Abstract:
A tool useful for clamping, cutting, and the like comprising at least two force multiplying elements which act upon a gear reduction hub that moves a first jaw towards a second jaw. The tool applies greatly multiplied force to the jaws by repeatedly advancing the force multiplying elements in ratcheting manner. The force is maintained in a substantially continuous manner by a separate locking pawl that engages a geared face.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     This application claims the benefit of provisional application 62/081,376 which was filed on Nov. 18, 2014. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to the field of hand tools. 
     BACKGROUND OF THE INVENTION 
     Hand tools such as conventional pliers, bolt cutters, and cutting pliers are used for various tasks involving gripping, cutting, and clamping. Such tools typically consist of two levers that work in opposite directions with a fulcrum at the point where the levels rotate (i.e. both levers are first-class levers). The basic mechanical principle underlying such tools is that exerting force on the handles of a pair of pliers multiplies the force several times when it is exerted on the load. These basic are well adapted for common tasks and are in common use. However, there are applications in which it can be useful to multiply the force beyond the range made feasible by the simple levers associated with such tools. One such application is the cutting of a ring that has become too tight on a finger to be removed by slipping the ring off the finger. Rings are often too thick to permit cutting with simple lever-based tools. Likewise, the adoption of hard metals such as titanium, tungsten carbide, and platinum as materials for rings makes such rings very difficult to cut through. 
     Rings can become tight on a finger when an injury such as a fracture causes the adjacent tissue to swell. This can be very painful to the person wearing the ring and can restrict circulation, obstruct lymphatic drainage, and lead to additional swelling. There are various techniques for removing rings from injured fingers. In some cases, lubrication with soap and water is enough to permit twisting the ring off the finger. If the ring is too tight or the wearer is too much pain, a conventional ring cutter can be used to cut through a narrow ring band. Such cutters consist of a lever that slides a protective cutting plate under the ring while a miniature circular saw blade is lightly pressed onto the outer portion of the ring and rotated to saw through the ring band. Once the cut has been made, the ring may be bent apart and removed. Another technique is to use a high speed rotary tool with a sharp-edged grinder attachment in conjunction with a heat-resistant shield between the skin and ring. The increasing popularity of rings made from hard metals such a platinum and titanium, have made ring removal a more difficult task. For example, it can take several minutes to remove a ring made of platinum or titanium using a conventional ring cutter. Furthermore, rings made of tungsten carbide can be extremely difficult, if not impossible to cut. Such rings are typically removed by using locking pliers or a hammer to induce the ring to crack. Such methods lack precision and expose the person wearing the ring to further injury. Therefore, there is a need in the field for a tool that operates quickly and effectively to cut and remove rings of any type. 
     BACKGROUND OF THE INVENTION 
     The invention comprises a hand tool in the general configuration of pliers having gripping jaws or cutting edges. The invention can be used for gripping, clamping, or cutting objects. A critical feature of the tool is the use of force multipliers to transfer force from a hand lever to a gear reduction hub that is connected to one of the jaws. Force multipliers are devices that are able to provide greater output force than input force. Examples of force multipliers include levers, pulleys, screws, gears, and hydraulic pistons that are configured to increase output force. 
     For example, the preferred embodiment of the tool is a ratcheting cutter has force multipliers working together to produce sufficient torque to cut through any metal, including titanium. This kind of tool can readily be configured such that 52 lb-ft of torque at the handle will produce over 100,000 lb-ft of torque at the cutting head in a smooth and continuous progression of applied force. This cutting device can be used in a variety of fields, but is particularly suited for use as a ring cutter. In addition, such a tool can cut through fencing, pad locks, cable, and bolts. With a different head design, the tool can be used for gripping and clamping onto various surfaces. 
     The preferred embodiment of the tool is configured in the general form of a hand tool having a pair of handles of which the lower handle acts as a lever, being joined to a double fulcrum force multiplier that is connected to an engagement pawl. By applying force to the lower lever it substantially increases the force applied to a pawl, which in turn rotates a gear hub which acts as another force multiplier. By pushing a detentable button at top of tool, a slide will move down the back of cam release slide and cause a locking pawl to engage the hub. When the locking pawl is engaged, a spring in the pawl ejects the pawl from gears and allows the gear hub to rotate forward in a ratcheting manner as the handles are repeated squeezed together and released. This causes the upper jaw at the opposing end to advance towards the lower jaw in a controlled manner for clamping or cutting. When finished, the user may push the detentable button on the top of the tool to a different position, thus causing the slide to disengage the locking pawl from the gear hub, thus allowing the tool to return to a reset position. 
     The tool can also be made using other combinations of force multipliers to apply force to a gear reduction hub. For example, in another embodiment, the lower handle can be squeezed to drive a bar having a pawl at its end into the teeth of gear which in turn drives the gear reduction hub to rotate in a forward direction. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of one embodiment of hand tool. 
         FIG. 2  is a side view of another embodiment of the hand tool. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The preferred embodiment of the hand tool  1  is shown in  FIG. 1 . The tool  1  has a base member  2  that encompasses the upper handle and head portion of the tool  1 . A lower handle  3  has a distal end  5  that is attached to the base member  2  by a pin  6  and to a connecting lever  7  by another pin such that the lower handle pivots about pin  6 . The connecting lever  7  is attached to the base member  2  by a pin  23  such that the center of the connecting lever  7  pivots about pin  23 . The connecting lever is further attached by a pin  9  to an advancing pawl  10  that has a toothed face  21 . The assembly of the lower handle  3 , connecting lever  7 , and advancing pawl  10  form a double fulcrum thus creating a mechanical advantage that substantially multiplies the force applied to the pawl when the lower handle  3  is squeezed towards the upper handle of the base member  2 . 
     A gear reduction hub  11  is attached to the base assembly by a pin  18  about which it pivots. The gear reduction hub  11  has a geared face  22  with teeth that are configured to engage with the toothed face  21  of the advancing pawl. When the lower handle  3  is squeezed towards the upper handle of the base member  2 , the engagement of the advancing pawl with the geared face  21  creates an additional mechanical advantage causing the gear reduction hub  11  to pivot about pin  18  and thus moving the upper jaw  12  of the tool towards the lower jaw  13 . The amount of throw in the movement of the assembly of the lower handle  3 , connecting lever  7 , and advancing pawl  10  is fairly short, and thus a user will generally need to squeeze the lower handle  3  towards the upper handle  25  several times to cause the upper jaw  12  to move from a fully open position to a closed position in which the upper jaw touches the lower jaw  13 . 
     Retrocession of the gear reduction hub  11  during advancement is prevented by engagement of a locking pawl  14  with the geared face  22  of the gear reduction hub  11 . This ensures a continuous application of force by the upper jaw  12  as the tools clamps or cuts material. A compression slide  15  is pivotably attached to the locking pawl at one end and to a release button  17  at the other end, which fits over a slot  20  in the base member  2 . A spring  24  maintains a bias force on the locking pawl to keep it pressed against the gear face as the gear reduction hub  11  is advanced towards a closed position. 
     A bar  16  pivotally connects the middle of the compression slide  15  to a hole or slot  19  in the gear reduction hub  11 . By pushing the release button  17  forward, the compression slide forces the locking pawl  14  to engage the geared face. Pushing downward on the release button  17  forces the compression slide to push down on the base of the locking pawl  14 , thus causing it to disengage from the gear face  22 . The disengagement is made easier if the lower handle  3  is squeezed lightly while depressing the release button  17 . Pulling backward on the release button  17  causes the bar  16  to pull the gear reduction hub  11  to the open position and thus resets the upper jaw  12  to its starting position. 
     The tool  1  can be fitted with different kinds of jaws  12  and  13  depending on the intended function of the tool  1 . For example, as shown on  FIG. 1 , upper jaw  12  and lower jaw  13  are configured to enable the tool to be used as a clamp, crimping, or crushing device. The tool  1  can also be configured as a cutting device by fitting an upper jaw  116  and lower jaw  117  that have cutting edges. In addition, lower jaw  117  can be configured to act as an anvil which receives an upper jaw  116  having a cutting edge. This combination can be particularly useful when the tool  1  is used as a ring cutter, in which case the lower jaw  117  is best configured to have a thin profile, preferably 4 millimeters or less, that may be readily inserted between a finger and a ring. To use as an ring cutter, the tool  1  is opened and placed so that the lower jaw  117  is located between a finger and ring. The upper jaw  117  is manually advanced to make contact with object by squeezing the lower handle  3  causing the tool  1  to ratchet with amplified pressure to cut through the ring. If the band of ring is constructed of a material sufficiently thin and bendable, the ring can be removed by bending the ends of band outwards until the opening is wide enough to pass the ring off the finger. Otherwise, the tool  1  can be placed on the side of the ring opposite from the cut and making a second cut. Once the second cut is made, the ring can be removed from the finger by pulling off the two halves of the ring. 
     An alternate embodiment of the hand tool  101  is shown in  FIG. 2  in which a advancing bar  104  and advancing gear  109  replaces the double fulcrum mechanism shown in  FIG. 1 . In this embodiment, the lower handle  3  is attached to the base member  2  by a spring hinge  105  thus allowing the lower handle  3  to be squeezed towards the upper handle  107  of the base member  2  and returning to its original position by force exerted by the spring hinge  105 . Another spring hinge  106  in the middle portion of the lower handle  3  exerts a bias force on the advancing bar  104  causing it to engage the advancing gear  109  when the lower handle  3  is squeezed towards the upper handle  107  and allowing advancing bar  107  to slide back over the teeth of the advancing gear  109  as the lower handle  3  is returned to its original position. 
     A pin  108  pivotably attaches the gear reduction hub  111  to the base member  2 . The gear face  112  may extend past the bottom edge of the gear reduction hub  111  so that the gear reduction hub  111  does not interfere with the spring hinge  105 . The upper jaw  116  may be an integral part of the gear reduction hub  111  or may be selectively detachable by putting a attachment point (not shown) in the region  118  that will not interfere with the base assembly member. In general, it is preferred that an attachment point not be located in an the area  115  where the attachment point might so interfere. 
     The advancing gear  109  is engaged with the gear face  112  on the gear reduction hub  111 . When the lower handle  3  is squeezed towards the upper handle  107 , the advancing bar  104  engages the advancing gear  109  and exerts a mechanical advantage while gear face  113  of the advancing gear  109  simultaneously engages the gear face  112  of the gear reduction hub  111  thus causing the gear reduction hub  111  to pivot about pin  108  and causing the upper jaw  116  to move towards the lower jaw  117 . The radius length of the advancing gear  109  will determine both the extent of advancement of the gear reduction hub  111  when the lower handle  2  is squeezed as well as the magnitude of the mechanical advantage. A user will generally need to squeeze the lower handle  3  towards the upper handle  107  several times to cause the upper jaw  116  to move from an open position to a closed position in which the upper jaw touches the lower jaw  117 . 
     The gear reduction hub  111  is prevented from receding during advancement by engagement of a locking pawl  121  with the advancing gear  109 . The locking pawl  121  engages with the gear face  113  of the advancing gear  109 . The locking pawl  121  can be selectively released and engaged from the advancing gear  109  by pushing a release button  110  forward and backward in the slot  120  in the base assembly  2 . 
     Although the invention has been described with reference to a particular arrangement of parts, features, and the like, these are not intended to exhaust all possible arrangements or features, and indeed many other modifications and variations will be ascertainable to those of skill in the art.