Patent Publication Number: US-8984993-B1

Title: One handed locking pliers

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to hand tools and more specifically to a one handed locking pliers, which requires less effort to operate than that of the prior art. 
     2. Discussion of the Prior Art 
     U.S. Pat. No. 5,056,385 to Petersen discloses a compound toggle link. U.S. Pat. No. 6,095,019 to Warheit et al. discloses a locking pliers tool. U.S. Pat. No. 7,762,162 to Phillips, Sr. et al. discloses a locking pliers with cam. 
     Accordingly, there is a clearly felt need in the art for a one handed locking pliers, which requires less effort to operate than that of the prior art. 
     SUMMARY OF THE INVENTION 
     The present invention provides a one handed locking pliers, which requires less effort to operate than that of the prior art. The one handed locking pliers (locking pliers) preferably includes a fixed jaw, a movable jaw, a fixed handle, an adjusting screw, a toggle link, a power link, a biasing device and a movable handle. The phrase, “one handed” means that the locking pliers is operable with a single hand, which allows the other hand to manipulate an object to be clamped in the jaws of the locking pliers. The fixed jaw, the movable jaw, the fixed handle, the adjusting screw and the biasing spring are preferably taken from an Irwin item no. 502L3 vise grips, but other parts may also be used. U.S. Pat. No. 5,056,385 is hereby incorporated into this patent application by reference in its entirety. The fixed jaw is retained in one end of the fixed handle and the adjusting screw is threadably retained in an opposing end of the fixed handle. The movable jaw is pivotally retained in the one end of the fixed handle. 
     The toggle link includes a first leg, a second leg and a cross member. A first end of the first and second legs is attached to each other and a second end of the first and second legs are separated from each other to receive a thickness of the power link. The toggle link preferably has a substantial “Y” configuration. A screw notch is formed in the first end of the first and second legs to receive an end of the adjustment screw. The cross member is attached to a top of the first and second legs at substantially a middle thereof. A toggle pivot hole is formed through the second end of the first and second legs to pivotally engage the power link. The power link includes a first end and a second end. A toggle pivot hole is formed through the first end of the power link. A handle pivot hole is formed through substantially a second end of the power link. A centerline projection extends downward from a bottom of the power link. The centerline projection contacts an inner surface of the movable handle and forces a pivot point of the power link and the moveable handle to go slightly above a power centerline drawn through a center of a jaw pin and a link pin. A release stop extends from a top of the power link, adjacent the handle pivot hole. 
     The movable handle includes a handle portion and an actuation portion. The handle portion includes a first end, a second end and a U-shaped cross section. A first end of the actuation portion extends from a first end of the handle portion. The actuation portion includes a first actuation leg, a second actuation leg and a handle cross member. The first actuation leg extends from a first side of the handle portion and the second actuation leg extends from a second side of the handle portion. The handle cross member connects a top of the first and second actuation legs together. A jaw hole is formed through a second end of the actuation portion. A power hole is formed a first end of the actuation portion. 
     The centerline biasing device includes a pair of pivot links, a spring plunger and a compression spring. A first end of the pair of pivot links is pivotally secured to the first end of the power link. A second end of the pair of pivot links is pivotally secured to the spring plunger. The compression spring is axially retained on the spring plunger. A spring pocket is preferably created in the second end of the handle by attaching a J-shaped cover plate thereto. The compression spring and the spring plunger are retained in the spring pocket. 
     A jaw pin is retained in the jaw hole in the actuation portion and the movable jaw. A power pin is retained in the power hole of the actuation portion and the handle pivot hole of the power link. A toggle pin is retained in the toggle pivot hole of the power link and the toggle pivot hole of the toggle link. In use, the clamp stop projection contacts an inside surface of the movable handle and prevents an object from being clamped too far over the power centerline. The release stop of the power link contacts the handle cross member of the movable handle and prevents the moveable handle from dropping down too far from the fixed handle. 
     Accordingly, it is an object of the present invention to provide a locking pliers, which requires less effort to operate than that of the prior art. 
     These and additional objects, advantages, features and benefits of the present invention will become apparent from the following specification. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of a locking pliers in a closed orientation in accordance with the present invention. 
         FIG. 2  is a side view of a locking pliers in an open orientation in accordance with the present invention. 
         FIG. 3  is an exploded side view of a toggle link, a power link, a movable handle of a locking pliers in an open orientation in accordance with the present invention. 
         FIG. 4  is an exploded top view of a toggle link, a power link, a movable handle and a centerline biasing device of a locking pliers in accordance with the present invention. 
         FIG. 5  is an end view of a movable handle of a locking pliers in accordance with the present invention. 
         FIG. 6  is a bottom view of a locking pliers in a closed orientation in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference now to the drawings, and particularly to  FIG. 1 , there is shown a side view of a locking pliers  1  in a closed orientation. With reference to  FIGS. 2-3 , the locking pliers  1  preferably includes a fixed jaw  10 , a movable jaw  12 , a fixed handle  14 , an adjusting screw  16 , a biasing spring  18 , a toggle link  20 , a power link  22 , a centerline biasing device  24  and a movable handle  26 . The fixed jaw  10 , the movable jaw  12 , the fixed handle  14 , the adjusting screw  16  and the biasing spring  18  are preferably taken from an Irwin item no. 502L3 vise grips, but other parts may also be used. U.S. Pat. No. 5,056,385 is hereby incorporated into this patent application by reference in its entirety. The fixed jaw  10  is retained in one end of the fixed handle  14  and the adjusting screw is threadably retained in an opposing end of the fixed handle  14 . The movable jaw  12  is pivotally retained in the one end of the fixed handle  14  with a pivot pin  28 . One end of the biasing spring  18  is attached to the movable jaw  12  and the other end is attached to the fixed handle  14 . A knurled head  26  is preferably formed on an end of the adjusting screw  16 . The knurled head  27  is used to increase point pressure of the fixed and movable jaws  10 ,  12 . 
     With reference to  FIG. 4 , the toggle link  20  includes a first leg  30 , a second leg  32  and a cross member  34 . A first end of the first and second legs  30 ,  32  are preferably welded to each other and a second end of the first and second legs  30 ,  32  are separated from each other to receive a thickness of the power link  22 . The toggle link  20  preferably has a substantial “Y” configuration. A screw notch  36  is formed in the first end of the first and second legs  30 ,  32  to receive an end of the adjustment screw  16 . The cross member  34  is preferably welded to a top of the first and second legs  30 ,  32 . A toggle pivot hole  38  is formed through the second end of the first and second legs  30 ,  32  to pivotally engage the power link  22 . 
     The power link  22  includes a first end and a second end. A toggle pivot hole  40  is formed through the first end of the power link  22 . A handle pivot hole  42  is formed through substantially a second end of the power link  22 . A centerline projection  44  extends downward from a bottom of the power link  22 . The centerline projection  44  includes a rounded perimeter. With reference to  FIG. 1 , the centerline projection  44  contacts an inner surface of the movable handle  26  and forces a pivot point of the power link  22  and the moveable handle  26  to go slightly above a power centerline  46  drawn through a center of a link pin  48  and a jaw pin  50 . A power stop projection  52  extends from a top of the power link  22  and is formed adjacent the toggle pivot hole  40 . A handle stop projection  54  extends from a top of the power link and is formed adjacent the handle pivot hole  42 . A length of the power link  22  is greater than a length of the toggle link  20 . 
     With reference to  FIG. 5 , the moveable handle  26  includes a handle portion  56  and an actuation portion  58 . The handle portion  56  includes a first end and a second end. The handle portion  56  also includes a U-shaped cross section. The U-shaped cross section includes a first handle leg  60 , a second handle leg  62  and a bottom portion  64 . The first handle leg  60  extends upward from a first end of the bottom portion  64  and the second handle leg  62  extends upward from a second end of the bottom portion  64 . A first end of the actuation portion  58  extends from a first end of the handle portion  56 . The actuation portion  56  includes a first actuation leg  66 , a second actuation leg  68  and a handle cross member (handle stop projection)  70 . The first actuation leg  66  extends from the first handle leg  60  and the second actuation leg  68  extends from the second handle leg  62 . The handle cross member  70  is preferably welded to a top of the first actuation leg  66  and the second actuation leg  68 . A jaw hole  72  is formed through a second end of the actuation portion  58 . A power hole  74  is formed through the actuation portion  58  at substantially a first end thereof, adjacent the handle cross member  70 . 
     The jaw pin  50  is retained in the jaw hole  72  in the actuation portion  58  and the movable jaw  12 . A power pin  78  is retained in the power hole  74  of the actuation portion  58  and the handle pivot hole  42  of the power link  22 . The toggle pin  48  is retained in the toggle pivot hole  40  of the power link  22  and the toggle pivot hole  38  of the toggle link  20 . 
     The centerline biasing device  24  includes a pair of pivot links  80 , a spring plunger  82  and a compression spring  84 . A first end of the pair of pivot links  80  is pivotally secured to the first end of the power link  22  with a first link pin  81 . A second end of the pair of pivot links  80  is pivotally secured to the spring plunger  82  with a second link pin  83 . The compression spring  84  is axially retained on the spring plunger  82 . The spring plunger  82  includes a stop flange  86 . A spring pocket  88  is created in the second end of the movable handle  26  by attaching a J-shaped cover plate  90  thereto. The compression spring  84  and the spring plunger  82  are retained in the spring pocket  88 . 
     In use, the clamp stop projection  44  contacts an inside surface  65  of the bottom portion  64  and prevents an object from being clamped too far over the power centerline  46 . With reference to  FIG. 2 , the cross member  34  of the toggle link  20  contacts the release stop  52  of the power link  22  and prevents the moveable handle  26  from dropping too far downward from the fixed handle  14 . The power stop projection  54  of the power link  22  contacts the handle cross member  70  of the movable handle  26  and also prevents the moveable handle  26  from dropping too far downward from the fixed handle  14 . 
     While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.