110 . The locking sleeve  120  and the gate  110  are configured such that the locking sleeve  120  can rotate circumferentially about the gate  110 , and such that the locking sleeve  120  can slide longitudinally along the gate  110 . 
         [0040]      FIG. 4  is an exploded view of the gate  110 , the locking sleeve  120 , and a spring member  138  that is disposed between the gate  110  and the locking sleeve  120 . The spring member  138  is hidden from view in  FIGS. 1A through 1C . In the embodiment shown in  FIG. 4 , the spring member  138  is a torsion spring that acts on both the gate  110  and the locking sleeve  120  in such a manner as to bias the locking sleeve  120  toward the first end  104  of the body  102  (the downward direction in the perspectives of  FIGS. 1A through 1C ), and also to rotationally bias the locking sleeve  120  in a counter-clockwise rotational direction about the gate  110  (when looking at the end surfaces of the gate  110  and locking sleeve  120  proximate the second end  106  of the body  102 ). 
         [0041]    Referring again to  FIG. 1A , in the absence of an applied external force, the spring member  138  forces the locking sleeve  120  toward the first end  104  of the body  102  (in the downward direction in the perspectives of  FIGS. 1A through 1C ) to cause a lower surface  121  of the locking sleeve  120  to abut against the head  132  of the pin member  130 , which prevents the locking sleeve  120  from further movement toward the first end  104  of the body  102 . A user, however, can apply an external force to the locking sleeve  120  to cause the locking sleeve  120  to slide toward the second end  106  of the body  102  (in the upward direction in the perspectives of  FIGS. 1A through 1C ). 
         [0042]    Also, in the absence of an applied external force, the spring member  138  ( FIG. 4 ) forces the locking sleeve  120  to rotate in the counter-clockwise direction (when looking at the end surfaces of the gate  110  and locking sleeve  120  proximate the second end  106  of the body  102 ). The lower surface  121  of the locking sleeve  120  is configured with a profile that includes features configured to interact with the head  132  of the pin member  130  in such a manner as to preclude rotation of the locking sleeve  120  about the gate  110  in the absence of an applied external force. For example, the lower surface  121  of the locking sleeve  120  includes a first notch  122  (e.g., an indentation) shown in  FIG. 1A . When the locking sleeve  120  is in the retainable unlocked position shown in  FIGS. 1A through 1C , the head  132  of the pin member  130  is disposed within the first notch  122 . As the spring member  138  forces the lower surface  121  within the notch  122  of the locking sleeve  120  against the head  132  of the pin member  130 , the notch  122  prevents the locking sleeve  120  from rotating in the counter-clockwise direction responsive to the rotational forces applied to the locking sleeve  120  by the spring member  138 . If, however, the locking sleeve  120  is moved relative to the gate  110  such that the head  132  of the pin member  130  is not disposed within the first notch  122 , the spring member  138  may urge the locking sleeve  120  to rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member  130  impinges on another feature of the lower surface  121  of the locking sleeve  120  (e.g., a second notch  124  shown in  FIG. 3A ) that precludes further rotation of the locking sleeve  120  in the counter-clockwise direction. 
         [0043]    Referring to  FIG. 1B , an aperture  128  is provided in the end of the locking sleeve  120  proximate the second end  106  of the body  102  (the upper end in the perspectives of  FIGS. 1A through 1C ). The aperture  128  is configured to allow the nose  108  at the second end  106  of the body  102  to pass therethrough when the aperture  128  is aligned with the nose  108  as shown in  FIG. 1B . The aperture  128  is aligned with the nose  108  when the locking sleeve  120  is in the retainable unlocked position shown in  FIGS. 1A through 1C . Thus, when the locking sleeve  120  is in the retainable unlocked position shown in  FIGS. 1A through 1C , a user of the carabiner  100  can pull the locking sleeve  120  and the gate  110  into an interior area enclosed by the body  102  of the carabiner  100 . In other words, a user can move the gate  110  into an open position shown in  FIGS. 2A through 2C  when the locking sleeve  120  is in the retainable unlocked position shown in  FIGS. 1A through 1C . 
         [0044]    Referring to  FIGS. 2A through 2C , as long as the locking sleeve  120  is not moved out of the retainable unlocked position shown in  FIGS. 1A through 1C  relative to the gate  110  (i.e., as long as the head  132  of the pin member  130  remains disposed within the first notch  122  in the surface  121  of the locking sleeve  120 ), the gate  110  can be freely moved back and forth between the closed position shown in  FIGS. 1A through 1C  and the open position shown in  FIGS. 2A through 2C . 
         [0045]    In some embodiments, the carabiner  100  may be configured such that, as the gate  110  is moved into the open position shown in  FIGS. 2A through 2C , the head  132  of the pin member  130  may be urged out from the notch  122  in the surface  121  of the locking sleeve  120  if the gate  110  (and locking sleeve  120 ) is pivoted to or beyond a threshold angle relative to the body  102  of the carabiner  100 . By way of example and not limitation, the locking sleeve  120  and the first end  104  of the body  102  may be sized and configured such that, as the gate  110  (and locking sleeve  120 ) is pivoted to a threshold angle relative to the body  102  of the carabiner  100 , as shown in  FIG. 2A , the lower surface  121  of the locking sleeve  120  will abut against the body  102  proximate the first end  104  thereof at a pinch point  140 . If the gate  110  (and locking sleeve  120 ) is further pivoted inward beyond the threshold angle relative to the body  102 , the contact between the body  102  and the locking sleeve  120  at the pinch point  140  will cause the locking sleeve  120  to slide longitudinally along the gate  110  away from the pin member  130  such that the head  132  of the pin member  130  is urged out from the first notch  122  in the lower surface  121  of the locking sleeve  120 . After the head  132  of the pin member  130  is urged out from the first notch  122  in the lower surface  121  of the locking sleeve  120 , the spring member  138  ( FIG. 4 ) between the gate  110  and the locking sleeve  120  will prevent the head  132  of the pin member  130  from returning to the notch  122  in the absence of an applied external force, and will urge the locking sleeve  120  to rotate to the locked position shown in  FIGS. 3A through 3C . 
         [0046]    As shown in  FIG. 2C , however, when the gate  110  (and the locking sleeve  120 ) is in the open position shown in  FIGS. 2A through 2C , a projection  126  ( FIG. 1C ) of the locking sleeve  120  that extends downward (from the perspective of  FIG. 2C ) past the pin member  130  and laterally beside the first end  104  of the body  102  prevents the locking sleeve  120  from rotating about the gate  110  responsive to the forces applied by the spring member  138  ( FIG. 4 ) until the gate  110  (and the locking sleeve  120 ) has pivoted back toward the closed position to an extent that the nose  108  of the second end  106  of the body  102  has passed at least partially through the aperture  128  in the end of the locking sleeve  120  proximate the second end  106  of the body  102 . Stated another way, the projection  126  may be sized and configured to pass over the body  102  only after the gate  110  (and the locking sleeve  120 ) has pivoted back toward the closed position and the nose  108  has passed at least partially through the aperture  128 . Thus, the projection  126  maintains the aperture  128  in the locking sleeve  120  in alignment with the nose  108  until the nose  108  has passed at least partially through the aperture  128 . If the aperture  128  were not maintained in alignment with the nose  108  until the nose  128  had passed at least partially through the aperture  128 , the spring member  138  could cause the locking sleeve  120  to rotate relative to the gate  110  such that the aperture  128  were not aligned with the nose  108 , in which case interference between the nose  108  and the end of the locking sleeve  120  proximate the second end  106  of the body  102  would prevent the gate  110  (and the locking sleeve  120 ) from returning to the closed position. 
         [0047]    As the projection  126  clears the body  102 , the nose  108  will be partially disposed within the aperture  128 . Interference between the nose  108  and the surfaces of the locking sleeve  120  within the aperture  128 , however, will prevent the locking sleeve  120  from further rotation about the gate  110  response to the forces acting on the locking sleeve  120  until the nose  108  has passed entirely through the aperture  128  in the locking sleeve  120 . 
         [0048]    As the gate  110  moves from the open position shown in  FIGS. 2A through 2C  into the closed position shown in  FIGS. 3A through 3C , the nose  108  of the second end  106  of the body  102  will pass entirely through the aperture  128  in the locking sleeve  120 , at which point, the spring member  138  ( FIG. 4 ) between the gate  110  and the locking sleeve  120  will cause the locking sleeve  120  to further rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member  130  is forced into a second notch  124  in the lower surface  121  of the locking sleeve  120 . The second notch  124  may be disposed adjacent the projection  126  such that the projection  126  prevents further rotation of the locking sleeve  120  about the gate  110  in the counter-clockwise direction. When the head  132  of the pin member  130  is disposed within the second notch  124 , the locking sleeve  120  is in a locked position in which the aperture  128  is not aligned with the nose  108  and the end of the locking sleeve  120  proximate the second end  106  of the body  102  locks the gate  110  to the nose  108  in the closed position. Thus, when the gate  110  is closed and the locking sleeve  120  is in the locked position, as shown in  FIGS. 3A through 3C , the locking sleeve  120  prevents the gate  110  from inadvertently being opened. 
         [0049]    To unlock the locking sleeve  120  and open the gate  110 , a user may apply a force to the locking sleeve  120  to move the locking sleeve  120  out of the locked position shown in  FIGS. 3A through 3C  and to rotate the locking sleeve  120  about the gate  110  until the aperture  128  in the locking sleeve  120  is aligned with the nose  108 , at which point the gate  110  may be opened. In particular, a user may apply a force to the locking sleeve  120  to cause the locking sleeve  120  to slide longitudinally along the gate  110  toward the second end  106  of the body  102 , and to cause the locking sleeve  120  to rotate in the clockwise direction about the gate  110  in such a manner as to cause the head  132  of the pin member  130  to be dislodged out of the second notch  124 , to align the aperture  128  with the nose  108 , and to open the gate  110 . 
         [0050]    Optionally, a user may move the locking sleeve  120  from the locked position shown in  FIGS. 3A through 3C  to the retainable unlocked position shown in  FIGS. 1A through 1C , in which the head  132  of the pin member  130  is lodged within the first notch  122  in the locking sleeve  120 . If the user lodges the head  132  of the pin member  130  within the first notch  122  in the locking sleeve  120  before or after moving the gate  110  to the open position, the locking sleeve  120  may be freely opened and closed, as previously described herein, without causing the locking sleeve  120  to move into the locked position (shown in  FIGS. 3A through 3C ) until the locking sleeve  120  is pivoted relative to the body  102  beyond the threshold angle. If, however, the user does not lodge the head  132  of the pin member  130  within the first notch  122  in the locking sleeve  120  before or after moving the gate  110  to the open position, the locking sleeve  120  will return to the locked position shown in  FIGS. 3A through 3C  when the gate  110  returns to the closed position after the user opens the gate  110 . 
         [0051]      FIGS. 5A through 5C  illustrate another embodiment of a carabiner  200  of the present invention. The carabiner  200  is generally similar to the carabiner  100  previously described herein, and has a generally C-shaped body  102  and a gate  110  substantially similar to those of the carabiner  100 . The carabiner  200  also includes a locking sleeve  220  that is movable between a locked position and a retainable unlocked position. In the carabiner  200 , however, the locking sleeve  220  is biased toward the second end  106  of the body  102 , instead of toward the first end  104  of the body  102 , as is the locking sleeve  220  of the carabiner  100 .  FIG. 5A  illustrates the carabiner  200  with the gate  110  in the closed position and the locking sleeve  220  retained in a retainable unlocked position.  FIG. 5B  illustrates the carabiner  200  with the gate  110  in an open position and the locking sleeve  220  in the process of being urged out from the retainable unlocked position.  FIG. 5C  illustrates the carabiner  200  with the gate  110  in the closed position and the locking sleeve  220  in the locked position. 
         [0052]    Referring to  FIG. 5A , the lower end of the gate  110  may be pivotally attached to the first end  104  of the body  102  using, for example, a pin member (e.g., a rivet) (like the pin member  130  of  FIGS. 1A through 1C ) that extends through the first end  104  of the body  102  and through the lower end of the gate  110 . As shown in  FIG. 5A , the pin member may include a head  132  that projects laterally outward from the first end  104  of the body  102  on one side thereof (e.g., the side shown in  FIG. 5A ). The pin member may be substantially flush with the surface of the first end  104  of the body  102  on an opposite side of the body  102 . The head  132  of the pin member may interact with features of the locking sleeve  220 , as discussed in further detail herein below. 
         [0053]    The second end  106  of the body  102  may include a nose  108  that is configured to be received within a receptacle (not visible in  FIGS. 5A through 5C ) (like the receptacle  112  shown in  FIG. 4 ) formed in the upper end of the gate  110  when the gate  110  is in the closed position. An aperture  228  is formed in the upper end of the locking sleeve  220  to allow the nose  108  to be received into the receptacle of the gate  110  as the gate  110  moves from the open position into the closed position, but the upper end of the gate  110  is configured to preclude the nose  108  from passing through the upper end of the gate  110 . 
         [0054]    The locking sleeve  220  is carried by, and positioned concentrically about, the gate  110 . The locking sleeve  220  and the gate  110  are configured such that the locking sleeve  220  can rotate circumferentially about the gate  110 , and such that the locking sleeve  220  can slide longitudinally along the gate  110 . 
         [0055]    A spring member (like the spring member  138  of  FIG. 4 ) is disposed between the gate  110  and the locking sleeve  220 . The spring member is hidden from view in  FIGS. 5A through 5C . The spring member may comprise a torsion spring that acts on both the gate  110  and the locking sleeve  220  in such a manner as to bias the locking sleeve  220  toward the second end  106  of the body  102  (the upward direction in the perspectives of  FIGS. 5A through 5C ), and also to rotationally bias the locking sleeve  220  in a counter-clockwise rotational direction about the gate  110  (when looking at the end surfaces of the gate  110  and locking sleeve  220  proximate the second end  106  of the body  102 ). 
         [0056]    With continued reference to  FIG. 5A , an elongated aperture  221  (e.g., a slot) is formed through the end of the locking sleeve  220  proximate the first end  104  of the body  102 , and the locking sleeve  220  is assembled with the gate  110  and the pin member such that the head  132  of the pin member is disposed within the elongated aperture  221 . Thus, in the absence of an applied external force, the spring member forces the locking sleeve  220  toward the second end  106  of the body  102  (in the upward direction in the perspectives of  FIGS. 5A through 5C ) to cause a lower surface  227  of the locking sleeve  220  within the elongated aperture  221  to abut against the head  132  of the pin member, which prevents the locking sleeve  220  from further movement toward the second end  104  of the body  102 . A user, however, can apply an external force to the locking sleeve  220  to cause the locking sleeve  220  to slide toward the first end  104  of the body  102  (in the downward direction in the perspectives of  FIGS. 5A through 5C ). 
         [0057]    Also, in the absence of an applied external force, the spring member forces the locking sleeve  220  to rotate in the counter-clockwise direction (when looking at the end surfaces of the gate  110  and locking sleeve  220  proximate the second end  106  of the body  102 ). The lower surface  227  of the locking sleeve  220  is configured with a profile that includes features configured to interact with the head  132  of the pin member in such a manner as to preclude rotation of the locking sleeve  220  about the gate  110  in the absence of an applied external force. For example, the lower surface  227  of the locking sleeve  220  within the elongated aperture  221  includes a first notch  222  (e.g., an indentation) shown in  FIGS. 5A and 5B . When the locking sleeve  220  is in the retainable unlocked position shown in  FIG. 5A , the head  132  of the pin member is disposed within the first notch  222 . As the spring member forces the lower surface  227  of the locking sleeve  220  within the notch  222  against the head  132  of the pin member, the notch  222  prevents the locking sleeve  220  from rotating in the counter-clockwise direction responsive to the rotational forces applied to the locking sleeve  220  by the spring member. If, however, the locking sleeve  220  is moved relative to the gate  110  such that the head  132  of the pin member is not disposed within the first notch  222 , the spring member may urge the locking sleeve  220  to rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member impinges on another feature of the lower surface  227  of the locking sleeve  220  within the elongated aperture  221  (e.g., a second notch  224  shown in  FIGS. 5A through 5C ) that precludes further rotation of the locking sleeve  220  in the counter-clockwise direction. 
         [0058]    Referring to  FIG. 5B , an aperture  228  is provided in the end of the locking sleeve  220  proximate the second end  106  of the body  102  (the upper end in the perspectives of  FIGS. 5A through 5C ). The aperture  228  is configured to allow the nose  108  at the second end  106  of the body  102  to pass therethrough when the aperture  228  is aligned with the nose  108 , as shown in  FIG. 5A . The aperture  228  is aligned with the nose  108  when the locking sleeve  220  is in the retainable unlocked position shown in  FIG. 5A . Thus, when the locking sleeve  220  is in the retainable unlocked position shown in  FIG. 5A , a user of the carabiner  200  can pull the locking sleeve  220  and the gate  110  into an interior area enclosed by the body  102  of the carabiner  200 . In other words, a user can move the gate  110  into the open position shown in  FIG. 5B  when the locking sleeve  220  is in the retainable unlocked position shown in  FIG. 5A . 
         [0059]    Referring to  FIG. 5B , as long as the locking sleeve  220  is not moved out of the retainable unlocked position shown in  FIG. 5A  relative to the gate  110  (i.e., as long as the head  132  of the pin member  130  remains disposed within the first notch  222  within the aperture  221  of the locking sleeve  220 ), the gate  110  can be freely moved back and forth between the closed position shown in  FIG. 5A  and an open position as shown in  FIG. 5B . 
         [0060]    In some embodiments, the carabiner  200  may be configured such that, as the gate  110  is moved into the open position shown in  FIG. 5B , the head  132  of the pin member may be urged out from the notch  222  in the lower surface  227  of the locking sleeve  220  within the elongated aperture  221  if the gate  110  (and the locking sleeve  220 ) is pivoted to or beyond a threshold angle relative to the body  102  of the carabiner  200 . By way of example and not limitation, the locking sleeve  220  and the body  102  may be sized and configured such that, as the gate  110  and locking sleeve  220  are pivoted to a threshold angle relative to the body  102  of the carabiner  200 , as shown in  FIG. 5B , an upper surface  250  of the locking sleeve  220  will abut against the body  102  proximate at a pinch point  240 . If the gate  110  and the locking sleeve  220  are further pivoted inward beyond the threshold angle relative to the body  102 , the contact between the body  102  and the locking sleeve  220  at the pinch point  240  will cause the locking sleeve  220  to slide longitudinally along the gate  110  toward the first end  104  of the body  102  and the pin member such that the head  132  of the pin member is urged out from the first notch  222  within the elongated aperture  221  of the locking sleeve  220 . After the head  132  of the pin member is urged out from the first notch  222  within the elongated aperture  221  of the locking sleeve  220 , the spring member between the gate  110  and the locking sleeve  220  will prevent the head  132  of the pin member from returning to the notch  222  in the absence of an applied external force, and will urge the locking sleeve  220  to rotate to the locked position shown in  FIG. 5C . 
         [0061]    When the gate  110  (and the locking sleeve  220 ) is in the open position shown in  FIG. 5B , a projection  226  of the locking sleeve  220  that extends downward (from the perspective of  FIG. 5B ) past the pin member  130  and laterally beside the first end  104  of the body  102 , prevents the locking sleeve  220  from rotating about the gate  110  responsive to the forces applied by the spring member until the gate  110  (and the locking sleeve  220 ) has pivoted back toward the closed position to an extent that the nose  108  of the second end  106  of the body  102  has passed at least partially through the aperture  228  in the end of the locking sleeve  220  proximate the second end  106  of the body  102 . Stated another way, the projection  226  may be sized and configured to pass over the body  102  only after the gate  110  (and the locking sleeve  220 ) has pivoted back toward the closed position and the nose  108  has passed at least partially through the aperture  228  in the locking sleeve  220 . Thus, the projection  226  maintains the aperture  228  in the locking sleeve  220  in alignment with the nose  108  until the nose  108  has passed at least partially through the aperture  228 . If the aperture  228  were not maintained in alignment with the nose  108  until the nose  108  had passed at least partially through the aperture  228 , the spring member could cause the locking sleeve  220  to rotate relative to the gate  110  such that the aperture  228  were not aligned with the nose  108 , in which case interference between the nose  108  and the end of the locking sleeve  220  proximate the second end  106  of the body  102  would prevent the gate  110  (and the locking sleeve  220 ) from returning to the closed position. 
         [0062]    As the projection  226  clears the body  102 , the nose  108  will be partially disposed within the aperture  228 . Interference between the nose  108  and the surfaces of the locking sleeve  220  within the aperture  228 , however, will prevent the locking sleeve  220  from further rotation about the gate  110  response to the forces acting on the locking sleeve  220  until the nose  108  has passed entirely through the aperture  228  in the locking sleeve  220  and into the receptacle in the gate  110 . 
         [0063]    As the gate  110  moves from the open position shown in  FIG. 5B  into the closed position shown in  FIG. 5C , the nose  108  of the second end  106  of the body  102  will pass entirely through the aperture  228  in the locking sleeve  220 , at which point, the spring member between the gate  110  and the locking sleeve  220  will cause the locking sleeve  220  to further rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member is forced into a second notch  224  in the lower surface  227  of the locking sleeve  220  within the elongated aperture  221 . The end of the elongated aperture  221  adjacent the second notch  224  prevents further rotation of the locking sleeve  220  about the gate  110  in the counter-clockwise direction. When the head  132  of the pin member is disposed within the second notch  224 , the locking sleeve  220  is in a locked position in which the aperture  228  is not aligned with the nose  108  and the end of the locking sleeve  220  proximate the second end  106  of the body  102  locks the gate  110  to the nose  108  in the closed position. Thus, when the gate  110  is closed and the locking sleeve  220  is in the locked position, as shown in  FIG. 5C , the locking sleeve  220  prevents the gate  110  from inadvertently being opened. 
         [0064]    To unlock the locking sleeve  220  and open the gate  110 , a user may apply a force to the locking sleeve  220  to move the locking sleeve  220  out of the locked position shown in  FIG. 5C  and to rotate the locking sleeve  220  about the gate  110  until the aperture  228  in the locking sleeve  220  is aligned with the nose  108 , at which point the gate  110  may be opened. In particular, a user may apply a force to the locking sleeve  220  to cause the locking sleeve  220  to slide longitudinally along the gate  110  toward the first end  104  of the body  102 , and to cause the locking sleeve  220  to rotate in the clockwise direction about the gate  110  in such a manner as to cause the head  132  of the pin member to be dislodged out of the second notch  224 , to align the aperture  228  with the nose  108 , and to open the gate  110 . 
         [0065]    Optionally, a user may move the locking sleeve  220  from the locked position shown in  FIG. 5C  to the retainable unlocked position shown in  FIG. 5A , in which the head  132  of the pin member is lodged within the first notch  222  in the locking sleeve  220 . If the user lodges the head  132  of the pin member within the first notch  222  in the locking sleeve  220  before or after moving the gate  110  to the open position, the locking sleeve  220  may be freely opened and closed, as previously described herein, without causing the locking sleeve  220  to move into the locked position (shown in  FIG. 5C ) until the locking sleeve  220  is pivoted relative to the body  102  beyond the threshold angle. If, however, the user does not lodge the head  132  of the pin member within the first notch  222  in the locking sleeve  220  before or after moving the gate  110  to the open position, the locking sleeve  220  will return to the locked position shown in  FIG. 5C  when the gate  110  returns to the closed position after the user opens the gate  110 . 
         [0066]      FIGS. 6A through 6C  illustrate another embodiment of a carabiner  300  of the present invention. The carabiner  300  is generally similar to the carabiner  100  previously described with reference to  FIGS. 1A-1C , and has a generally C-shaped body  102  and a gate  110  like those of the carabiner  100 . The carabiner  300  also includes a locking sleeve  320  that is movable between a locked position and a retainable unlocked position. Like the locking sleeve  120  of the carabiner  100 , the locking sleeve  320  of the carabiner  300  is biased toward the first end  104  of the body  102 .  FIG. 6A  illustrates the carabiner  300  with the gate  110  in the closed position and the locking sleeve  320  retained in a retainable unlocked position.  FIG. 6B  illustrates the carabiner  300  with the gate  110  in an open position and the locking sleeve  320  in the process of being urged out from the retainable unlocked position.  FIG. 6C  illustrates the carabiner  300  with the gate  110  in the closed position and the locking sleeve  320  in the locked position. 
         [0067]    Referring to  FIG. 6A , the lower end of the gate  110  may be pivotally attached to the first end  104  of the body  102  using, for example, a pin member (e.g., a rivet) (like the pin member  130  of  FIGS. 1A through 1C ) that extends through the first end  104  of the body  102  and through the lower end of the gate  110 . The pin member may include a head  132  that projects laterally outward from the first end  104  of the body  102  on one side thereof (e.g., the side shown in  FIG. 6A ). The head  132  of the pin member may interact with features of the locking sleeve  320 , as discussed in further detail herein below. 
         [0068]    The second end  106  of the body  102  may include a nose  108  that is configured to be received within a receptacle (not visible in  FIGS. 6A through 6C ) (like the receptacle  112  shown in  FIG. 4 ) formed in the upper end of the gate  110  when the gate  110  is in the closed position. An aperture  328  is formed in the upper end of the locking sleeve  320  to allow the nose  108  to be received into the receptacle of the gate  110  as the gate  110  moves from the open position into the closed position, but the upper end of the gate  110  may by configured to preclude the nose  108  from passing entirely through the upper end of the gate  110 . 
         [0069]    The locking sleeve  320  is carried by, and positioned concentrically about, the gate  110 . The locking sleeve  320  and the gate  110  are configured such that the locking sleeve  320  can rotate circumferentially about the gate  110 , and such that the locking sleeve  320  can slide longitudinally along the gate  110 . 
         [0070]    A spring member (like the spring member  138  of  FIG. 4 ) is disposed between the gate  110  and the locking sleeve  320 . The spring member is hidden from view in  FIGS. 6A through 6C . The spring member may comprise a torsion spring that acts on both the gate  110  and the locking sleeve  320  in a similar manner as does the spring member  138  of carabiner  100 , so as to bias the locking sleeve  320  toward the first end  104  of the body  102  (the downward direction from the perspectives of  FIGS. 6A through 6C ), and also to rotationally bias the locking sleeve  320  in a counter-clockwise rotational direction about the gate  110  (when looking at the end surfaces of the gate  110  and locking sleeve  320  proximate the second end  106  of the body  102 ). 
         [0071]    With continued reference to  FIG. 6A , an elongated aperture  321  (e.g., a slot) is formed through the locking sleeve  320  near the end thereof proximate the first end  104  of the body  102 , and the locking sleeve  320  is assembled with the gate  110  and the pin member such that the head  132  of the pin member is disposed within the elongated aperture  321 . Thus, in the absence of an applied external force, the spring member forces the locking sleeve  320  toward the first end  104  of the body  102  (in the downward direction in the perspectives of  FIGS. 6A through 6C ) to cause an upper surface  327  of the locking sleeve  320  within the elongated aperture  321  to abut against the head  132  of the pin member, which prevents the locking sleeve  320  from further movement toward the second end  104  of the body  102 . A user, however, can apply an external force to the locking sleeve  320  to cause the locking sleeve  320  to slide toward the second end  106  of the body  102  (in the upward direction in the perspectives of  FIGS. 6A through 6C ). 
         [0072]    Also, in the absence of an applied external force, the spring member forces the locking sleeve  320  to rotate in the counter-clockwise direction (when looking at the end surfaces of the gate  110  and locking sleeve  320  proximate the second end  106  of the body  102 ). The upper surface  327  of the locking sleeve  320  is configured with a profile that includes features configured to interact with the head  132  of the pin member in such a manner as to preclude rotation of the locking sleeve  320  about the gate  110  in the absence of an applied external force. For example, the upper surface  327  of the locking sleeve  320  within the elongated aperture  321  includes a first notch  322  (e.g., an indentation) shown in  FIGS. 6A and 6B . When the locking sleeve  320  is in the retainable unlocked position shown in  FIG. 5A , the head  132  of the pin member is disposed within the first notch  322 . As the spring member forces the upper surface  327  of the locking sleeve  320  within the notch  322  against the head  132  of the pin member, the notch  322  prevents the locking sleeve  320  from rotating in the counter-clockwise direction responsive to the rotational forces applied to the locking sleeve  320  by the spring member. If, however, the locking sleeve  320  is moved relative to the gate  110  such that the head  132  of the pin member is not disposed within the first notch  322 , the spring member may urge the locking sleeve  320  to rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member impinges on another feature of the upper surface  327  of the locking sleeve  320  within the elongated aperture  321  (e.g., a second notch  324  shown in  FIGS. 6A and 6C ) that precludes further rotation of the locking sleeve  320  in the counter-clockwise direction. 
         [0073]    Referring to  FIG. 6B , an aperture  328  is provided in the end of the locking sleeve  320  proximate the second end  106  of the body  102  (the upper end in the perspectives of  FIGS. 6A through 6C ). The aperture  328  is configured to allow the nose  108  at the second end  106  of the body  102  to pass therethrough when the aperture  328  is aligned with the nose  108 , as shown in  FIG. 6A . The aperture  328  is aligned with the nose  108  when the locking sleeve  320  is in the retainable unlocked position shown in  FIG. 6A . Thus, when the locking sleeve  320  is in the retainable unlocked position shown in  FIG. 6A , a user of the carabiner  300  can move the gate  110  into the open position shown in  FIG. 6B . 
         [0074]    Referring to  FIG. 6B , as long as the locking sleeve  320  is not moved out of the retainable unlocked position shown in  FIG. 6A  relative to the gate  110  (i.e., as long as the head  132  of the pin member  130  remains disposed within the first notch  322  within the aperture  321  of the locking sleeve  320 ), the gate  110  can be freely moved back and forth between the closed position shown in  FIG. 6A  and an open position as shown in  FIG. 6B . 
         [0075]    In some embodiments, the carabiner  300  may be configured such that, as the gate  110  is moved into the open position shown in  FIG. 6B , the head  132  of the pin member may be urged out from the notch  322  in the upper surface  327  of the locking sleeve  320  within the elongated aperture  321  if the gate  110  (and the locking sleeve  320 ) is pivoted to or beyond a threshold angle relative to the body  102  of the carabiner  300 . By way of example and not limitation, the locking sleeve  320  and the first end  104  of the body  102  may be sized and configured such that, as the gate  110  (and locking sleeve  320 ) is pivoted to a threshold angle relative to the body  102  of the carabiner  300 , as shown in  FIG. 6B , a lower surface of the locking sleeve  320  will abut against the body  102  proximate the first end  104  thereof at a pinch point  340 . If the gate  110  (and locking sleeve  320 ) is further pivoted inward beyond the threshold angle relative to the body  102 , the contact between the body  102  and the locking sleeve  320  at the pinch point  340  will cause the locking sleeve  320  to slide longitudinally along the gate  110  toward the second end  106  of the body  102  and away from the pin member such that the head  132  of the pin member is urged out from the first notch  322  within the elongated aperture  321  of the locking sleeve  320 . After the head  132  of the pin member is urged out from the first notch  322  within the elongated aperture  321  of the locking sleeve  320 , the spring member between the gate  110  and the locking sleeve  320  will prevent the head  132  of the pin member from returning to the notch  322  in the absence of an applied external force, and will urge the locking sleeve  320  to rotate to the locked position shown in  FIG. 6C . 
         [0076]    When the gate  110  (and the locking sleeve  320 ) is in the open position shown in  FIG. 6B , a projection  326  of the locking sleeve  320  that extends downward (from the perspective of  FIG. 6B ) past the pin member and laterally beside the first end  104  of the body  102 , prevents the locking sleeve  320  from rotating about the gate  110  responsive to the forces applied by the spring member until the gate  110  (and the locking sleeve  320 ) has pivoted back toward the closed position to an extent that the nose  108  of the second end  106  of the body  102  has passed at least partially through the aperture  328  in the end of the locking sleeve  320  proximate the second end  106  of the body  102 . Stated another way, the projection  326  may be sized and configured to pass over the body  102  only after the gate  110  (and the locking sleeve  320 ) has pivoted back toward the closed position and the nose  108  has passed at least partially through the aperture  328  in the locking sleeve  320 . Thus, the projection  326  maintains the aperture  328  in the locking sleeve  320  in alignment with the nose  108  until the nose  108  has passed at least partially through the aperture  328 . If the aperture  328  were not maintained in alignment with the nose  108  until the nose  108  had passed at least partially through the aperture  328 , the spring member could cause the locking sleeve  320  to rotate relative to the gate  110  such that the aperture  328  were not aligned with the nose  108 , in which case interference between the nose  108  and the end of the locking sleeve  320  proximate the second end  106  of the body  102  would prevent the gate  110  (and the locking sleeve  320 ) from returning to the closed position. 
         [0077]    As the projection  326  clears the body  102 , the nose  108  will be partially disposed within the aperture  328 . Interference between the nose  108  and the surfaces of the locking sleeve  320  within the aperture  328 , however, will prevent the locking sleeve  320  from further rotation about the gate  110  response to the forces acting on the locking sleeve  320  until the nose  108  has passed entirely through the aperture  328  in the locking sleeve  320  and into the receptacle in the gate  110 . 
         [0078]    As the gate  110  moves from the open position shown in  FIG. 6B  into the closed position shown in  FIG. 6C , the nose  108  of the second end  106  of the body  102  will pass entirely through the aperture  328  in the locking sleeve  320 , at which point, the spring member between the gate  110  and the locking sleeve  320  will cause the locking sleeve  320  to further rotate in the counter-clockwise direction about the gate  110  until the head  132  of the pin member is forced into a second notch  324  in the upper surface  327  of the locking sleeve  320  within the elongated aperture  321 . The end of the elongated aperture  321  adjacent the second notch  324  prevents further rotation of the locking sleeve  320  about the gate  110  in the counter-clockwise direction. When the head  132  of the pin member is disposed within the second notch  324 , the locking sleeve  320  is in a locked position in which the aperture  328  is not aligned with the nose  108  and the end of the locking sleeve  320  proximate the second end  106  of the body  102  locks the gate  110  to the nose  108  in the closed position. Thus, when the gate  110  is closed and the locking sleeve  320  is in the locked position, as shown in  FIG. 6C , the locking sleeve  320  prevents the gate  110  from inadvertently being opened. 
         [0079]    To unlock the locking sleeve  320  and open the gate  110 , a user may apply a force to the locking sleeve  320  to move the locking sleeve  320  out of the locked position shown in  FIG. 6C  and to rotate the locking sleeve  320  about the gate  110  until the aperture  328  in the locking sleeve  320  is aligned with the nose  108 , at which point the gate  110  may be opened. In particular, a user may apply a force to the locking sleeve  320  to cause the locking sleeve  320  to slide longitudinally along the gate  110  toward the second end  106  of the body  102 , and to cause the locking sleeve  320  to rotate in the clockwise direction about the gate  110  in such a manner as to cause the head  132  of the pin member to be dislodged out of the second notch  324 , to align the aperture  328  with the nose  108 , and to open the gate  110 . 
         [0080]    Optionally, a user may move the locking sleeve  320  from the locked position shown in  FIG. 6C  to the retainable unlocked position shown in  FIG. 6A , in which the head  132  of the pin member is lodged within the first notch  322  in the locking sleeve  320 . If the user lodges the head  132  of the pin member within the first notch  322  in the locking sleeve  320  before or after moving the gate  110  to the open position, the locking sleeve  320  may be freely opened and closed, as previously described herein, without causing the locking sleeve  320  to move into the locked position (shown in  FIG. 6C ) until the locking sleeve  320  is pivoted relative to the body  102  beyond the threshold angle. If, however, the user does not lodge the head  132  of the pin member within the first notch  322  in the locking sleeve  320  before or after moving the gate  110  to the open position, the locking sleeve  320  will return to the locked position shown in  FIG. 6C  when the gate  110  returns to the closed position after the user opens the gate  110 . 
         [0081]    Thus described, embodiments of carabiners of the present invention may be said to be operable in each of a “manual” mode and an “automatic” mode. For example, when the locking sleeve  120 ,  220 ,  320  of the carabiner  100 ,  200 ,  300  is in the retainable unlocked position relative to the gate  110  (i.e., when the head  132  of the pin member  130  is disposed within the first notch  122 ,  222 ,  322  of the locking sleeve  120 ,  220 ,  320 ), the carabiner  100 ,  200 ,  300  may be said to be operable in a manual mode in which the gate  110  may be manually moved back and forth between the open and closed position, so long as the gate  110  is not pivoted beyond the threshold angle relative to the body  102  of the carabiner  100 ,  200 ,  300 , and the head  132  of the pin member  130  is not dislodged from the first notch  122 ,  222 ,  322 . To operate the carabiner  100 ,  200 ,  300  in the automatic mode, the gate  110  may be opened and pivoted relative to the body  102  of the carabiner  100 ,  200 ,  300  beyond the threshold angle to urge the head  132  of the pin member  130  out of the first notch  122 ,  222 ,  322 , or the locking sleeve  120 ,  220 ,  320  may simply be moved by a user from the retainable unlocked position to the locked position without opening the gate  110 . As a result, the locking sleeve  120 ,  220 ,  320  will automatically move to the locked position the next time the gate  110  returns to the closed position. 
         [0082]    Although the foregoing description contains many specifics, these are not to be construed as limiting the scope of the present invention, but merely as providing examples of certain embodiments of the invention. Additional embodiments of the invention may be devised which do not depart from the spirit or scope of the invention. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description of certain embodiments of the invention.