Patent Publication Number: US-2022234172-A1

Title: High leverage locking pliers

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates generally to locking-type pliers, and more particularly to locking-type pliers adapted to apply a clamping force to an object. 
     BACKGROUND OF THE INVENTION 
     Locking pliers are an adjustable hand tool often used to grip a work piece, typically when other gripping methods have failed, such as on rounded fasteners, studs, or round shafts. The pliers generally include jaws that can be adjusted by a threaded screw mechanism to increase or decrease a gap between the jaws based on the size of the work piece or material being gripped by the locking pliers. For example, a locking-type pliers can include a screw mechanism on an upper handle of the pliers that, when rotated, pushes on a center link connected to one of the jaws to raise or lower the jaw, relative to the other jaw. 
     Locking pliers are also able to lock by moving the lower handle towards the upper handle until it “locks” due to, for example, an interaction between a release lever adjacent the lower handle and a center link connecting the upper handle to the lower handle. To release the locking feature, a release lever can then be lifted away from the lower handle to pry the lower handle away from the center link. 
     However, often it is difficult for a user to apply enough force to the handles of the pliers to lock the pliers and clamp the jaws of the pliers on the work piece. Further, in some cases, the user may not be able to apply enough force to the handles to create the desired jaw clamping force. An insufficient clamping force renders the gripping of the pliers on the work piece ineffective, and the jaws of the pliers can slip off of the work piece when the user attempts to manipulate the pliers. 
     SUMMARY OF THE INVENTION 
     The present invention relates broadly to high leverage locking-type pliers. The pliers incorporate a four bar linkage system adapted to amplify force applied by a user to an object gripped between jaws of the pliers. The linkage system also includes an over-center lock adapted to keep or lock the jaws closed with no additional force from the user. For example, the pliers may include first and second handles, first and second jaws, and a center link rotatably or pivotally coupled to the first and second handles. 
     A first link pivot where a center link pivotally couples to the second handle may be a first distance L1 away from a second jaw pivot where the second jaw pivotally couples the second handle. Additionally, a first jaw pivot where the second jaw pivotally couples the first handle is disposed a second distance L2 away from the second jaw pivot. In this embodiment, the first distance L1 is about 34% to about 70% of the second distance L2, and preferably about 43.5% of the second distance L2. This results in an increased clamping force with all jaw types common on locking pliers, and a low user force required to lock the pliers (such as, a clamping force about 25 times greater than a user force). 
     In an embodiment, the present invention relates broadly to a tool having first and second handles and first and second jaws. The second jaw is coupled to the first handle at a first jaw pivot, and coupled to the second handle at a second jaw pivot. A center link is coupled to the first handle at a slideable pivot and coupled to the second handle at a link pivot. A first distance between the second jaw pivot and the link pivot is about 34% to about 70% of a second distance between the second jaw pivot and the first jaw pivot. 
     In another embodiment, the present invention relates broadly to a tool having first and second handles, and a jaw coupled to the first handle at a first jaw pivot, and coupled to the second handle at a second jaw pivot. A center link is coupled to the first handle at a slideable pivot and coupled to the second handle at a link pivot. A first distance between the second jaw pivot and the link pivot is about 34% to about 70% of a second distance between the second jaw pivot and the first jaw pivot. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For the purpose of facilitating an understanding of the subject matter sought to be protected, there is illustrated in the accompanying drawing embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages, should be readily understood and appreciated. 
         FIG. 1  is side view of exemplar pliers, according to an embodiment of the present invention. 
         FIG. 2  is side view of one handle and jaw of exemplar pliers, according to an embodiment of the present invention. 
         FIG. 3  is side view of one handle and jaw of exemplar pliers, according to an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiments in many different forms, there is shown in the drawings, and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to embodiments illustrated. As used herein, the term “present invention” is not intended to limit the scope of the claimed invention and is instead a term used to discuss exemplary embodiments of the invention for explanatory purposes only. 
     The present invention relates broadly to high leverage locking-type pliers. The pliers incorporate a four bar linkage system adapted to amplify force applied by a user to an object gripped between jaws of the pliers. The linkage system also includes an over-center lock adapted to keep or hold the jaws closed with no additional force from the user. For example, the pliers may include first and second handles, first and second jaws, and a center link pivotally coupled to the first and second handles. A first link pivot where the center link pivotally couples to the second handle may be a first distance L1 away from a second jaw pivot where the second jaw rotatably or pivotally couples the second handle. Additionally, a first jaw pivot where the second jaw pivotally couples the first handle is disposed a second distance L2 away from the second jaw pivot. In this embodiment, the first distance L1 is about 34% to about 70% of the second distance L2, and preferably about 43.5% of the second distance L2. This results in an increased clamping force with all jaw types common on locking-type pliers, and a low user force required to lock or clamp the pliers. 
     As shown in  FIG. 1 , a tool  100  such as locking-type pliers, includes a first handle  102  and a second handle  104  pivotally coupled to one another. First and second jaws  106 ,  108  are respectively coupled to the first and second handles  102 ,  104 . As shown, each of the first and second jaws  106 ,  108  can include teeth  110  or knurling adapted to better grip or “bite” a work piece or other object disposed between the jaws. However, each of the first and second jaws  106 ,  108  can be other types of jaws and include other features. For example, and without limitation, the first and second jaws  106 ,  108  can be substantially flat clamping jaws, edged cutting jaws, needle-nose pliers type jaws, curved jaws, etc. 
     The first and second handles  102 ,  104  and the first and second jaws  106 ,  108  couple together at various pivot points to facilitate the operation of the tool  100 . For example, the second jaw  108  can couple to the first handle  102  at a first jaw pivot  112  and can couple to the second handle  104  at a second jaw pivot  114 . The second jaw  108  can also couple to the first handle  102  via an elastic member that pulls the first and second handles  102 ,  104  open or closed depending on the position of the first and second handles  102 ,  104 . In an embodiment, the first handle  102  is fixedly coupled to the first jaw  106  and the second handle  104  is rotatably or pivotally coupled to the second jaw  108 . 
     The tool  100  also includes a center link  116  pivotally coupled to the second handle  104  at a first link pivot  118 , and pivotally and slidably coupled to the first handle  102  at a slideable pivot  120 . The center link  116  interacts with an adjusting threaded screw mechanism  122  operably coupled to the first handle  102  that is adapted to adjust a jaw gap between the first and second jaws  106 ,  108 . As shown, the adjusting screw  122  can include a head  124  on a first end and a contact surface  126  on a second end opposite the first end, with threads extending at least partially therebetween. 
     To adjust the jaw gap between the first and second jaws  106 ,  108 , a user can rotate the head  124  of the adjusting screw mechanism  122  in a desired rotational direction and move the adjusting screw  122  axially inwardly or outwardly relative to a longitudinal axis of the first handle  102 , based on the functionality of the threads. For example, for right handed threads, the user can rotate the head  124  of the adjusting screw mechanism  122  clockwise to thereby push the surface  126  of the adjusting screw mechanism  122  against a face  128  of the center link  116 . In so doing, the center link  116  will push the second jaw  108  in a closing action towards the first jaw  106  at the second jaw pivot  114 , and thereby decreasing the jaw gap between the first and second jaws  106 ,  108 . Alternately, the user can rotate the head  124  of the adjusting screw mechanism  122  counterclockwise to increase the jaw gap between the first and second jaws  106 ,  108 , by pulling at the second jaw pivot  114  in a manner opposite that described above. 
     In some embodiments, the tool  100  can lock or clamp in manner that fixes the jaw gap between the first and second jaws  106 ,  108 , thereby clamping onto a work piece disposed between the first and second jaws  106 ,  108 . To lock or clamp the tool  100 , the second handle  104  is moved in a direction towards the first handle  102 . A clamping force on the second jaw  108  is transmitted about pivot  112  and can be modeled as an imaginary line (referred to as the “power line”) from pivot  114  to a contact point  130  between the surface  126  and face  128 . The tool  100  is locked or clamped when the second handle  104  is moved towards the first handle  102 , but is prevented from moving further toward first handle  102  by interaction of protrusion  134  of the center link  116  and abutment  136  of release lever  132 . As illustrated, the release lever  132  is coupled to the second handle  104  at release pivot  138 . 
     To release the locking function, the tool  100  includes a reverse link  132  that can be moved away from the second handle  104  and thereby push against the center link  116 . As shown, the center link  116  can include the protrusion  134  and the release lever  132  can include an abutment  136  that contact one another to prevent further closing of the first and second handles  102 ,  104  with respect to one another. The abutment  136  can further act as a first contact point during the releasing operation, when the user moves the release lever  132  at a tab  140  on the end of the release lever  132 . Here, the abutment  136  can contact the protrusion  134  and pry the second handle  104  away from the center link  116  and/or first handle  102 . 
     The tool  100  can also include an over-center locking feature, where the center link  116  can also include a protrusion that interacts with a release link. For example, such as the over-center locking feature described in U.S. Patent Application Publication No. 2020/0384613, titled Locking Pliers Release Mechanism, which is commonly owned with the present invention. 
     However, in prior designs, it can be difficult for a user to apply enough force to the handles of the pliers to lock the pliers and clamp the jaws of the pliers on a work piece. The present invention addresses this issue by disposing or placing the first link pivot  118  (where the center link  116  rotatably or pivotally couples to the second handle  104 ) a first distance L1 away from the second jaw pivot  114  (where the second jaw  108  rotatably or pivotally couples the second handle  104 ). Additionally, the first jaw pivot  112  (where the second jaw  108  rotatably or pivotally couples the first handle  102 ) is disposed or placed a second distance L2 away from the second jaw pivot  114 . 
     In an embodiment, the first distance L1 is about 34% to about 70% of the second distance L2, and preferably about 43.5% of the second distance L2. Additionally, a first line extending through the second jaw pivot  114  and first link pivot  118 , and a second line extending through the first link pivot  118  and contact point  130  are disposed apart by an angle α. In an example, the second distance L2 is about 1.465 inches, the first distance L1 is about 0.5 inches to about 1.0 inch, and preferably about 0.637 inches, and the angle α is about 171° to about 172°. This results in an increased clamping force with all jaw types common on locking-type pliers, and a lower user input force required to lock or clamp the pliers (clamp the first and second jaws), compared to prior designs. For example, in an embodiment, an input force of about 21.1 lbs. is required by a user to cause clamping or locking of the first and second jaws pliers, and the first and second jaws provide a clamping force of about 528.8 lbs. This results in a 25.1 mechanical advantage (i.e., the clamping force is about 25 times greater than the input force). The 25.1 mechanical advantage is greater than that provided by conventional designs. 
     For example, a first distance L1 that is about 107-108% of the second distance L2 requires an input force of about 60.1 lbs. by the user to cause clamping or locking of the first and second jaws pliers, and the first and second jaws provide a clamping force of about 460.7 lbs., resulting in a 7.7 mechanical advantage. In another example, a first distance L1 that is about 83% of the second distance L2 requires an input force of about 39.3 lbs. by the user to cause clamping or locking of the first and second jaws pliers, and the first and second jaws provide a clamping force of about 488.5 lbs., resulting in a 12.4 mechanical advantage. 
     As mentioned above, the first and second jaws  106 ,  108  can be other types of jaws and include other features. Referring to  FIG. 2 , a second half of another embodiment of exemplar pliers is shown, and may include a second jaw  208  that includes a cutting surface. Similar to the exemplar pliers  100  described above, the second half of the pliers includes a second handle  204  and second jaw  208 . The second jaw  208  can couple to a first handle at a first jaw pivot  212  and can couple to the second handle  204  at a second jaw pivot  214 . In an embodiment, the second handle  204  is pivotally coupled to the second jaw  208 . A center link  216  is also pivotally coupled to the second handle  204  at a first link pivot  218 , and pivotally and slidably coupled to the first handle at a slideable pivot. The center link  216  interacts with an adjusting screw mechanism  222  operably coupled to the first handle to adjust a jaw gap. As shown, the adjusting screw mechanism  222  can include a head  224  on a first end and a contact surface  226  on a second end opposite the first end, with threads extending at least partially therebetween. The surface  226  of the adjusting screw mechanism  222  abuts a face  228  of the center link  216  at a contact point  230 . 
     Referring to  FIG. 3 , a second half of another embodiment of exemplar pliers is shown, and may include a second jaw  308  that includes a substantially flat surface. Similar to the exemplar pliers  100  described above, the second half of the pliers includes a second handle  304  and second jaw  308 . The second jaw  308  can couple to a first handle at a first jaw pivot  312  and can couple to the second handle  304  at a second jaw pivot  314 . In an embodiment, the second handle  304  is pivotally coupled to the second jaw  308 . A center link  316  is also pivotally coupled to the second handle  304  at a first link pivot  318 , and pivotally and slidably coupled to the first handle at a slideable pivot. The center link  316  interacts with an adjusting screw mechanism  322  operably coupled to the first handle to adjust a jaw gap. As shown, the adjusting screw mechanism  322  can include a head  324  on a first end and a contact surface  326  on a second end opposite the first end, with threads extending at least partially therebetween. The surface  326  of the adjusting screw mechanism  322  abuts a face  328  of the center link  316  at a contact point  330 . 
     Similar to the exemplar pliers  100 , the first link pivot  218 / 318  (where the center link  216 / 316  rotatably or pivotally couples to the second handle  204 / 304 ) is a first distance L1 away from the second jaw pivot  214 / 314  (where the second jaw  208 / 308  rotatably or pivotally couples the second handle  204 / 304 ). Additionally, the first jaw pivot  212 / 312  (where the second jaw  208 / 308  rotatably or pivotally couples the first handle) is disposed a second distance L2 away from the second jaw pivot  214 / 314 . 
     In an embodiment, the first distance L1 is about 34% to about 70% of the second distance L2, and preferably about 43.5% of the second distance L2. Additionally, a first line extending through the second jaw pivot  214 / 314  and first link pivot  218 / 318 , and a second line extending through the first link pivot  218 / 318  and contact point  230 / 330  are disposed apart by an angle α. In an example, the second distance L2 is about 1.465 inches, the first distance L1 is about 0.5 inches to about 1.0 inch, and more particularly about 0.637 inches, and the angle α is about 171° to about 172°. This results in an increased clamping force with all jaw types common on locking-type pliers, and a low user force required to lock the pliers compared to prior designs. 
     As used herein, the term “coupled” and its functional equivalents are not intended to necessarily be limited to direct, mechanical coupling of two or more components. Instead, the term “coupled” and its functional equivalents are intended to mean any direct or indirect mechanical, electrical, or chemical connection between two or more objects, features, work pieces, and/or environmental matter. “Coupled” is also intended to mean, in some examples, one object being integral with another object. As used herein, the term “a” or “one” may include one or more items unless specifically stated otherwise. 
     The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of the inventors&#39; contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.