Patent Publication Number: US-2020282523-A1

Title: Interchangeable Jaw Pliers

Description:
FIELD OF INVENTION 
     The invention relates to pliers with interchangeable jaws. 
     BACKGROUND TO THE INVENTION 
     Existing locking pliers disclosed by U.S. Pat. No. 9,855,642 (Wu), US2015273664 (Skodje et al) and U.S. Pat. No. 9,855,642 (Wu) comprise two handles connected to respective jaws, and a locking mechanism connected to the two jaws. The handles can be squeezed to close the jaws. A locking member is attached to an over centre linkage, which when utilized prevents the lower handle from pivoting from its closed configuration and until opened retains the jaws in a closed position. The clamping width of the jaws is adjusted by an adjustment screw. The adjustment screw also determines the clamping pressure exerted upon the clamped workpiece. As the clamping pressure has to be pre-set, it can take several attempts to correctly adjust the screw to the position required to clamp the workpiece the optimum way. The clamping width of the jaws once set by the adjusting screw is finite, so any movement, vibration or relaxing of the clamped material will normally result in the failure of the clamping action. This is most prevalent when the pliers are used to initially clamp vehicle bodywork parts during a panel beating process prior to welding or bolting the panels as inadvertent over pressure applied by the clamping jaws usually results in damage or distortion of the clamped parts. 
     USD742194 (Engel et al) shows pliers having a toothed strut with a locking mechanism attached to one operating arm. As the arms are closed, the teeth ratchet past the lock. As the operating arms are not designed to resiliently deform, the toothed arc of the strut remains in substantially the same locking angle relative to the locking mechanism. 
     EP2818280(Buchanan) discloses pliers having a bowed or arcuate portion to permit limited flexing of one of the handles. A pivotal strut is retained between the handles. A first end of the strut is slidably held in a channel within one handle and the second end is pivotally held within the other handle. The second end has an arcuate side surface provided with teeth of the strut. The strut acts with a switch and a pawl to lock or unlock the handle positions relative to one another. The compression of the handles closing the gap between the fixed and moveable jaws, the moveable jaw sliding up a clamp bar portion until the jaws robustly contact the workpiece, the further operation of the handles resulting in the clamping of the workpiece, the resilient arcuate portion acting to impose a limited sprung grip upon the workpiece, further usefulness imported by the locking action of the pawl teeth within the strut arc teeth when the pawl is switched into its ratchet locking position retaining the handles substantially in their closed position providing a limited spring grip upon the workpiece. The arc of the toothed strut in conjunction with the corresponding toothed arc of the pawl being capable of compensating for the changes in angles of one handle relative to the other as the resilient portion flexes as differing pressures are applied to the handles during use, the pawl is activated into either a locking or non-locking position by a further separate “rocker” switch incorporating a spring and plunger mechanism which acts upon the pawl. 
     It is an object of the present invention to at least partially alleviate the above-mentioned disadvantages, or to provide a cost saving alternative to existing products. 
     SUMMARY OF THE INVENTION 
     The invention provides interchangeable jaw pliers as specified in claim  1 . 
     Examples of the invention interchangeable jaw pliers comprising a head portion incorporating gripping faces within the opposing jaws for the clamping of the desired workpiece, pivotal handle portions and a pivotal strut positioned between the handles. Bow shaped resilient portion or portions can be usefully incorporated within either or both the jaw or handle portions, when the pliers are operated these resilient portions impart a useful sprung pressure upon the clamped workpiece by the gripping face of the jaws. The jaws can be usefully locked in the required clamping position upon the workpiece, in this example by a pivotal strut having a first end toothed arc being locked or unlocked according to the toothed switch operation within the first handle and having a strut second end slidingly engaged within a strut channel in the opposing second handle by an axle pin. The said opposing or second handle having a recess or channel with outer slots for the retention of the strut second end axle pin within the said slots, the strut second end is driven down the second handle channel within the confines of the slots as the handles are closed relative to one another, the pivoting first end of the strut the toothed arc, ratcheting against the sprung biased corresponding switch teeth. In order to provide as versatile as possible a set of pliers the jaw portions are interchangeable with other jaw portions the gripping faces can comprise of clamping or gripping profiles useful for many purposes, metalwork, woodwork and automotive to name but a few, whilst the handle portion within its particular size range can be the same incurring a substantial cost and storage saving. 
     The interchangeable jaw pliers may comprise an intuitive switch locking/unlocking mechanism utilizing less parts than previous pliers type tools comprising pivotal struts with toothed arcs interacting with a switch. The switch usefully now directly incorporates a single piece locking, ratcheting or disengaged teeth mechanism according to its chosen orientation, which can be usefully utilized as required to engage with the teeth of the toothed strut arc to positionally to lock as required the same, thereby locking the clamped workpiece within the jaw portions, or alternately disengaging the switch teeth from the strut toothed arc releasing the workpiece from the jaws, according to the pivotal switch orientation. 
     The switch may incorporate a ratchet function, the switch usefully incorporating a bore for the engagement of a biasing pin and its compression spring, said biasing pin being free to move lengthwise within said bore against the resilient force of the spring. In best practice the outer end of the biasing pin is rounded or angled with a blunt point for ease of movement against a corresponding peaked engagement profile. Said pin having a close sliding fit within said bore whereas it can easily traverse inwards or outwards against the spring within said bore according to the engagement between the blunt point and the corresponding peaked engagement profile mounted within the handle. Said switch engagement profile further comprising of a transition peak with a sloping open profile on one side and a switch closing profile on the other, the pivotal switch can be manually intuitively operated by the operator from either chosen position, during said switch positional operation said biasing pin is resiliently propelled into the switch bore against the incumbent spring as its outward blunt point moves against the corresponding upwardly sloping engagement profile till it traverses the peak of the engagement profile and consequently now engages the downwardly sloping engagement profile at the other side of the peak, the switch spring usefully resiliently propelling the biasing pin blunt outward end against its corresponding sloping engagement profile positively resiliently engaging or disengaging the switch teeth from the toothed strut arc teeth according to the operators requirements. 
     As it is commercially prudent to have a ratchet like clicking noise to accompany the jaw closure and locking procedure the interaction of the resiliently biased switch teeth with the corresponding pivotal strut toothed arc teeth, when the switch is in the closed position provides a typical ratchet like sound as the strut rotates during the closure procedure around the strut axle against the resilience of the strut spring. 
     The interchangeable jaw pliers may provide clamping widths within its specification that are automatically adjusted, the locking pressure can be further be usefully determined by the operator by the straightforward gripping pressure of the handles, the simple release of the handles when the switch is in the closed position initiating the locking if required of the jaws upon the clamped parts. The operator defining the option of the device being in the locking or unlocked mode by the positioning of said switch. The clamping action of said jaws being determined by the remaining resilience of the bowed portions, the elastic potential energy. The resultant jaw resilient closing force is largely proportional to the force applied to the handles and the pivotal dimension ratio between the handles and jaws less any small losses incurred during the switch locking procedure, the fulcrum being the jaw pivot pin. 
     The invention also includes, in a further iteration in order to provide a more versatile and useful device, a method whereby the jaw working profiles or outer jaw can be interchanged with other outer jaws with differing working profiles in order to provide a cost-effective equivalent to several set of differing pliers required for different jobs. These interchangeable jaws being usefully locked or unlocked from robust engagement within the lower jaws as required, providing one locking handle set capable of use with a cost-effective range of differing jaws as required. 
     In one example the lower jaws comprising of a laminate like construction in order to provide a low-cost method of retaining the locking swivel pin which comprises a central axle rotatable within a corresponding thickness and bore within the lower jaw inner plate. The locking swivel pin having a further reduced circumference hereafter termed outer axles, largely level in height to the lower jaw outer plates which have corresponding circular cut out profiles such that the said swivel pin is laterally held within the lower jaw by the outer plates whilst capable of rotation within its afforded enclave. The outer end face of the locking swivel pin can usefully incorporate a small lever for the required operator rotation of the said pin. The locking swivel pin outer axles comprising a spherical locking face and a generally flat unlocking face, the spherical locking face can be further appropriately cam shaped in order to increase the locking mechanism proficiency. The locking swivel pin is located partially within the lower jaw interlocking tongue recess, by rotating the locking swivel pin the profile of the locking swivel pin outer axle can be chosen to either present a locking or unlocking face into the tongue recess. The detachable outer jaws having corresponding locking tongues incorporated within their generally planar outer plates, in best practice the tongues are formed in a slow curve to aid their robust engagement within the matching tongue recesses. When the chosen outer jaw tongues are fully inserted within their lower jaw recesses, the lower jaw abutment faces further robustly contact the outer jaw abutment faces. The tongues having suitably positioned indentations for the engagement of the outer axle locking faces when the locking switch axle is appropriately utilized, conversely the locking switch axles can be suitably rotated wherein the unlocking faces of the said switch axle are substantially in line with the profile of the jaw interlocking tongue indentations in order to provide straightforward engagement or withdrawal of the chosen outer jaw from the lower jaw. 
     The interchangeable jaws pliers may comprise first and second lower jaws having strong permanent magnets fitted such that their magnetic field can suitably act on the metal leading end of the interlocking tongue portions, the said magnets magnetic force robustly locking the detachable jaw or jaws in place within the said lower jaws, in order to remove a detachable jaw the operator requires to open the jaws and forcefully pull the detachable jaw from the interlocking tongue recess. This construction allows the first and second lower jaw portions to be more cost effectively formed in one piece such as an investment casting without the requirement of separate outer cover plates. 
     In some examples, the said strut second end being in a generally cylindrical form whereas during assembly said strut can be rotated whereby the second end pin can be usefully inserted into the second handle strut channel, rotated until the second end axle pin engages into the strut end retention slots and the assembly continued, this construction allows the second handle to be formed in one piece such as an investment casting without the requirement of second handle outer plates or a separate cover plate. 
     In some examples, there is no handle bowed resilient portion incorporated, the pliers operation still incorporating interchangeable jaws or being switchable between locking and unlocking of the handles. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order that the invention may be well understood, some examples will be described with reference to the drawings, in which: 
         FIG. 1  is a perspective view of the interchangeable jaw pliers; 
         FIG. 2  is a plan view of the interchangeable jaw pliers; 
         FIG. 3  is an enlargement of the circled portion of  FIG. 2 ; 
         FIG. 4  is a plan view of the interchangeable jaw pliers with a part shown in section; 
         FIG. 5  is an enlargement of the sectioned part of  FIG. 4 ; 
         FIG. 6  is a view corresponding to  FIG. 5  showing an alternative position; 
         FIG. 7  is a perspective view of the interchangeable jaw pliers showing a workpiece clamped by the pliers; 
         FIG. 8  is an exploded perspective view of the interchangeable jaw pliers; 
         FIG. 9  is an exploded perspective view of a detachable jaw of the interchangeable jaw pliers; 
         FIG. 10  shows a handle and pivotal strut of the interchangeable jaw pliers; and 
         FIG. 11  is a perspective view of another interchangeable jaw pliers. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows interchangeable jaw pliers  1  at rest. The interchangeable jaw pliers  1  comprises a head portion  200  and a handle portion  300 . The handle portion  300  comprises a first handle  301  and a second handle  302  and respective first and second jaw mountings  208 .  209  at one end. The head portion  200  comprises detachable jaws  205  that have respective tongue portions  218 . The jaw mountings  208 ,  209  may be provided with respective jaw locking switches  603 . A jaw pivot pin  600  may be provided to permit relative pivoting movement of the first and second handles  301 ,  202 . The first and second handles  301 ,  302  may comprise a laminate structure. For example, the first handle  301  may comprise top and bottom plates  309  ( FIG. 7 ) that define the outer major faces of the handle. Similarly, the second handle  302  may comprise top and bottom plates  311  ( FIG. 7 ) that define the outer major faces of the handle. 
       FIG. 2  shows the interchangeable jaw pliers  1  with the top plates  309 ,  314  removed from the first and second handles  301 ,  302  to illustrate a pivotal strut  400 , a pivotal switch  500  and switch cam block  509 . The pivotal switch  500  is shown in a disengaged position. The detachable jaws  205  are shown comprising gripping faces  203  and abutment faces  220 . The first and second jaw mountings are shown provided with assembly holes  204  and fixings  602 . 
       FIG. 3  shows the pivotal switch  500  in its unlocked position. In this position, the actuating end  507  of the switch biasing pin  506  is engaged with an open profile  510  of the switch cam block  509  ensuring that the switch locking teeth  503  provided on the pivotal switch  500  are disengaged from the strut teeth  402 . 
       FIGS. 4 and 5  show the interchangeable jaw pliers  1  with the top plates  309 ,  314  of the first and second handles  301 ,  302  removed to illustrate the pivotal strut  400 , pivotal switch  500  and switch cam block  509 . The pivotal switch  500  is shown in section to illustrate a switched locking mechanism, which can be operated to cause the switch locking teeth  503  to engage the strut teeth  402 . &lt;The strut teeth  402  may be provided on an arcuate side, or edge, surface  401  of the pivotal strut  400 &gt; to positionally lock a clamped workpiece  80  between the detachable jaws  205 . The pivotal switch  500  can also be operated to cause the switch locking teeth  503  from the strut teeth  402  to release the workpiece  80  from the detachable jaws  205 .  FIG. 4  indicates a clenching force C applied to the handle gripping portions  303  to squeeze the first and second handles  301 ,  302  to cause the workpiece  80  to be clamped between the detachable jaws  205 . An axle  405  is held within the retention slots  317  with a further strut end contact surface  316  available. The first and second handles  301 ,  302  when operated to move the detachable jaws  205  together act against a spring  70  connected between a spring attachment hole  406  and a spring attachment portion  222  provided on the first handle  301 . The spring  70  acts to bias the first and second handles  301 ,  302  towards an open position when the pivotal switch  500  is in an unlocked position. The switch spring  71  biases the biasing pin  506  so that the actuating end  507  of the biasing spring  56  is pressed against the closing profile  511  of the switch cam block  509  as the handle portion  300  is operated to clamp the workpiece  80 . The resiliently biased biasing pin  506  acts to provide a ratchet action between the switch locking teeth  503  and the strut teeth  402  as the pivotal strut  400  is pivoted by its second end  403  interacting with the handle strut end contact surface  316 . The pivotal strut  400  is retained by the strut second end axle  405  within the retention slots  317 . The strut teeth  402  and the switch locking teeth  503  may have a saw tooth configuration, or profile, to provide an extra safety locking feature, whereby the pivotal switch  500  when moved to an unlocked position still requires the clenching, or squeezing together, of the first and second handles  301 ,  302  to disengage the switch locking teeth  503  from the strut teeth  402  to release the gripping force applied to the workpiece  80 . 
       FIG. 5  shows the pivotal switch  500  in its locked position. The switch biasing pin  506  actuating end  507  is shown engaged with the closing profile  511  on the switch cam block  509  to ensure that the switch locking teeth  503  are pushed towards, or into, the strut teeth  402  on the pivotal struct  400 . Further illustrated are the pivotal switch axle  501 , biasing pin bore  504 , actuator  505 , biasing pin  506 , biasing pin actuating end  507 , biasing pin spring abutment face  508 , switch spring  71 , open profile  510  and cam block transition profile  512  of an engagement profile  510 ,  511 ,  512  provided on the switch cam block  509 . 
     As shown in  FIG. 6  the pivotal switch  500  may incorporate ratchet functionality. The pivotal switch  500  has a bore  504  that houses a biasing pin  506  and a biasing compression spring  71 . The biasing pin  506  is free to move in a lengthwise direction of the bore  504  against the resilient force of the spring  71 . The actuating end  507  of the biasing pin  506  is rounded or angled with a blunt point for ease of movement against a peaked engagement profile  510 ,  511 ,  512 . The biasing pin  506  is a close sliding fit within the bore  504 , which is configured to allow the biasing pin  506  to easily move back and forth in the bore  504  according to the engagement between the actuating end  507  and the engagement profile  510 ,  511 ,  512 . The engagement profile  510 ,  511 ,  512  is defined by a cam surface of the switch cam block  509 , which may define a recess in a side of the switch cam block. The engagement profile comprises a transition peak  512  with a sloping open profile  510  on one side and a switch closing profile  511  on the other. The pivotal switch  500  can be manually moved using the switch actuator  505 . During operation of the pivotal switch  500 , the biasing pin  506  is pushed into the switch bore  504  against the compression spring  71  as the actuating end  507  moves against the corresponding upwardly sloping engagement profile  510 ,  511  till it traverses the peak of the engagement profile  512  and consequently now engages the chosen downwardly sloping engagement profile at the other side of the peak  510 ,  511 . The switch spring  71  resiliently biases the actuating end  507  against the engagement profile  510 ,  511  to positively resiliently hold the switch locking teeth  503  in respective positions in which the switch locking teeth  503  are engaged with or disengaged from the strut teeth  502 . 
     The switch spring  71  is further utilized to directly cause the switch teeth  503  to act in a ratcheting manner against the strut teeth  402  when the switch  500  is operated in the locked position and the pivotal strut  400  is pivoted around the strut axle  405  as the handles  301 ,  302  are clenched. 
     The switch cam block  509  may be incorporated into a handle spacer  305  or handle  301 ,  302  assembly. 
       FIG. 7  illustrates the interchangeable jaws  1  with the gripping faces  203  of the detachable jaws  205  clamped G upon a workpiece  80 . Handle bend promoting portions  304  providing resilient gripping G of the detachable jaws  205  on the workpiece  80  when a clenching, or squeezing, force applied to the handles  301 ,  302  is released. The gripping force is maintained by the engagement of the switch locking teeth with the strut teeth  402 . As indicated in  FIG. 7 , the locked pivotal strut  400  comprises the base and the bend promoting portions  304  comprise the sides of triangular elastic potential energy structure A. The jaw pivot pin  600  forms the apex of the triangle, with the pivotal switch axle  501  forming another corner. The axle  405  at the second end  403  of the pivotal strut  400  acts via the detachable jaws  205  to apply clamping pressure upon the workpiece  80 , this clamping force G being advantageously resilient in nature. Further illustrated are the second handle strut channel  306 , strut pivot pin hole  307 , switch pivot pin hole  308 , first handle outer and inner plates  309 ,  310 , second handle outer and inner plates  314 ,  315 . 
       FIG. 8  illustrates the Replaceable jaw pliers  1  head portion  200  first  201  and second  202  jaw portions, with one version of detachable jaw  205  shown disengaged, comprising gripping faces  203 , first lower jaw  208 , second lower jaw  209 , inner plate  210 , said outer plate  211 , lower jaw web  212 , detachable jaw  205 , interlocking tongue  218 , interlocking tongue indentations  219 , abutment faces  220 , lower jaw abutment faces  214 , detachable jaw engagement slots  215 , detachable jaw outer plate  217  and inner plate  216 . Jaw locking switch  603 , operating lever  605  and jaw switch unlocking face  606 . The pivotal strut  400 , second end axle  405  is further shown within the strut end retention slot  317 , the pivotal switch  500  actuator  505  is illustrated within the first handle portion  301 . In this laminated example the handles  301 ,  302  and said lower and detachable jaws  205  are held together by fixings  602  through assembly holes  204 ,  213 ,  306 . 
       FIG. 9  shows an example of a laminated detachable jaw  205  in a dismantled condition. The detachable jaws  205  comprise outer plates  217 , inner plate  216 , gripping faces  203 , blade members that form the tongue portions  218 , with indentations  219 , abutment faces  220  and fixing holes  213  for fixings  602 . Also shown in  FIG. 9  are a pair of jaw locking switches  603 . Each locking switch  603  comprises a locking switch axle  604 , outer retaining axles  608 ,  609 , switch locking face  607 , switch unlocking face  606  and a switch operating lever  605 . 
       FIG. 10  illustrates a non-laminate second handle  302  comprising a second handle strut channel  306 , retention slots  317  for the second end of the pivotal strut  400  and second jaw mounting  209  made in one piece. The second end  403  of the pivotal strut  400  may have a generally cylindrical form  407 . During assembly, the pivotal strut  400  can be rotated so that the second end axle pin  405  is in a first condition so that it can be inserted into the second handle strut channel  306  and then rotated until the second end axle pin  405  engages in the retention slots  317 . This construction allows the second handle  302  to be formed in one piece such as an investment casting without the requirement of second handle outer plates  314  or a separate cover plate. 
       FIG. 11  illustrates another example of an interchangeable jaws pliers  1 . The handle portion  300  includes no bend promoting portions such as the bend promoting portions  304  shown in  FIG. 7 . The interchangeable jaw pliers  1  may comprise a set of woodwork clamping detachable jaws  205 , which are shown detached from the handle portion  300 . The first and second jaw mountings  208 ,  209  may be provided with magnet holding slots  318  that at least partially house respective jaw retaining permanent magnets  601 . At least the leading edges  221  of the tongue portions  218  of the detachable jaws  205  may be made of a ferrous material so that when the detachable jaws  205  are push-fit engaged with the first and second jaw mountings  208 ,  209 , the detachable jaws  205  are secured to the handle portion  300  by magnetic forces. The handles  301 ,  302  have first and second jaw mountings  208 ,  209  that can be manufactured more cost effectively in fewer pieces by, for example, investment casting. Optionally, the second end  403  of the pivotal strut  400  may have a cylindrical section  407 . The cylindrical section  407  may be inserted into the second handle strut channel  306  with the strut second end axle  405  extending in the lengthwise direction of the strut channel  306  and then rotated to engage the axle  405  in the retention slots  317 . The first handle  301  preferably uses a switch cover plate  305  fixed by known means as an aid to assembly or servicing.