Abstract:
A one-handed ratcheting C-clamp is provided. The C-clamp incorporates a spring loaded handle mechanically coupled to a ratcheting mechanism. The ratcheting mechanism has a plurality of gear teeth that engage the threads of a corresponding rod disposed through a hole formed in one section of the C-shaped C-clamp. The handle rotates the bidirectional ratchet such that the threaded rod is lowered or raised within the hole of the C-shaped C-clamp. A button located in the side of the handle may release the ratchet mechanism pawl to provide axial sliding engagement of the rod to a corresponding work piece. The handle and corresponding ratchet mechanism secure the rod against the work piece. Further tightening engagement of the work piece is accomplished via a lever located on a top portion of the rod.

Description:
REFERENCE TO PRIORITY DOCUMENT 
     This application claims priority of co-pending U.S. Provisional Patent Application Ser. No. 60/948,897 filed on Jul. 10, 2007. The disclosure of the Provisional Patent Application is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     The present invention generally relates to a ratcheting C-clamp. More particularly, the present invention relates to a one-handed bidirectional ratcheting C-clamp capable of tightening a work piece via the ratchet mechanism and a lever and corresponding screw mechanism. 
     C-clamps are generally known in the art. A conventional C-clamp typically includes a “C” shaped member constructed from cast iron or another hard metal alloy material. One end of the C-shaped member has a threadable hole therein configured to receive a corresponding threaded rod. The rod is screwed through the hole toward an opposite end of a C-shaped member having a corresponding flat surface. The forward motion of the threaded rod is governed by the thread-by-thread screwing mechanism and is typically slow. The distance the rod moves with each turn is limited to the pitch of the screw threads. Faster movement is accomplished by incorporating a nut or other structure that enables only partial threading of the rod. Other mechanisms may allow the rod to completely disengage the threaded C-shaped member for axial movement therein. Accordingly, the flat end of the rod mates with the flat surface of the opposite end of the C-shaped member. Adjustment of the rod in this C-clamp is only accomplished by screwing the rod. 
     C-clamps are used in industry to secure a work piece or to secure several work pieces together. The work piece is placed between the flat end of the rod and the flat surface of the opposite end of the C-shaped member. The work piece is secured therebetween as the rod is screwed towards the flat surface of the C-shaped member. This squeezing or clamping action prevents movement of the work piece or prevents movement of several work pieces relative to one another. The C-clamp may include a pressure pad or vice jaw to further retain the work piece or the plurality of work pieces. 
     A common issue with known C-clamps is that the operation requires two hands. One hand holds the C-clamp assembly while the other hand turns a lever mounted to one end of the rod. The lever provides a higher mechanical advantage for screwing the rod through the hole end of the C-clamp. The lever allows the operator to obtain the necessary torque required to securely squeeze the work piece between the flat ends of the C-shaped member and the rod. Thus, a third hand or other retaining device is needed to assist the operator in order to hold the work piece in a steady position so that the operator may close the C-clamp therearound. Improvisations such as using a knee, a jury rig lever temporary welded to a work table, etc. are inadequate substitutes for the third hand. Such improvisations are also hazardous, time consuming and poor substitutes for other methods of holding the work piece in place. An alternative to using a third hand (necessarily requiring incorporation of a second person) is the use of an additional holding or retaining structure employed to clamp or retain the work piece prior to C-clamp application. 
     A one-hand operated C-clamp known in the art provides a mounted rack-held movable jaw that drops down against a work piece. The movable jaw is operated by gravity. The C-clamp further includes a cam-operated pawl that engages the rack via a hand-squeeze handle. The handle is used to increase the clamping pressure of the jaw against the bottom portion of the C-clamp. The C-clamp is locked into position with one stroke of the hand-squeeze handle. A lever in the jaw head rotates the jaw to obtain proper holding pressure when the clamping movement is insufficient. The C-clamp requires operating the lever with one hand while simultaneously holding the work piece with a second hand. Such a C-clamp is typically mounted to a table or other fixture. A disadvantage of such a C-clamp is that operators are unable to move the C-clamp into confined or narrow spaces where clamping may be desired. 
     SUMMARY 
     In view of the foregoing, there is a need for a C-clamp that is capable of tensioning a work piece or plurality of work pieces without the need of a third hand or other retaining device. Accordingly, the C-clamp frees the second hand to position or hold the work piece in place until firmly secured by the C-clamp. Such a C-clamp incorporates a spring actuated handle coupled to a ratchet mechanism that operates a rack and pinion gear mechanism for tensioning the rod portion of the C-clamp around the work piece. The C-clamp should further include a lever for screwingly tightening the C-clamp when further tensioning of the ratcheting mechanism is no longer obtainable. The C-clamp should also include a release mechanism to provide quick axial movement of the rod within one end of the C-shaped member. Moreover, such a C-clamp should be lightweight in construction, mobile, and capable of exerting sufficient force to properly tension a work piece within the clamp to prevent movement thereof. The C-clamp should also be relatively simply constructed to reduce the cost of manufacturing and simplify use and maintenance. 
     A ratcheting C-clamp is herein provided. The C-clamp of the present invention includes a spring loaded handle that operates the clamping mechanism with only one hand. The spring loaded handle is coupled to a ratchet mechanism threadingly engaged to the threads of a corresponding rod. Accordingly, the ratchet mechanism is bidirectional to allow an operator to elevate or descend the corresponding rod within a gap formed by the top and bottom portions of the C-shaped C-clamp. A lever integral to the rod provides an additional work piece tightening mechanism. When the ratcheting mechanism is no longer feasible, an operator may further screwingly tighten the rod via the lever. Moreover, an additional release button incorporated into the ratcheting mechanism disengages the ratchet pawl to facilitate free axial movement of the rod without interference or operation of the ratchet mechanism or the lever and corresponding screw. 
     The C-clamp of the present invention is operated by compressing a spring loaded handle toward the body portion of the C-clamp. The front end of the handle is mechanically coupled to one end of a ratchet mechanism. Movement of the handle causes simultaneous movement in the ratchet mechanism. Such movement operates the ratchet. Accordingly, the ratchet moves a set of teeth engaged to the threads of a corresponding rod. Counter-clockwise movement elevates the rod, while clockwise movement descends the rod within the gap formed between each side of the C-shaped C-clamp. The ratchet gears and rod threads engage to form a simple screw mechanism. Hence, an operator is able to properly locate a work piece between each side of the C-shaped member of the C-clamp while simultaneously tightening the rod around the work piece via the handle and ratchet mechanism. Once the rod is sufficiently tightened against the work piece such that the ratchet mechanism is no longer feasible for operation, the lever located on the top portion of the rod is further operable to further tighten the rod against the corresponding work piece. A button mounted in the side portion of the C-clamp disengages the pawl from the ratchet mechanism to facilitate axial movement of the rod without the need to use the ratchet mechanism or lever and screw. 
     In one aspect, there is disclosed an adjustable C-clamp, comprising: a main body; a threaded rod movably attached to main body; an actuator; a ratchet mechanism that mechanically couples the rod to the actuator, wherein actuation of the actuator drives the ratchet mechanism to cause axial movement of the rod toward or away from a workpiece; and a gear assembly connecting the ratchet mechanism to the rod. 
     In another aspect, there is disclosed an adjustable C-clamp, comprising: a main body; a threaded rod movably attached to main body; an actuator; and a ratchet mechanism that mechanically couples the rod to the actuator, wherein actuation of the actuator drives the ratchet mechanism to cause axial movement of the rod toward or away from a workpiece. 
     In another aspect, there is disclosed an adjustable C-clamp, comprising: a main body; a threaded rod movably attached to main body; an actuator; a ratchet mechanism that mechanically couples the rod to the actuator, wherein actuation of the actuator drives the ratchet mechanism to cause axial movement of the rod toward or away from a workpiece; and a quick-release member, wherein actuation of the quick-release member causes the ratchet mechanism to uncouple from the rod so that the rod can move freely toward or away from the workpiece. 
     Other features and advantages of the present invention will become apparent from the following more detailed description, when taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings illustrate the invention. In such drawings: 
         FIG. 1  is a side view of a C-clamp of the present invention; 
         FIG. 2  is a side view of the backside of the C-clamp of  FIG. 1 ; 
         FIG. 3  is an exploded side view of a C-clamp, illustrating attachment of a handle and ratchet mechanism to a C-shaped member; 
         FIG. 4  is a side view of the C-clamp in  FIG. 1 , illustrating the internal ratchet mechanism; 
         FIG. 5  is a side view of the C-clamp of  FIG. 2 , illustrating engagement of the ratchet mechanism with the threads of a rod; 
         FIG. 6  is a side view of a C-clamp, illustrating downward engagement of the ratchet mechanism; 
         FIG. 7  illustrates descending movement of the rod within the gap formed within the C-shaped member; 
         FIG. 8  is a side view of a C-clamp, illustrating upward engagement of the ratchet mechanism; 
         FIG. 9  illustrates ascending movement of the rod within the gap formed within the C-shaped member; 
         FIG. 10  is an enlarged view of the ratchet mechanism of  FIG. 6 , taken about the line  10 ; 
         FIG. 11  is an enlarged view of the ratchet mechanism of  FIG. 7 , taken about the line  11 , further illustrating descending movement of the rod relative to the ratchet mechanism; 
         FIG. 12  is an enlarged view of the ratchet mechanism in  FIG. 8 , taken about the line  12 ; 
         FIG. 13  is an enlarged view of the ratchet mechanism in  FIG. 9 , taken about the line  13 , further illustrating ascending movement of the rod relative to the ratchet mechanism; 
         FIG. 14  is a perspective cut-out view of the ratchet mechanism and gear coupler of the present invention; 
         FIG. 15  is an exploded perspective view further illustrating the components of the ratchet mechanism and the gear coupler; 
         FIG. 16  is an end view of a C-clamp, illustrating pawl engagement within the ratchet mechanism; 
         FIG. 17  is an alternate end view of  FIG. 16 , illustrating disengagement of the pawl from the ratchet mechanism; 
         FIG. 18  is an enlarged view of a plunger in  FIG. 3 , taken about the line  18 , further illustrating a compression spring located therein; and 
         FIG. 19  is an alternative view of  FIG. 18 , illustrating compression of the spring within the plunger. 
     
    
    
     DETAILED DESCRIPTION 
     As shown in the exemplary drawings for purposes of illustration, the present disclosure for a ratcheting C-clamp is generally referenced by the reference numeral  20 . Turning now to the representative figures in the specification,  FIG. 1  illustrates a side view of the C-clamp  20  of the present disclosure. The C-clamp  20  includes a conventional C-shaped member  22  preferably manufactured from cast iron or another hard metal alloy material. The C-shaped member  22  further includes a top section  24  and a bottom section  26  that are utilized with the other components of the present invention to appropriately retain a work piece (not shown) in the gap therebetween. The top section  24  in  FIG. 1  generally illustrates a cover  28  that houses the ratcheting mechanism used to move a threaded rod  30  axially as generally shown in  FIGS. 6-9 . The C-clamp  20  of the present invention further includes a handle  32  coupled to the ratcheting mechanism and retained in tension by a spring  34 . The spring  34  is preferably a tension spring. As will be described more fully herein, the rod  30  may be moved axially within the top section  24  of the C-shaped member  22  via the handle  32 , a lever  36  or a disengagement button  38  ( FIG. 2 ). 
       FIG. 2  illustrates the backside of the C-clamp  20  of the present invention. The handle  32  mounts to the C-shaped member  22  via a mount plate  40  ( FIGS. 1 and 2 ). The mount plate  40  is secured to the C-shaped member  22  via a pair of screws  42  and a pair of corresponding nuts  44 . The mount plate  40  may engage the C-shaped member  22  via any other method known in the art, including welding, other mechanical means, or adhesion. The mount plate  40  must be able to withstand the torque exerted at a handle pivot  46  when operating the handle  32  in accordance with the present invention. The cover  28  shields the corresponding backside of the ratchet mechanism as is shown in more detail in  FIG. 5 . 
       FIG. 3  illustrates an exploded view of the C-clamp  20  of the present invention additionally detailing the ratchet mechanism as shielded by the cover  28  in  FIG. 1 .  FIG. 3  illustrates the handle  32  removed from the C-shaped member  22 , the mount plate  40  and a ratchet body  48 . The handle  32  is secured to the mount plate  40  via a handle aperture  50  and a mount plate aperture  52 . A nut and bolt combination may be used to retain the handle  32  relative to the mount plate  40  about the handle aperture  50  and the mount plate aperture  52 . The important aspect is that the securement of the handle  32  relative to the mount plate  40  allows the handle  32  to rotate relative to the mount plate  40 , about the handle pivot  46  integral therein. The handle pivot  46  is concentric to the handle aperture  50  and the mount plate aperture  52 . 
     The handle  32  is retained in a tensioned position by the spring  34 . Preferably, the spring  34  is a tension spring or other material or mechanical device that is capable of maintaining the handle  32  in the position generally shown in  FIG. 4 . The spring  34  is attached to the handle  32  via a loop  54 . Loop  54  is preferably made from a similar hardened steel or other comparable material. The loop  54  may be welded to the handle  32  or formed integral therein from the same metal stock as the handle  32 . The loop  54  must be strong enough to withstand the axial forces exerted by the spring  34 . The spring  34  includes a top hook  56  that engages the loop  54  as generally shown in  FIG. 3 . A bottom hook  58  connects to a post  60  secured to the C-shaped member  22  by welding or the like. The bottom hook  58  is secured in a manner generally shown in  FIGS. 6-9 . The bottom hook  58  may also clip into the post  60 . Alternatively, the bottom hook  58  may attach to the C-shaped member  22  via a loop, similar to loop  54  and the top hook  56 . Although the spring  34  may attach to the C-shaped member  22  by any other method known in the art to retain a spring relative to movable members. In this regard, the spring  34  is pivotal to the movement of the handle  32  and the ratchet body  48  relative to the mount plate  40 . Preferably, the surface between the handle  32  and the mount plate  40  includes some form of grease or other lubricant to reduce any friction thereof. 
     The handle  32  is coupled to the ratchet mechanism via a ratchet aperture  62  and a corresponding slot  64  formed in the ratchet body  48 . A pin  66  ( FIG. 4 ) is retained concentrically within the ratchet aperture  62  and is configured to slide within the slot  64 . Movement of the pin  66  within the slot  64  is described in more detail below. It is the movement of the handle  32  engaged with the ratchet body  48 , relative to the C-shaped member  22  that provides one method of axial movement of the rod  30 . 
       FIG. 4  further illustrates the handle  32  coupled to the ratchet body  48  via the pin  66  in the slot  64 . Operation of the handle  32  generally involves squeezing the handle  32  toward the C-shaped member  22 , along the arrow shown in  FIG. 4 . The handle  32  is further tensioned by the spring  34  when moved along this directional arrow. Squeezing the handle  32  relative to the C-shaped member  22  is accomplishable with one hand. In effect, the handle  32  rotates about the handle pivot  46  thereby exerting a force on the pin  66  that causes the ratchet body  48  to rotate counter-clockwise. Such rotation causes the spring  34  to stretch. Thereby, the spring  34  exerts an axial force on the loop  54  that would otherwise cause the handle  32  to return to the position as shown in  FIG. 4 , absent the squeezing force exerted by a user.  FIG. 5  illustrates a backside view of the C-shaped member  22  wherein the ratchet mechanism includes a set of gear teeth  68  that engage a set of threads  70  integral to the rod  30 . Engagement of the gear teeth  68  with the threads  70  provides two methods for moving the rod  30  axially, as generally shown in  FIGS. 6-9 . 
       FIGS. 6-9  illustrate axial movement of the rod  30  within the top section  24  of the C-shaped member  22 .  FIGS. 6 and 7  illustrate descending movement of the rod  30 , while  FIGS. 8 and 9  illustrate ascending movement of the rod  30 . In  FIG. 6 , a pawl arm  72  is moved upwardly to engage a pawl  74  with any one of a set of ratchet teeth  76  ( FIG. 10 ). The pawl arm  72  is generally accessible for fingertip engagement through the cover  28  as shown in  FIG. 1 . In the position shown in  FIGS. 6 and 10 , the pawl arm  72  is coupled to the pawl  74  that engages the ratchet teeth  76  with abutting surfaces. As the handle  32  moves from the phantom position (to a compressed position) in  FIG. 7 , the engagement of the pawl  74  with the ratchet teeth  76  rotates the ratchet mechanism clockwise, as the arrow generally shows in  FIGS. 10-11 . The ratchet body  48  then slips back into position relative to a gear coupler  78  ( FIG. 15 ), as is more fully described below. The gear coupler  78  includes the gear teeth  68  and a block coupler  80 . The block coupler  80  is preferably shaped as some form of polygon. As best shown in  FIG. 15 , the block coupler  80  is coupled to the ratchet mechanism via a ratchet coupler  82 . As shown best in the top views of  FIGS. 10-11 , the block coupler  80  fits snugly within the indentations of the ratchet coupler  82 . Accordingly, the block coupler  80  could be any form of polygon that matches the indentations formed as part of the ratchet coupler  82 . In the embodiment shown in  FIGS. 10-13 , the block coupler  80  includes fewer sides than the corresponding indentations of the ratchet coupler  82 . The block coupler  80  may include a set of sides that correspond to the number of indentations in the ratchet coupler  82 . The block coupler  80  should not have more sides. The important aspect of this coupling is that as the handle  32  moves from an initial position to a compressed position, the pawl arm  72  engages the ratchet teeth  76  which, in turn, rotates the ratchet coupler  82  as engaged with the block coupler  80 . The block coupler  80  is then rotated as generally shown from  FIG. 10  to  FIG. 11 . Accordingly, the gear teeth  68  rotate as the block coupler  80  rotates. Rotation of the gear teeth  68  also causes rotation of the threads  70  of the threaded rod  30  as the gear teeth  68  are coupled thereto. Rotation of the threads  70  causes the rod  30  to either move upward or downward depending on the movement of the threading coupled thereto. The rotation of the gear coupler  78  as noted in  FIGS. 10-11  causes the corresponding engaged threads  70  to rotate the rod  30  downwardly. Hence, as the handle  32  in  FIG. 7  is pushed inwardly, as noted by the directional arrow, the corresponding rod  30  descends in the gap formed between the top section  24  and the bottom section  26  of the C-shaped member  22 . 
     Alternatively, the bidirectional ratcheting mechanism of the present invention allows an operator to ascend the rod  30  from within the gap formed between the top section  24  and the bottom section  26  of the C-shaped member  22 . Like the descending operation, ascending operation of the C-clamp  20  of the present invention is also feasible one-handed. As shown in  FIG. 8 , the pawl arm  72  is rotated downwardly as noted by the directional arrow. Accordingly, the pawl  74  engages the ratchet teeth  76  as shown in  FIGS. 12-13 , and opposite  FIGS. 10-11 . As depicted in  FIGS. 10-13 , the pawl  74  has a pair of teeth having a set of sloped inner edges  84  and a set of blocked outer edges  86  (best shown in  FIG. 15 ). In the embodiment of  FIG. 12 , the handle  32  is initially compressed or squeezed against the C-shaped member  22  by the user. Rotation of the pawl  74  according to the previously described motion, allows the sloped inner edges  84  to slip over the ratchet teeth  76 . Accordingly, the ratchet coupler  82  and corresponding gear coupler  78  do not rotate. Release of the handle  32 , as generally shown by the directional arrow in  FIG. 9 , rotates the handle  32  about the handle pivot  46  such that the pin  66  slides through the slot  64  allowing the ratchet body  48  and the handle  32  to return to the initial position shown in  FIG. 1 . As more specifically shown in  FIG. 13 , the outer edge  86  of the pawl  74  abuts a corresponding ratchet tooth  76  such that rotation of the ratchet body  48  causes counter-clockwise movement of the ratchet coupler  82 , the engaged block coupler  80  and the corresponding gear teeth  68 . Engagement of the gear teeth  68  with the threads  70  causes the rod  30  to ascend from within the gap formed between the top section  24  and the bottom section  26 , as generally shown by the arrow in  FIG. 13 . 
     The slipping of the pawl  74  relative to the ratchet teeth  76  also occurs when moving the rod  30  in the descending motion described in the embodiments of  FIGS. 6-7  and corresponding  FIGS. 10-11 . As specifically shown in  FIG. 10 , the outer edge  86  of the pawl  74  abuts a corresponding ratchet tooth  76 . The handle  32  is in the initial position of  FIG. 10 , as shown generally in  FIG. 6 . When the handle  32  is compressed, as shown from phantom in  FIG. 7 , the outer edge  86  of the pawl  74  remains abutted against the corresponding ratchet tooth  76 . The ratchet body  48  and the gear coupler  78  rotate as previously described. Return of the handle  32  to the initial position in  FIG. 6  allows the inner edge  84  to slip over the corresponding ratchet teeth  76 . Accordingly, no rotation of the ratchet body  48  or gear coupler  78  occurs. 
       FIGS. 14-15  show an exploded perspective view of the ratchet body  48  and corresponding gear coupler  78 .  FIG. 14  illustrates the ratchet body  48  having the slot  66  formed at one end therein. The pawl arm  72  is coupled to the pawl  74  by key fit. In this embodiment, the pawl arm  72  and pawl  74  have key fitting square structures formed therein. Although, it is conceived that this key fit may encompass any one of a number of different shapes, sizes or configurations. The important aspect is that as the pawl arm  72  is rotated either upwardly or downwardly, as previously described, the corresponding pawl  74  is also rotated within the ratchet body  48  (compare  FIGS. 10-11  with  FIGS. 12-13 ). 
     As shown in  FIG. 14 , the block coupler  80  fits snuggly into the ratchet coupler  82 . The ratchet coupler  82  has a plurality of ratchet teeth  76  disposed circumferentially around the exterior (best shown in  FIG. 15 ) thereof for engagement with the pawl  74 . The ratchet teeth  76  are generally hidden by the casing of the ratchet body  48 . The gear coupler  78  is retained within the C-shaped member  22  via the concentrically located bolt  88 , washer  89 , and corresponding screws  90  (also shown in  FIGS. 1-2 ). The screws  90  mount to the cover  28  as shown in  FIGS. 1-2  and may be optionally used with corresponding washers (not shown). 
     Pawl  74  is also disengageable from the ratchet teeth  76  via the disengagement button  38 .  FIGS. 16-17  illustrate an end view of the C-clamp  20 , and more specifically the ratchet body  48 . The disengagement button  38  is depressed from an initial engaged position ( FIG. 16 ) to a secondary disengaged position ( FIG. 17 ). The pawl  74  is disengaged from the ratchet teeth  76  by depressing the disengagement button  38  along the arrow generally shown in  FIG. 17 . A button spring  92  (also shown in  FIG. 15 ) is compressed against the corresponding pawl arm  72 . The disengagement button  38  protrudes from the exterior of the cover  28  via an aperture therein (not shown). The disengagement button  38  is biased outwardly to protrude through the exterior of the cover  28  via the button spring  92 . Depression of the disengagement button  38  causes the button spring  92  to be compressed against the pawl  74 . Disengagement thereof of the pawl  74  from the ratchet teeth  76  allows the rod  30  to freely move axially within the top section  24  of the C-shaped member  22 . The threads  70  of the rod  30  remain engaged with the gear teeth  68  of the gear coupler  78 . Axial movement of the rod  30  accordingly causes rotation of the gear teeth  68 , the corresponding block coupler  80 , the ratchet coupler  82 , and the ratchet teeth  76 . The difference in this embodiment is that the ratchet teeth  76  do not engage or slip against the now disengaged pawl  74 . Hence, the rod  30  may freely move axially within the top section  24  while the disengagement button  38  remains depressed. The rod  30  may ascend or descend within the gap formed between the top section  24  or the bottom section  26 . Such disengagement of the pawl  74  from the ratchet teeth  76  allows for faster axial movement of the rod  30 . Hence, the rod  30  is not limited to movement by the aforementioned ratcheting mechanism  48  or the pitch depth of the threads  70  of the rod  30 , as screwingly threaded via the lever  36 . 
     Moreover, the rod  30  may be tightened against a work piece, or correspondingly released from a work piece, by rotating the lever  36  ( FIGS. 1-2 ) either clockwise or counter-clockwise. Clockwise rotation rotates the threads  70  through the corresponding gear teeth  68  in order to descend the rod  30  through the top section  24 . The lever  36  is capable of supplying an additional 150 lbs. of hand pressure as a supplemental securement mechanism. The lever  36  provides a higher mechanical advantage relative to the handle  32  and corresponding ratchet mechanism. Such additional pressure further enables securement of a work piece within the gap formed in the C-shaped member  22 . Oppositely, counter-clockwise rotation of the threads  70  causes the rod  30  to ascend in the top section  24  via threading engagement with the gear teeth  68  of the gear coupler  78 . Such movement is independent of the ratchet mechanism or the disengagement button  38  as previously described. Rotation depth and speed is limited to the pitch depth of the threads  70  formed on the threaded rod  30 . 
       FIGS. 18-19  illustrate an enlarged plunger  94 , generally shown in  FIG. 3 . The plunger  94  is mounted to one end of the rod  30  and incorporates a kickback spring  96 . The spring  96  is located concentrically within the plunger  94  by slipping over the pair of location blocks  98 . The spring  96  is in an initial position in  FIG. 18 . Preferably the spring  96  is a 100 lb. spring that absorbs pressure and backlash when the plunger  94  is securely depressed against a work piece  100 , as generally shown in  FIG. 19 . The axial travel distance of the spring  96  is preferably limited to approximately 0.0030 of an inch. Once the rod  30  no longer retains the work piece  100  within the C-shaped member  22 , the spring  96  returns to the initial position as shown in  FIG. 18 . 
     One advantage of the present invention is the C-clamp  20  is configured for one-handed operation. A user is able to operate the C-clamp  20  by gripping the handle  32  and corresponding C-shaped member  22  with one hand. The spring  34  is tensioned such that the user may easily squeeze the handle  32  toward the C-shaped member  22  as previously described. Accordingly, the user may position a work piece or a plurality of work pieces within the gap formed between the top section  24  and the bottom section  26  of the C-shaped member  22  for securement within in the C-clamp  20 . Users are able to both tighten and loosen the work piece via the one-handed operation detailed above. 
     Although several embodiments have been disclosed in detail for purposes of illustration, various modifications may be made without departing from the scope and spirit of the invention.