Patent Publication Number: US-9844857-B2

Title: Locking pliers with handle locking mechanism

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a Continuation-in-Part of parent U.S. application Ser. No. 13/360,506, filed on Jan. 27, 2012 entitled “Locking Pliers with Handle Locking Mechanism,” and claims the benefit of priority thereof. The aforementioned parent application is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The present patent application relates generally to pliers having an overcenter locking position. 
     BACKGROUND 
     Locking pliers generally rely on an “overcenter” linkage to lock the pliers into a position compressing jaws thereof against a work piece. It may be appreciated, however, that bumping or otherwise unintentionally disturbing such pliers in such an overcenter locked position may cause the pliers to spring open and disengage from the work piece. Among other things, the present application relates to preventing pliers from unintentionally moving from an overcenter locked position. 
     SUMMARY 
     According to one aspect of this present patent disclosure, a pair of pliers is provided. The pair of pliers includes an upper structure, a lower structure, an overcenter linkage, and a lock member. The upper structure includes an upper jaw and an upper handle extending from the upper jaw. The lower structure includes a lower jaw and a lower handle. The lower jaw is configured to pivot relative to the upper jaw. The lower handle is configured to pivot relative to the lower jaw. The overcenter linkage is operatively connected between the upper structure and the lower structure. The linkage biases the lower handle and the lower jaw away from the upper handle and the upper jaw, respectively, when in a jaw-opening position, and enables the lower jaw and the lower handle to be retained in a closed configuration when the linkage is in a jaw-closing position. The lock member is movable between a locking configuration and a release configuration. When the lock member is in the locking configuration, it prevents pivoting movement of the lower handle from the closed configuration and retains the jaws in a closed position. When the lock member is in the release configuration, it enables the lower handle to be moved away from the closed configuration and allows the jaws to move to an open position. Movement of the lock member from the locking configuration to the release configuration requires sequential movement of the lock member in a first direction and then in a second direction. The second direction is different than the first direction. 
     These and other objects, features, and characteristics of the present patent application, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one embodiment of the patent application, the structural components illustrated herein are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not a limitation of the patent application. In addition, it should be appreciated that structural features shown or described in any one embodiment herein can be used in other embodiments as well. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the patent application. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features of the pliers in accordance with one embodiment are shown in the drawings, in which like reference numerals designate like elements. The drawings form part of this original disclosure in which: 
         FIG. 1  is an exploded view of an embodiment of the locking pliers of the present patent application, showing the constituent components thereof; 
         FIG. 2  is a perspective view of the embodiment of  FIG. 1 , showing the locking pliers in an unlocked position, whereby the locking pliers may move into and out of an overcenter locked position; 
         FIG. 3  is another perspective view of the embodiment of  FIG. 1 , showing the locking pliers in a locked position, whereby the locking pliers are prevented from moving out of the overcenter locked position; 
         FIG. 4  is an exploded view of another embodiment of the locking pliers of the present patent application, showing the constituent components thereof; 
         FIG. 5  is a side view of the embodiment of  FIG. 4 , showing the locking pliers in an unlocked position, whereby the locking pliers may move into and out of an overcenter locked position; 
         FIG. 6  is another side view of the embodiment of  FIG. 4 , showing the locking pliers in a locked position, whereby the locking pliers are prevented from moving out of the overcenter locked position; 
         FIGS. 7 and 8  show a side elevational view and a perspective view of a locking pliers in a locked position, whereby the locking pliers are prevented from moving out of an overcenter locked position, in accordance with another embodiment of the present patent application; 
         FIG. 9  is another side elevational view of the locking pliers of  FIG. 7 , showing the locking pliers in an unlocked position, whereby the locking pliers may move into and out of the overcenter locked position; 
         FIGS. 10, 11 and 12  show partial, close-up detailed views of the locking pliers, where  FIG. 10  shows the locking pliers in the locked position, while  FIGS. 11 and 12  show the locking pliers in the unlocked position; 
         FIG. 12 a    shows a top elevational view of the locking pliers, where the locking pliers in the locked position and where some of the components or parts of the locking pliers are not shown for the sake of clarity; 
         FIG. 13  shows a front elevational view of an overcenter linkage of the locking pliers in accordance with an embodiment of the present patent application; 
         FIGS. 14 and 15  show a front elevational view and a close-up detailed view of a lower handle of the locking pliers in accordance with an embodiment of the present patent application; 
         FIGS. 16-18  show a perspective view, a front elevational view and a rear elevational view of a collar member of the locking pliers in accordance with an embodiment of the present patent application; 
         FIGS. 19 and 20  show an assembled view of a lock assembly of the locking pliers and a detailed view of the components of the lock assembly in accordance with an embodiment of the present patent application; 
         FIG. 21  shows a perspective view of a lock member of the lock assembly in accordance with an embodiment of the present patent application; 
         FIG. 22  shows a partially assembled view of the lock assembly in accordance with an embodiment of the present patent application; 
         FIGS. 23, 23A and 24  show a rear elevational view, a perspective view and a front elevational view of a manually engageable member of the lock assembly in accordance with an embodiment of the present patent application; 
         FIGS. 25, 25A and 26  show a rear perspective view, a front perspective view and a front elevational view of a manually engageable member of the lock assembly in accordance with another embodiment of the present patent application; and 
         FIGS. 27 and 28  show a rear perspective view and a front perspective view of a manually engageable member of the lock assembly in accordance with yet another embodiment of the present patent application. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  illustrates an exploded view of an embodiment of a pair of locking pliers  10  of the present patent application, wherein components thereof may be seen. The locking pliers  10  comprise an upper handle  20  that is elongated between a first end  30  and a second end  40 . Received in the first end  30  is an upper jaw  50  of the locking pliers  10 , forming an upper structure. As shown in the illustrated embodiment, the upper jaw  50  may be slidably received into the first end  30 , and may be secured thereto by any appropriate manner, including but not limited to being welded, glued, removably or non-removably attached by one or more mechanical fasteners, or so on. In some embodiments, the upper jaw  50  may be integrally formed at the first end  30  of the upper handle  20 . 
     Pivotally coupled to the handle  20  by a first pivot pin  60  is a lower jaw  70 . As shown in the illustrated embodiment, a first pivot hole  80  of the lower jaw  70  is configured to be received in the upper handle  20 , and align with corresponding upper handle pivot holes  90 . The upper handle pivot holes  90  extend through the upper handle  20  (or otherwise formed on opposing faces of the upper handle  20 ) and have a receiving space therebetween to receive a portion of the lower jaw  70 , such that the first pivot pin  60  passes through both the upper handle pivot holes  90  and the first pivot hole  80 , holding the lower jaw  70  within the space between the upper handle pivot holes  90  by the first pivot pin  60 . The lower jaw  70  is therefore able to pivot on the first pivot pin  60  relative to the upper handle  20  and the upper jaw  50 . In various embodiments, the first pivot pin  60  may be configured as a screw, a bolt, a rivet, or any other appropriate body configured to pivotally secure the lower jaw  70  to the upper handle  20 . It may be appreciated, then, that the lower jaw  70  may pivot with respect to the upper jaw  50 , to open and close the jaws of the locking pliers  10 . 
     Also pivotally coupled to the lower jaw  70  is a lower handle  100 , which is elongated, to extend generally parallel to but below the upper handle  20 . The lower jaw  70  and the lower handle  100  together form a lower structure. As shown, the lower handle  100  includes therein first lower handle pivot holes  110 , that extend through the lower handle  100 , and are configured to receive a portion of the lower jaw  70  therebetween. Specifically, the lower handle  100  is configured to receive a portion of the lower jaw  70  that contains a second pivot hole  120  formed therein. A second pivot pin  130  is received by both the first lower handle pivot holes  110  and the second pivot hole  120  of the lower jaw  70 , to pivotally couple the lower handle  100  and the lower jaw  70 . In various embodiments, the second pivot pin  130  may be configured as a screw, a bolt, a rivet, or any other appropriate body configured to pivotally secure the lower jaw  70  to the lower handle  100 . 
     An overcenter linkage  140  operatively connects between the upper structure and the lower structure. Specifically, the linkage includes a linkage bar  145 , which is configured to move into and out of an overcenter jaw-closing position, described in greater detail below. As shown, the linkage bar  145  contains therein an upper linkage pivot  150 , which is configured to be pivotally coupled to a receiving region in the upper handle  20 . While in some embodiments the upper linkage pivot  150  may engage an axle defining a pivot axis in the receiving region, in other embodiments the upper linkage pivot  150  may comprise a curved shape on the linkage bar  145 , where the curved shape generally surrounds a pivot axis. A lower linkage pivot hole  160  of the linkage bar  145  is configured to be received by the lower handle  100 . In the illustrated embodiment, the lower handle  100  includes second lower handle pivot holes  170 , surrounding a region in which the lower linkage pivot hole  160  is inserted into, so that the second lower handle pivot holes  170  are aligned with the lower linkage pivot hole  160 . As such, in some embodiments the lower handle  100  may have a generally U-shaped cross section. A third pivot pin  180  may therefore be inserted through both the second lower handle pivot holes  170  and the lower linkage pivot hole  160 , such that the linkage bar  145  couples the lower handle  100  to the upper handle  20 , and may push or pull on the assembly of the lower handle  100  and the lower jaw  70  to move the locking pliers  10  into and out of a relaxed jaw-opening position, a top-dead-center position, and the overcenter jaw-closing position, as described in greater detail below. 
     Further coupling the lower jaw  70  and the upper handle  20  as part of the linkage  140  may be a spring  190  having a first end  200  that is received in a receiving aperture  210  of the lower jaw  70 , and a second end  220  that is received in the upper handle. As discussed in greater detail below, the spring  190  is configured to pull the lower jaw  70  open, which would generally bias the linkage bar  145  into the relaxed jaw-opening position. When the linkage bar  145  moves into the jaw-closing position, however, the lower linkage pivot hole  160  is positioned to the interior of the second pivot hole  120  and the upper linkage pivot  150  (i.e. proximal to the upper handle  20 , resulting in any force applied between the upper jaw  50  and the lower jaw  70  act to drive the lower linkage pivot hole  160  further inward towards the upper handle  20 , instead of causing the lower jaw  70  to open from the upper jaw  50 , effectively locking the jaws around a work piece therebetween. As such, it may be appreciated that if the locking pliers  10  are bumped when in the overcenter jaw-closing position, the linkage may move from overcenter to top-dead-center (where the lower linkage pivot hole  160  is in alignment across the linkage bar  145  with the second pivot hole  120  and the upper linkage pivot  150 ), at which point the spring  190  may cause the linkage to spring into the relaxed jaw-opening position, opening the lower jaw  70  from the upper jaw  50 , and releasing the work piece. 
     It may be appreciated that the positioning of the linkage bar  145  may be modified by an adjustment knob  230 , which may be received in the handle  20 , and configured to modify the position of the upper linkage pivot  150  relative to the handle  20 . In the illustrated embodiment, the adjustment knob  230  is a turn-screw knob that extends from the second end  40  of the housing  20 , and may screw into and out of the housing  20  to move a pivot axis of the linkage bar  145  in the handle  20  either closer to or further from the upper jaw  50 . As such, the adjustment knob  230  may modify the angle of the linkage bar  145 , to allow the lower jaw  70  and the upper jaw  50  to clamp down onto different sizes of work pieces, and with different amounts of force. 
     The pivotal coupling of the upper handle  20 , lower jaw  70 , lower handle  100 , and linkage bar  145 , as well as the coupling of the spring  190  therebetween, may generally allow the locking pliers  10  to operate through the squeezing of the lower handle  100  towards the upper handle  20 . As the lower handle  100  is squeezed with a work piece between the upper jaw  50  and lower jaw  70 , the linkage bar  145  may pivot to the top-dead-center position. As the lower handle  100  is squeezed further, the linkage bar  145  may move to the overcenter jaw-closing position, causing the locking pliers  10  to remain clamped onto the work piece. To provide a mechanical advantage to move the linkage bar  145  back to the top-dead-center or the relaxed jaw-opening positions, and thus release the work piece, a release lever  240  is pivotally coupled to the lower handle  100 . As shown in  FIG. 1 , a release lever pivot pin  250  may be inserted through third lower handle pivot holes  260  formed in the lower handle  100 , and through a corresponding release lever pivot hole  270  formed in the release lever  240 . By lifting the release lever  240  towards the linkage bar  145 , a fulcrum point  280  formed in the release lever  240  may press against the linkage bar  145  with sufficient force to bring the linkage bar  145  back out of the overcenter jaw-closing position, and back into the top-dead-center or relaxed jaw-opening positions, releasing the lower jaw  70 . 
     As indicated above, it may be appreciated that the release spring  190  may be configured to promote the release of the lower jaw  70  and the linkage bar  145  from being locked in the overcenter jaw-closing position. As such, when the locking pliers  10  are locked around a work piece in the overcenter jaw-closing position, bumping or otherwise disturbing the locking pliers  10  may result in the linkage bar  145  slipping out of the overcenter jaw-closing position, leading to the lower jaw  70  opening away from the upper jaw  50 . In such a situation, any work piece located between the lower jaw  70  and the upper jaw  50  may be inadvertently released. Additionally, the force of the spring  190  may cause the locking pliers  10  to spring away from the work piece and subsequently fall from where the locking pliers  10  were positioned. Such unintentional unlocking of the locking pliers  10  may also occur where a user of the locking pliers  10  accidently pulls on the release lever  240 , moving the linkage bar  145  out of the overcenter locked position. As described in greater detail below, preventing such unintentional movements of the linkage bar  145  are an object of the present disclosure. 
     As shown in the exploded view of  FIG. 1 , a linkage latch  290  may be configured to lock the angle of the linkage bar  145  in place, so that the linkage bar  145  may not move out of the overcenter jaw-closing position, back into the top-dead-center or the relaxed jaw-opening positions. In the illustrated embodiment, the linkage latch  290  is configured to engage a latch receptacle  300  in the linkage bar  145 . Specifically in the illustrated embodiment, the linkage latch  290  is generally formed as a cylinder having both a smaller diameter region  310  and a larger diameter region  320 . The linkage latch  290  is configured to extend through a pair of latch holes  330  formed in the lower handle  100  that are positioned to be in alignment with the latch receptacle  300  when the linkage bar  145  is in the overcenter jaw-closing position. As shown in the illustrated embodiment, the latch receptacle  300  may be formed as having a cross-sectional shape of a generally enclosed circle extending through the linkage bar  145 , with a side opening  340  extending to one side of the linkage bar  145 . With such a configuration, the linkage latch  290  may slidably be positioned such that either the larger diameter region  320  or the smaller diameter region  310  is within the generally enclosed circular cross-sectional shape of the latch receptacle  300 . When the larger diameter region  320  is positioned in the latch receptacle  300 , the linkage bar  145  surrounds the larger diameter region  320 , which is unable to pass through the side opening  340 , preventing the linkage bar  145  from moving out of the overcenter locked position due to the engagement between the linkage latch  290  and the latch receptacle  300 . Alternatively, where the linkage latch  290  is positioned such that the smaller diameter region  310  is generally surrounded by the latch receptacle  300 , the linkage bar  145  may freely move from the overcenter jaw-closing position, as the smaller diameter region  310  may pass through the side opening  340  as the linkage bar  145  moves into and out of the overcenter jaw-closing position. Further shown in  FIG. 1  is a snap ring  350  that may be received on the linkage latch  290 , so as to provide a tactile sensation as the linkage latch  290  is moved between a locked position (where the larger diameter region  320  is positioned in the latch receptacle  300 ), and an unlocked position (where the smaller diameter region  310  is positioned in the latch receptacle  300 ). 
       FIGS. 2 and 3  depict perspective views of the locking pliers  10  as assembled. Specifically,  FIG. 2  illustrates the locking pliers  10  where the linkage latch  290  is in the unlocked position, such that the linkage bar  145  may freely move into and out of the overcenter position. Accordingly, the smaller diameter region  310  (obscured in  FIG. 2 ) is positioned to be in the plane of movement of the side opening  340  as the linkage bar  145  moves between the overcenter, top dead center, and relaxed jaw-opening positions. The larger diameter region  320  thus protrudes from the lower handle  100  when the locking pliers are not latched. As shown in  FIG. 3 , however, when the linkage latch  290  is in the locked position, the smaller diameter region  310  may extend from the lower handle  100 , while the larger diameter region  320  (obscured in  FIG. 3 ) positioned to be within the latch receptacle  300 , preventing the linkage bar  145  from moving out of the overcenter locked position by being too large to pass through the side opening  340  when the linkage bar  145  attempts to move, holding the linkage bar  145  in place. 
     It may be appreciated that other mechanisms for preventing movement of a linkage from the overcenter locked position are also possible, and may be utilized in other embodiments. For example,  FIG. 4  depicts an exploded view of a pair of locking pliers  360  that includes a lower handle  370  and a linkage  380  with a linkage bar  385 , which may be locked in place relative to one another by a pivot latch  390 , as described in greater detail below. Other components of the locking pliers  360  may be similar to corresponding components of the locking pliers  10 , and as such, are labeled identically to those components of the locking pliers  10  depicted in  FIG. 1 . For example, the locking pliers  360  include the upper handle  20  having the first end  30  and the second end  40 . The upper jaw  50  is received in the first end  30 , while the adjustment knob  230  is received in the second end  40 . The locking pliers  360  also includes the lower jaw  70 , pivotally coupled to the upper handle  20  by the first pivot pin  60 , that extends through the upper handle pivot holes  90  of the upper handle  20  and the first pivot hole  80  of the lower jaw  70 . Additionally, the spring  190  is coupled to the upper handle  20  and the lower jaw  70 , with the first end  200  being received in the receiving aperture  210  of the lower jaw  70 , and the second end  220  being received in the upper handle  20 . 
     As shown, the lower handle  370  of the locking pliers  360  is pivotally coupled to the lower jaw  70 . In particular, the lower jaw  70  is received within the lower handle  370  with first lower handle pivot holes  400  of the lower handle  370  aligned with the second pivot hole  120  of the lower jaw  70 , so that the second pivot pin  130  may be inserted therethrough to pivotally couple the lower jaw  70  to the lower handle  370 . The linkage bar  385  contains an associated lower linkage pivot hole  410 , which is received between second lower handle pivot holds  420  of the lower handle  370 . Additionally, pivot latch holes  430  of the pivot latch  390  may also be aligned with the lower linkage pivot hole  410  and the second lower handle pivot holes  420 , so that the third pivot pin  180  may be inserted therethrough, pivotally coupling the lower handle  370 , the linkage bar  385 , and the pivot latch  390  together. With such an alignment, the pivot latch  390  may rotate about the pivot pin  180 , and as such may be selectively positioned to engage both a linkage latch receptacle  440  in the pivot latch  390  and lower handle latch receptacles  450  in the lower handle  370 , which would lock the linkage bar  385  to the lower handle  370 , preventing movement of the linkage bar  385  from the overcenter locked position. Specifically, a pivot latch bar  460  extending between pivot latch flanges  470  containing the pivot latch holes  430  may rotate into the aligned linkage latch receptacle  440  and lower handle latch receptacles  450  when the linkage bar  385  is in the overcenter locked position, thus preventing pivotal motion between the linkage bar  385  and the lower handle  370  to move the linkage bar  385  out of the overcenter locked position. In an embodiment, such movement of the pivot latch  390  may be effectuated by manipulation of handles  475  extending from the pivot latch flanges  470  for engagement by a finger of a user of the locking pliers  360 . To allow the locking pliers  360  to be subsequently unlocked, the pivot latch  390  may be rotated so that the pivot latch bar  460  disengage from the lower handle latch receptacles  450  and the linkage latch receptacle  440 , disconnecting the connection between the linkage bar  385  and the lower handle  370 . In the illustrated embodiment, the pivot latch bar  460  is configured to be received in a second linkage latch receptacle  480  when the pivot latch  390  is rotated so as to not interfere with the pivotal motion of the linkage bar  385 . 
     Because the locking pliers  360  has an increased number of pivoting or otherwise rotating members about the third pivot pin  180 , in the illustrated embodiment a washer  490  is additionally provided to distribute the load on the third pivot pin  180 , reduce wear, or otherwise act as a spacer. It may be appreciated, however, that washers such as the washer  490  are optional, and may be found associated with the other pivot pins, or may be omitted, across various embodiments. In various embodiments, other elements of the linkage bar  385  and the lower handle  370  may generally resemble and function in a manner similar to corresponding elements of the locking pliers  10 . For example, the linkage bar  385  includes an upper linkage pivot  500  which similarly to upper linkage pivot  150  would be received in the upper handle  20  at a position that is modifiable by the adjustment knob  230 . Additionally, the lower handle  370  includes third lower handle pivot holes  510  that may be aligned with the release lever pivot hole  270  of the release lever  240  so that the release lever pivot pin  250  may be inserted therethrough to pivotally couple the release lever  240  to the lower handle  370 . As shown in the embodiment of  FIG. 4 , however, in some embodiments the linkage bar  385  may include a release lever receiving region  520  configured to enhance the mechanical advantage provided by the fulcrum point  280  of the release lever  240  as it engages the linkage bar  385  to move the linkage bar  385  out over the overcenter locked position. 
       FIGS. 5 and 6  depict side views of the locking pliers  360  as assembled. Specifically,  FIG. 5  illustrates the locking pliers  360  where the pivot latch  390  is in the unlocked position, such that the linkage bar  385  may freely move into and out of the overcenter position. Accordingly, pivot latch bar  460  (obscured in  FIG. 5 ) is positioned to be out of the plane of the alignment between the lower handle latch receptacles  450  and the corresponding linkage latch receptacle  440  (also obscured in  FIG. 5 ) in the linkage bar  385 , so that the linkage bar  385  may move between the overcenter, top dead center, and relaxed jaw-opening positions. Alternatively,  FIG. 6  depicts the pivot latch  390  in the locked position, such that the pivot latch bar  460  is positioned in the plane of alignment between the lower handle latch receptacles  450  and the corresponding linkage latch receptacle  440 , preventing the linkage bar  385  from moving relative to the lower handle  370 , and thus holding the linkage bar  385  in the overcenter locked position. 
     Various components of the locking pliers  10 , the locking pliers  360 , variations thereof, or other such embodiments may each be of any suitable construction or configuration, including but not limited to being formed from metal, plastic, elastomer, wood or combinations thereof. In some embodiments, the handles (i.e. the upper handle  20  and/or the lower handles  100  or  370 ) may be at least partially wrapped in a grip material, including but not limited to rubber. Additionally, while in the illustrated embodiment the linkage latch  290  and the pivot latch  390  are configured to couple the linkage bars  145  or  385  to the lower handles  100  or  370 , in other embodiments the linkage latch  290 , the pivot latch  390 , variations thereof, or other such embodiments may be configured to couple the linkages to the upper handle  20 , the lower jaw  70 , the upper jaw  50 , or any other appropriate location of the locking pliers, so as to selectively prevent movement of the linkage from the overcenter lock position. 
       FIGS. 7-24  provide another embodiment of the locking pliers having a mechanism for preventing movement of a linkage of the locking pliers from an overcenter locked position. 
       FIGS. 7-12  depict various views of a pair of locking pliers  700  that includes a lower handle  800  and a linkage  840  with a linkage member  845 , which may be locked in place relative to one another by a lock assembly  1000 , as described in greater detail below. Other components of the locking pliers  700  may be similar to corresponding components of the locking pliers  10  depicted in  FIG. 1 , and as such, are labeled identically to those components of the locking pliers  10 . For example, the locking pliers  700  includes an upper handle  720  having the first end  30  and the second end  40 . An upper jaw  750  is received in the first end  30 , while an adjustment knob  930  is received in the second end  40 . The locking pliers  700  also includes a lower jaw  770 , pivotally coupled to the upper handle  720  by a first pivot pin  760 , that extends through the upper handle pivot holes  90  of the upper handle  720  and the first pivot hole  80  of the lower jaw  770 . Additionally, the spring  190  (shown in  FIG. 12 ) is coupled to the upper handle  720  and the lower jaw  770 , with the first end  200  being received in the receiving aperture  210  of the lower jaw  770 , and the second end  220  being received in the upper handle  720 . A second pivot pin  830  is received by both the first lower handle pivot holes  110  and the second pivot hole  120  of the lower jaw  770 , to pivotally couple the lower handle  800  and the lower jaw  770 . 
     In various embodiments, some elements of the linkage member or bar  845  and the lower handle  800  may generally resemble and function in a manner similar to corresponding elements of the locking pliers  10 . For example, referring to  FIG. 13 , the linkage member  845  includes an upper linkage pivot  500  which similarly to the upper linkage pivot  150  would be received in the upper handle  720  at a position that is modifiable by the adjustment knob  930 . Additionally, the lower handle  800  includes third lower handle pivot holes  260  that may be aligned with the release lever pivot hole  270  of the release lever  940  so that a release lever pivot pin  850  may be inserted therethrough to pivotally couple the release lever  940  to the lower handle  800 . In the illustrated embodiment of  FIGS. 14 and 15 , the lower handle  800  includes second lower handle pivot holes  170 , surrounding a region in which the lower linkage pivot hole  160  is inserted into, so that the second lower handle pivot holes  170  are aligned with the lower linkage pivot hole  160 . A third pivot pin  880  may therefore be inserted through both the second lower handle pivot holes  170  and the lower linkage pivot hole  160 , such that the linkage member  845  couples the lower handle  800  to the upper handle  720 , and may push or pull on the assembly of the lower handle  800  and the lower jaw  770  to move the locking pliers  10  into and out of a relaxed jaw-opening position, a top-dead-center position, and the overcenter jaw-closing position. 
     In one embodiment, the lock assembly  100   o  includes a lock member  1002 . In one embodiment, movement of the lock member  1002  from the locking configuration (as shown in  FIGS. 7, 8 and 10 ) to the release configuration (as shown in  FIGS. 9, 11 and 12 ) requires sequential movement of the lock member in a first direction and then in a second direction. In one embodiment, the second direction is different than the first direction. In one embodiment, the first direction and the second direction are perpendicular to one another. 
     In one embodiment, the first direction generally refers to a direction into the plane of the paper/page in  FIG. 7 . In one embodiment, the first direction is a direction perpendicular to a plane of the movement of the linkage  845 . In one embodiment, the plane of movement of the linkage  845  is generally parallel to a plane of the paper/page, for example, in  FIG. 7 . In one embodiment, the movement of the lock member  1002  in the first direction requires an axial pushing of the lock member  1002  in a direction perpendicular to the plane of the movement of the linkage  845 . 
     In one embodiment, the second direction generally refers to a rightward side direction within the plane of the paper/page in  FIG. 7 . In one embodiment, the vector of the second direction (of motion) is in a plane parallel to the plane created by the movement (e.g., rotational motion) of the linkage. In one embodiment, the movement of the lock member  1002  in the second direction requires a lateral sliding of the lock member  1002  in the plane of the movement of the linkage  845 . 
     In one embodiment, the lock member  1002  is configured to have more than one (or a single) degree of freedom. In one embodiment, this configuration of the lock member  1002  requires a user to axially push or depress the lock member  1002  and then laterally slide the lock member  1002  to engage or disengage the lock member  1002 . This configuration, thus, prevents the lock member  1002  from accidently being engaged or disengaged. This configuration of the lock member also prevents accidental opening of the pliers  700 . 
     In one embodiment, referring to  FIG. 13 , the linkage member  845  includes a lock member receiving recess  845   a . In one embodiment, the lock member receiving recess  845   a  is constructed and arranged to receive a portion ( 1002   a ) of the lock member  1002 , when the lock member  1002  is in its locking configuration. The portion  1002   a  and other portions of the lock member  1002  are described in detail below with respect to  FIGS. 19-22 . 
     In one embodiment, the lock member receiving recess  845   a  is shaped and sized such that its inner surface  847  is configured to engage with an outer surface of the portion  1002   a  of the lock member  1002 . In one embodiment, the lock member receiving recess  845   a  and the portion  1002   a  of the lock member  1002  are shaped and sized to form a locking engagement to lock the lock member  1002  in its locking configuration. 
     In one embodiment, referring to  FIGS. 14 and 15 , the lower handle  800  includes two elongated openings  803  that are axially aligned with each other. One of the elongated openings  803  is shown in  FIGS. 14 and 15 . In one embodiment, each of the elongated openings  803  of the lower handle  800  includes an hour glass shaped configuration. This configuration of the lower handle  800  enables the lock member  1002  to be located in either the locking configuration or the release configuration. 
     In one embodiment, each elongated opening  803  of the lower handle  800  includes opposing end openings  803   a  and  803   b  and a center opening  803   c  therebetween. Each of the opposing end openings  803   a  and  803   b  are enlarged relative to the center opening  803   c . When the lock member  1002  is in the locking configuration, the lock member  1002  is received by one of the enlarged opposing end openings  803   a  of the lower handle  800  and the lock receiving recess  845   a  of the linkage  845 . When the lock member  1002  is in the release configuration, the lock member  1002  is received by the other of the enlarged opposing end openings  803   b  of the lower handle  800 . 
     In one embodiment, the lock member  1002  is configured to laterally slide between the locking configuration and the release configuration in the second direction. In one embodiment, the center opening  803   c  of the lower handle  800  is configured to facilitate the lateral sliding movement of the lock member  1002  between the locking configuration and the release configuration. That is, when the lock member  1002  is moved between the locking configuration and the release configuration, the lock member  1002  is configured to move from one of the end openings  803   a  and  803   b  to the other of the end openings  803   a  and  803   b  through the center opening  803   c  of the lower handle  800 . 
     In one embodiment, the end openings  803   a  and  803   b  are constructed and arranged to receive the portion  1002   a  of the lock member  1002 , when the lock member  1002  is either in its locking configuration or in its release configuration. In one embodiment, each of the end openings  803   a  and  803   b  is shaped and sized such that its inner surface is configured to engage with an outer surface of the portion  1002   a  of the lock member  1002 . In one embodiment, each of the end openings  803   a  and  803   b  and the portion  1002   a  of the lock member  1002  are shaped and sized to form a locking engagement to lock the lock member  1002  in its locking configuration or in its release configuration. 
     In one embodiment, referring to  FIGS. 19-24 , the lock assembly  1000  includes the lock member  1002 , a manually engageable member  1004  that is operatively associated with the lock member  1002 , and a spring  1006 . In one embodiment, the lock assembly  1000  may also include a washer  1008  and a movement limiting member or collar member  1012 . The movement limiting member or collar member  1012  is described below in detail with respect to  FIGS. 16-18 . 
     In one embodiment, the lock member  1002  includes a first sized lock portion  1002   a  and a second sized lock portion  1002   b . In one embodiment, the first and second sized lock portions  1002   a  and  1002   b  have different diameters. In one embodiment, the first sized lock portion  1002   a  of the lock member is a larger diameter lock portion and the second sized lock portion  1002   b  is a smaller diameter lock portion. 
     In one embodiment, the steps between the different sized or diameter portions  1002   a  and  1002   b  of the lock member  1002  are chamfered  1002   e  to prevent catching when the lock member  1002  travels axially in the first direction. In one embodiment, the lock member  1002  is constructed and arranged with varying diameter portions to provide interference between the lower handle  800  and the linkage  845  to prevent rotation between them. 
     The lock member  1002  is configured to extend through the lock member receiving recesses  803   a  of the lower handle  800  that are positioned to be in alignment with the lock member receiving recess  845   a  of the linkage member  845  when the linkage member  845  is in the overcenter jaw-closing position. 
     In one embodiment, the first sized lock portion  1002   a  of the lock member  1002  is shaped and sized such that its outer surface is configured to engage with inner surfaces of the lock member receiving recess  845   a  of the linkage member  845  and the end opening  803   a  of the lower handle  800 , when the lock member  1002  is in locking configuration. In one embodiment, the first sized lock portion  1002   a  of the lock member  1002  is shaped and sized such that its outer surface is configured to engage with inner surfaces of the end opening  803   b  of the lower handle  800 , when the lock member  1002  is in release configuration. 
     In one embodiment, the second sized lock portion  1002   b  of the lock member  1002  and the center opening  803   c  of the lower handle  800  are shaped and sized such that the second sized lock portion  1002   b  of the lock member  1002  laterally slides in the center opening  803   c  of the lower handle  800  when the lock member  1002  is moved between the locking configuration and the release configuration. 
     In one embodiment, the lock member  1002  may also include a third sized portion  1002   c  positioned adjacent the second sized lock portion  1002   b , another second sized portion  1002   b ′, a fourth sized portion  1002   d  and another first sized portion  1002   a ′ between the fourth sized portion  1002   d  and the second sized portion  1002   b ′. In one embodiment, the third sized portion  1002   c  is positioned at one end of the lock member  1002  and the fourth sized portion  1002   d  is positioned at the other end of the lock member  1002 . In one embodiment, the first sized lock portion  1002   a  is positioned between the second sized lock portion  1002   b  and the second sized portion  1002   b ′. In one embodiment, the second sized lock portion  1002   b  and the second sized portion  1002   b ′ have same shape, size and cross-sectional configuration. In one embodiment, the first sized lock portion  1002   a  and the first sized portion  1002   a ′ have same shape, size and cross-sectional configuration. 
     In one embodiment, the second sized portion  1002   b ′ of the lock member  1002  and the rear, center opening  803   c  (that is axially aligned with the front, center opening  803   c  that receives the second sized lock portion  1002   b ) of the lower handle  800  are shaped and sized such that the second sized portion  1002   b ′ of the lock member  1002  laterally slides in the corresponding rear, center opening  803   c  of the lower handle  800  when the lock member  1002  is moved between the locking configuration and the release configuration. 
     In one embodiment, the first sized portion  1002   a ′ of the lock member  1002  and the rear, lock member receiving recesses  803   a ,  803   b  (that are axially aligned with the front, lock member receiving recesses  803   a ,  803   b  that receive the first sized lock portion  1002   a ) of the lower handle  800  are shaped and sized such that the first sized portion  1002   a ′ of the lock member  1002  is received by one of the rear, lock member receiving recesses  803   a ,  803   b  when the lock member  1002  is in its locking configuration and is received by the other of the rear, lock member receiving recesses  803   a ,  803   b  when the lock member  1002  is in its release configuration. In one embodiment, each of the rear, lock member receiving recesses  803   a ,  803   b  of the lower handle  800  is shaped and sized such that its inner surface is configured to engage with an outer surface of the first sized portion  1002   a ′ of the lock member  1002 . In one embodiment, the rear, lock member receiving recesses  803   a ,  803   b  of the lower handle  800  and the first sized portion  1002   a ′ of the lock member  1002  are shaped and sized to form a locking engagement to lock or maintain the lock member  1002  in its locking configuration or in its release configuration. 
     In one embodiment, the fourth sized portion  1002   d  of the lock member  1002  and an opening  1017  (as shown in  FIGS. 16-18 ) of the collar member  1012  are shaped and sized such that the fourth sized portion  1002   d  of the lock member  1002  laterally slides in the opening  1017  of the collar member  1012  when the lock member  1002  is moved between the locking configuration and the release configuration. 
     In one embodiment, the third sized portion  1002   c  of the lock member  1002  is received by a recess  1005  (as shown in  FIG. 23 ) disposed on a rear surface  1009  (as shown in  FIG. 23 ) of the manually engageable member  1004  so as to operatively connect the lock member  1002  and the manually engageable member  1004 . As the lock member  1002  and the manually engageable member  1004  are operatively connected to each other, actuation of the manually engageable member  1004  causes the movement of the lock member  1002 . 
     In one embodiment, the manually engageable member  1004  is positioned on a first end  1011  of the lock member  1002 . In one embodiment, the manually engageable member  1004  is configured to act as an actuator for the lock assembly  1000 . In one embodiment, the manually engageable portion  1004  includes a recess  1007  on the rear surface  1009  thereof. In one embodiment, the recess  1007  of the manually engageable portion  1004  is configured to receive at least a portion of the spring  1006  so as to operatively connect the manually engageable portion  1004  to the spring  1006 . In one embodiment, the manually engageable portion  1004  is operatively connected to both the spring  1006  and the lock member  1002 . 
     Referring to  FIGS. 23-24 , in one embodiment, the manually engageable member  1004  includes a non-axially symmetric configuration. In one embodiment, this non-axially symmetric configuration of the manually engageable member  1004  is more intuitive for an end user. In one embodiment, the manually engageable member  1004  is not axially symmetric with respect to an axis S-S (as shown in  FIG. 23A ). In one embodiment, the manually engageable member  1004  is not symmetric under 180 degree rotation about the axis S-S. In one embodiment, the manually engageable member  1004  includes a protrusion member  1073  (on a front surface  1075  of the manually engageable member  1004 ) that is constructed and arranged to provide comfort to a user during use and to be intuitive to use. In one embodiment, an angle A (as shown in  FIG. 24 ) of the hump or the protrusion member  1073  with respect to an axis A-A is constructed and arranged to align more comfortably with the users thumb, when the manually engageable member  1004  is constrained by the movement limiting member or collar member  1012 .  FIGS. 25, 25A and 26  show views of another exemplary manually engageable member of the lock assembly. In one embodiment, the manually engageable member  1004  is also not axially symmetric about an axis S-S. 
     In one embodiment, this non-axially symmetric configuration of the manually engageable member  1004  (of  FIGS. 23-24 and 25-26 ) enables the movement limiting member or collar member  1012  to restrict the rotation of the manually engageable member  1004 . In one embodiment, this non-axially symmetric configuration of the manually engageable member  1004  (of  FIGS. 23-24 and 25-26 ) also allows for the placement of the protrusion member  1073 . In one embodiment, the protrusion member  1073  may be a humped feature that is constructed and arranged to provide comfort to a user during use and to be intuitive to use by the user. 
       FIGS. 27 and 28  show views of yet another exemplary manually engageable member of the lock assembly. In one embodiment, the manually engageable member  1004  is axially symmetric about an axis S-S. 
     In one embodiment, the manually engageable member  1004  is constructed and arranged such that the user may manually actuate the manually engageable member  1004  to translate or move the lock member  1002  axially in the first direction, and then move the lock member  1002  in the second direction (i.e., radial direction). In one embodiment, the manually engageable member  1004  is configured to slide in the second direction and of a distance long enough to indicate clearly to the user whether the lock assembly is engaged or not. 
     In one embodiment, referring to  FIGS. 10, 16, 17, 24 , the lock assembly  1000  includes an indicator  1025  that configured to provide a first indication to indicate to the user when the lock member is in the locking configuration and a second indication to indicate to the user when the lock member is in the release configuration. In one embodiment, the first indication and the second indication are visual indications. In one embodiment, the indicator  1025  may include a first indicator portion  1027  and second indicator portions  1029   a  and  1029   b . In one embodiment, the first indicator portion  1027  and the second indicator portion  1029   a  together provide the first indication to the user that the lock member is in the locking configuration. In one embodiment, the first indicator portion  1027  and the second indicator portion  1029   b  together provide the second indication to the user that the lock member is in the release configuration. In one embodiment, the first indicator portion  1027  is disposed on the manually engageable portion  1004  and the second indicator portions  1029   a  and  1029   b  are disposed on the collar member  1012 . 
     In one embodiment, the indicator may be positioned on, for example, a surface  1010  (as shown in  FIGS. 12 and 22 ) of the lower handle such the lateral sliding movement of the lock assembly to its locking configuration reveals the locking configuration indicator and the lateral sliding movement of the lock assembly to its release configuration reveals the release configuration indicator. For example, in one embodiment, the locking configuration indicator is positioned adjacent the lock member receiving recess  803   b  of the lower handle  800  and the release configuration indicator is positioned adjacent the lock member receiving recess  803   a  of the lower handle  800 . 
     In one embodiment, the washer  1008  is provided in the lock assembly  1000  to distribute the load on the lock member  1002 , reduce wear, or otherwise act as a spacer. It may be appreciated, however, that washers such as the washer  1008  are optional, and may be found associated with the other pivot pins, or may be omitted, across various embodiments. In one embodiment, when assembled in the lock assembly  1000 , the washer member  1008  is positioned between the lower handle  800  and the spring  1006 . In one embodiment, when assembled in the lock assembly  1000 , the washer member  1008  is positioned to engage with the surface  1010  of the lower handle  800  on one side and to engage with a portion of the spring  1006  on the other side. 
     In one embodiment, referring to  FIGS. 16-18 , the movement limiting member or collar member  1012  is constructed and arranged to limit the movement or rotation of the manually engageable member  1004 . In one embodiment, the movement limiting member or collar member  1012  is configured to allow the non-axially symmetric configuration of the manually engageable member  1004 . In one embodiment, as shown in  FIG. 22 , the movement limiting member or collar member  1012  is configured to partially encase the manually engageable member  1004 , the spring  1006 , and/or the lock member  1002 . In one embodiment, the movement limiting member or collar member  1012  is also configured to protect the manually engageable member  1004 , the spring  1006 , and/or the lock member  1002  from wear by partially encasing them. 
     In one embodiment, the movement limiting member or collar member  1012  includes openings  1033  and  1033 ′ that are configured to be aligned with the second lower handle pivot holes  170  of the lower handle  800  and the lower linkage pivot hole  160  of the linkage member  845  and that are configured to receive the third pivot pin  880  therein. In one embodiment, the movement limiting member or collar member  1012  includes openings  1035  and  1035 ′ that are configured to be aligned with third lower handle pivot holes  260  of the lower handle  800  and the release lever pivot hole  270  of the release lever  940  and that are configured to receive the release lever pivot pin  850  therein. In one embodiment, the pivot pins  880  and  850  are configured to connect the movement limiting member or collar member  1012  to the lower handle  800 . In one embodiment, the movement limiting member or collar member  1012  may be optional. 
     In one embodiment, the movement limiting member or collar member  1012  includes an elongated opening  1013  on a front surface portion  1015  thereof and the elongated opening  1017  on a rear surface portion  1019  thereof. In one embodiment, the front elongated opening  1013  and the rear elongated opening  1017  have different shaped configurations. In one embodiment, the front elongated opening  1013  is constructed and arranged to receive a portion of the manually engageable member  1004  and the rear elongated opening  1017  is constructed and arranged to receive a portion of the fourth sized portion  1002   d  of the lock member  1002 . 
     In one embodiment, the front elongated opening  1013  is shaped and sized to enable the Manually engageable member  1004  to laterally slide therethrough when the lock assembly  1000  moves between the locking and release configurations. In one embodiment, the rear elongated opening  1017  is shaped and sized to enable the fourth sized portion  1002   d  of the lock member  1002  to laterally slide therethrough when the lock assembly  1000  moves between the locking and release configurations. 
     In one embodiment, as shown in  FIGS. 16-18 , the movement limiting member or collar member  1012  may include a U-shaped member  1085  that is configured to surround a portion of the lower handle  800 . In one embodiment, as shown in  FIGS. 9, 12 and 22 , the U-shaped member  1085  of the movement limiting member or collar member  1012  may be optional. For example, in one embodiment as shown in  FIGS. 9, 12 and 22 , the movement limiting member or collar member  1012  may include two separate members (a front and a rear member) that are not integrally formed. In one embodiment, the front and the rear members of the movement limiting member or collar member  1012  are connected to the lower handle  800  using the third pivot pin  880  and the release lever pivot pin  850 . That is, as shown in  FIGS. 9, 12 and 22 , the movement limiting member or collar member  1012  does not include the U-shaped member  1085  (as shown in  FIGS. 16-18 ). In one embodiment, the movement limiting member  1012  may be shaped and configured differently as may be seen by a comparison of the movement limiting member or collar member  1012  of  FIG. 9  with that of  FIGS. 12 and 22 . In one embodiment, other movement limiting members or mechanisms may be used to limit the movement or rotation of the manually engageable member  1004 . 
     In one embodiment, the spring  1006  is configured to provide a spring force to the lock assembly  1000  such that when the lock member  1002  is moved to its locking configuration, the spring force urges the lock member  1002  into its locking configuration in which the first sized lock portion  1002   a  of the lock member  1002  is received in a locking engagement by the lock member receiving recess  803   a  of the lower handle  800  and the lock member receiving recess  845   a  of the linkage  845 . In one embodiment, the spring  1006  is configured to be positioned between the manually engageable member  1004  and a portion of the lower handle  800 . 
     In one embodiment, the spring  1006  is configured to provide the spring force on the lock assembly  1000  such that when the lock member  1002  is moved to its release configuration, the spring force urges the lock member  1002  into its release configuration in which the first sized lock portion  1002   a  of the lock member  1002  is received in a locking engagement by the lock member receiving recess  803   b  of the lower handle  800 . 
     In one embodiment, the spring  1006  is a spring member. In one embodiment, the spring  1006  is a coil or a helical spring member. In one embodiment, the spring  1006  is a compression spring. 
     In one embodiment, the spring  1006  is configured to maintain the lock member  1002  in an axially constrained position until a threshold force greater than a force of the spring  1006  is applied to the manually engageable member  1004 . In one embodiment, the spring force provided by the spring  1006  is configured to impede the movement of the lock member  1002  from its locking configuration or its release configuration. In order to move the lock member  1002  from its locking configuration or its release configuration, the spring force of the spring  1006  must be overcome. In one embodiment, an application of a threshold force on the lock member  1002  in the first direction enables the lock member  1002  to overcome the spring force provided by the spring  1006 . When the spring force is overcome, the lock member  1002  is configured to move between the locking configuration and the release configuration. 
     In one embodiment, the manually engageable member  1004  is biased forwardly (i.e., in the direction out of the plane of the paper in  FIG. 7 ) by the spring  1006 . In one embodiment, the spring  1006  is configured to function as a return spring. In one embodiment, the spring  1006  may be configured to function as a force transmitting mechanism for transmitting forces between the manually engageable member  1004  and the other components of the lock assembly  1000 . 
     The operation of the pliers  700  is discussed with reference to  FIGS. 7-12 . As shown in  FIGS. 7, 8 and 10 , the lock member  1002  is in the locking configuration. When the lock member  1002  is in the locking configuration, the lock member  1002  is configured to prevent pivoting movement of the lower handle  800  from the closed configuration and retains the jaws  750  and  770  in the closed position. That is, when in the locking configuration, the lock member  1002  is configured to prevent the linkage member  845  from moving relative to the lower handle  800 , and thus holding the linkage member  845  in the overcenter locked position. 
     Also, when in the locking configuration, the lock member  1002  is positioned such that the first sized lock portion  1002   a  is received in a locking engagement by both the lock member receiving recess  845   a  of the linkage member  845  and the lock member receiving recesses  803   a  of the lower handle  800 . In one embodiment, when the larger diameter lock portion  1002   a  is positioned in the lock member receiving recess  845   a  of the linkage  845 , the linkage  845  at least partially surrounds the larger diameter lock portion  1002   a , preventing the linkage member  845  from moving out of the jaw-closing position due to the engagement between the lock member  1002  and the lock member receiving recess  845   a  of the linkage  845 . 
     When the lock member  1002  is in its locking configuration, a spring force is applied on the manually engageable member  1004  by the spring  1006  in a direction out of the plane of the paper in  FIG. 7 . The applied spring force moves the manually engageable member  1004  in the direction out of the plane of the paper in  FIG. 7 . As the manually engageable member  1004  and the lock member  1002  are operatively connected to each other, the applied spring force also moves and positions the lock member  1002  such that the first sized lock portion  1002   a  is received in a locking engagement by both the lock member receiving recess  845   a  of the linkage member  845  and the lock member receiving recesses  803   a  of the lower handle  800 . 
     In one embodiment, to move the lock member  1002  from its locking configuration, the user manually actuates the manually engageable member  1004  of the lock assembly  1000 . In one embodiment, the manually engageable member  1004  of the lock assembly  1000  is manually actuated by the user to move the lock assembly  1000  in the first direction. In one embodiment, the manually engageable member  1004  of the lock assembly  1000  is manually actuated by the user to axially push of the lock assembly  1000  in a direction perpendicular to the plane of the movement of the linkage  845 . 
     In one embodiment, application of a threshold force (by a user) on the manually engageable member  1004  in the first direction enables the manually engageable member  1004  to overcome the spring force provided by the spring  1006 . In one embodiment, the threshold force is an axial force applied on the manually engageable member  1004 . 
     When the spring force is overcome, the lock member  1002  may be (axially and) slidably positioned such that the smaller diameter lock portion  1002   b  is generally surrounded by the lock member receiving recess  845   a  of the linkage member  845 . The linkage member  845  may freely move from the overcenter jaw-closing position, as the smaller diameter lock portion  1002   b  may pass through the lock member receiving recess  845   a  as the linkage bar  145  moves into and out of the overcenter jaw-closing position. 
     Also, depressing the manually engageable member  1004  causes the lock member  1002  to be axially or slidably positioned such that the smaller diameter lock portion  1002   b  is positioned in the end opening  803   a  of the lower handle  800  and the second diameter portion  1002   b ′ is positioned in the rear, end opening  803   a  of the lower handle  800 . 
     With the manually engageable member  1004  still being depressed, the user may laterally slide the manually engageable member  1004  in the second direction from the locking configuration to the release configuration. As the manually engageable member  1004  and the lock member  1002  are operatively connected to each other, the laterally sliding of the manually engageable member  1004  causes the laterally sliding movement of the lock member  1002 . 
     During the lateral sliding movement of the lock member  1002  from the locking configuration to the release configuration, the second diameter lock portion  1002   b  is configured to slide through the center opening  803   c  of the lower handle  800 . That is, the second diameter lock portion  1002   b  of the lock member  1002  is configured to move from the end opening  803   a  to the other end opening  803   b  through the center opening  803   c  of the lower handle  800 . At the same time, the second diameter portion  1002   b ′ of the lock member  1002  is configured to slide through the rear, center opening  803   c  of the lower handle  800 . 
     When the second diameter lock portion  1002   b  of the lock member  1002  is received in the end opening  803   b  of the lower handle  800 , the user may release the manually engageable member  1004 . When the threshold force applied by the user on the manually engageable member  1004  is released, the spring force of the spring  1006  acts on the manually engageable member  1004  to push or force the manually engageable member  1004  in a direction out of the plane of the paper in  FIG. 7 . As the manually engageable member  1004  and the lock member  1002  are operatively connected to each other, the applied spring force also moves and (axially/slidably) positions the lock member  1002  such that the first sized lock portion  1002   a  is received in a locking engagement by the lock member receiving recesses  803   b  of the lower handle  800 . Thus, the lock assembly  1000  is moved to its release configuration. The lock assembly  1000  remains in this release configuration until the user manually actuates the manually engageable member  1004  of the lock assembly  1000 . 
     In one embodiment, to move the lock member  1002  from its release configuration, the user manually actuates (axially pushes it in the first direction) the manually engageable member  1004  of the lock assembly  1000 . 
     In one embodiment, application of a threshold force (by a user) on the manually engageable member  1004  in the first direction enables the manually engageable member  1004  to overcome the spring force provided by the spring  1006 . When the spring force is overcome, the lock member  1002  may be (axially and/or) slidably positioned such that the smaller diameter lock portion  1002   b  is positioned in the end opening  803   b  of the lower handle  800  and the second diameter portion  1002   b ′ is positioned in the rear, end opening  803   b  of the lower handle  800 . 
     With the manually engageable member  1004  still being depressed, the user may laterally slide the manually engageable member  1004  from the release configuration to the locking configuration in a direction (leftward side direction within the plane of the paper in  FIG. 7 ) that is opposite to the second direction. During the lateral sliding movement of the lock member  1002  from the release configuration to the locking configuration, the second diameter lock portion  1002   b  of the lock member  1002  is configured to move from the end opening  803   b  to the other end opening  803   a  through the center opening  803   c  of the lower handle  800 . At the same time, the second diameter portion  1002   b ′ of the lock member  1002  is configured to slide through the rear, center opening  803   c  of the lower handle  800 . 
     When the second diameter lock portion  1002   b  of the lock member  1002  is received in the end opening  803   a  of the lower handle  800 , the user may release the manually engageable member  1004 . When the threshold force applied by the user on the manually engageable member  1004  is released, the spring force of the spring  1006  acts on the manually engageable member  1004  to push or force the manually engageable member  1004  in a direction out of the plane of the paper in  FIG. 7 . The applied spring force also moves and (axially/slidably) positions the lock member  1002  such that the first sized lock portion  1002   a  is received in a locking engagement by both the lock member receiving recesses  803   a  of the lower handle  800  and the lock member receiving recess  845   a  of the linkage  845 , preventing the linkage member  845  from moving out of the jaw-closing position. Thus, the lock assembly is moved to its locking configuration. The lock assembly  1000  remains in this locking configuration until the user manually actuates the manually engageable member  1004  of the lock assembly  1000 . 
     Although the patent application has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the patent application is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present patent application contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.