Locking parallel pliers

Abstract

Pliers (1) comprising jaw (201, 301) portions incorporating gripping faces for the clamping of the desired workpiece (90), three pivotal handle (202) portions and a sprung toothed strut (60) positioned between the handles (202). A bow shaped resilient portion (408) or portions, incorporated within the third arm (200, 300, 400) portion, when the pliers are operated this resilient portion imparts a sprung pressure upon the clamped workpiece (90) by the gripping face (203, 303) of the jaws (201, 301). The third arm (200, 300, 400) and bend promoting portion are contiguous with each other. The jaws (201, 301) can further be usefully locked in the required clamping position upon the workpiece (90) by a toothed sprung strut (60) pivotally attached to the first and third arms (200) and conveniently being locked or unlocked according to the locking switch (500, 50) pivotal within the first arm (200, 300, 400).

Claims

1. Locking parallel pliers comprising: a first handle, a second handle and a third handle, the second handle being disposed between the first and third handles, wherein the third handle is pivotally attached to the second handle by a first pivot pin with a first extension spring between the said first and the third handles biasing the third handle open from the second handle; a first jaw element contiguous with a first end of the first handle and a second jaw element contiguous with a first end of the second handle; a bar extending from said first handle, said bar slidingly received within a channel defined by said second handle and having a surface provided with teeth; and a cam provided at a first end of said third handle, said cam comprising a substantially smooth cam arc portion and a toothed cam arc portion that is contiguous with said smooth cam arc portion, wherein the first and second handles have respective second ends and are pivotally connected by a second pivot pin at at said second ends, wherein a second extension spring is attached between the first and second handles biasing the first and second handles open relative to one another, wherein the first and second extension springs each have a pivotal leverage value, the pivotal leverage value of the second extension spring being less than the pivotal leverage value of the first extension spring in order that closure of the first handle towards the second handle can be initiated whilst movement of the third handle towards the second handle is substantially resisted, wherein said third handle includes a bowed resilient portion within the third handle and a pivotal strut extends between said first and third handles, said pivotal strut having a first end pivotally connected to said first handle and a second end pivotally connected to said third handle via an elongate channel provided in said third handle, wherein said first extension spring is connected to said first end of said pivotal strut, and wherein the arrangement is such that, in use, when a user squeezes the first handle and third handle together the first and second jaw elements can initially close on a workpiece by relative pivotal movement of said first and second handles on said second pivot pin whilst movement of the third handle relative to said second handle is substantially resisted said by said first extension spring and when movement of the second handle is inhibited by said first and second jaws gripping said workpiece, the third can pivot around said first pivot pin against said first extension spring thereby rotating said cam provided on the first end of the third handle so that said smooth cam arc portion is rotated away from said teeth of said bar to bring said toothed cam arc portion into engagement with said teeth.

2. The locking parallel pliers of claim 1, wherein said bowed resilient portion is in the form of a slow curve that arches away from said second handle.

3. The locking parallel pliers of claim 2, wherein said bowed resilient portion subtends an angle from about 40 degrees to about 140 degrees.

4. The locking parallel pliers of claim 3, wherein said third handle has at least one width outside of said bowed resilient portion and said bowed resilient width has a width from about 5% to about 80% thinner than said at least one width outside of said bowed resilient portion.

5. Locking parallel pliers comprising: a first handle having a first end connected with a first jaw and a second end; a second handle having a first end connected with a second jaw and a second end pivotally connected by a first pivot pin with said second end of the first handle; a first biasing member acting between said first and second handles; a third handle pivotally connected by a second pivot pin to said second handle and arranged such that said second handle is disposed between said first and third handle; a second biasing member acting between said second and third handles and a third biasing member acting between said first and third handles, wherein said first, second and third biasing members are configured such that said third biasing member provides a relatively greater bias than said first and second biasing members; an elongate member projecting from said first handle through an opening provided in said second handle and having a side provided with a series of teeth, wherein said third handle comprises a nose portion that engages said teeth and is provided with a relatively smooth portion and a toothed portion; and a locking mechanism for locking said first and second jaws, said locking mechanism comprising a strut pivotally connected with said first handle and having a first end slidingly connected with a groove provided in said third handle and a second end provided with first locking teeth and a switch pivotally connected with said first handle and provided with second locking teeth releasably engageable with said first locking teeth, the arrangement being such that, in use, a user applied force squeezing the first and third handles together causes said first and second handles to close to bring said first and second jaws into engagement with a workpiece disposed between said first and second jaws and at least substantially no movement of said third handle towards said second handle and a resistance to movement of said first jaw towards said second jaw provided by said workpiece engage between said first and second jaws causes said third handle to pivot relative to said second handle moving said relatively smooth portion out of engagement with said series of teeth and engaging said toothed portion with said series of teeth.

6. The locking parallel pliers of claim 5, wherein said first and second locking teeth are saw teeth.

7. The locking parallel pliers of claim 5, wherein said switch is provided with a sliding member mounted in a housing defined in said switch and a biasing member configured to bias said sliding member outwardly of said housing, wherein said sliding member is configured to engage an abutment on said first handle when said first and second locking teeth are engaged, whereby, in use, when said first and second handles are squeezed together said second locking teeth can ratchet over said first locking teeth by sliding movement of said sliding member against said biasing member.

8. Locking parallel pliers comprising: a first handle having a first end connected with a first jaw and a second end; a second handle having a first end connected with a second jaw and a second end pivotally connected by a first pivot pin with said second end of the first handle; a first biasing member acting between said first and second handles; a third handle pivotally connected by a second pivot pin to said second handle and arranged such that said second handle is disposed between said first and third handle, wherein said third handle comprises an arcuate portion arched in a direction away from said second handle and having a width measured in said direction that is at least substantially in the range 5 to 80% less than the width of said third handle outside of said arcuate portion; a second biasing member acting between said second and third handles and a third biasing member acting between said first and third handles, wherein said first, second and third biasing members are configured such that said third biasing member provides a relatively greater bias than said first and second biasing members; and an elongate member projecting from said first handle through an opening provided in said second handle and having a side provided with a series of teeth, wherein said third handle comprises a nose portion that engages said teeth and is provided with a relatively smooth portion and a toothed portion, the arrangement being such that, in use, a user applied force squeezing the first and third handles together causes said first and second handles to close to bring said first and second jaws into engagement with a workpiece disposed between said first and second jaws and at least substantially no movement of said third handle towards said second handle and a resistance to movement of said first jaw towards said second jaw provided by said workpiece engage between said first and second jaws causes said third handle to pivot relative to said second handle moving said relatively smooth portion out of engagement with said series of teeth and engaging said toothed portion with said series of teeth.

9. The locking parallel pliers of claim 8, wherein said arcuate portion subtends an angle at least substantially in the range 40 to 140 degrees.

10. The locking parallel pliers of claim 8, further comprising a locking mechanism for locking said first and second jaws, said locking mechanism comprising a strut pivotally connected with said first handle and having a first end slidingly connected with a groove provided in said third handle and a second end provided with first locking teeth and a switch pivotally connected with said first handle and provided with second locking teeth releasably engageable with said first locking teeth, wherein said switch is provided with a sliding member mounted in a housing defined in said switch and a biasing member configured to bias said sliding member outwardly of said housing, wherein said sliding member is configured to engage an abutment on said first handle when said first and second locking teeth are engaged, whereby, in use, when said first and second handles are squeezed together said second locking teeth can ratchet over said first locking teeth by sliding movement of said sliding member against said biasing member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A full and enabling disclosure of the present Invention including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended drawings, in which:

(2) FIG. 1 is a perspective view of the Parallel Locking Pliers.

(3) FIG. 2 is a plan view of the Parallel Locking Pliers first gripping on a workpiece. The first, second and third arm top plates/top laminates shown removed for illustration purposes.

(4) FIG. 3 is a close up view of the third arm levered end portion, the third arm smooth cam portion abutting the first arm bar toothed profile.

(5) FIG. 4 is a close up view of the pivotal switch in the open or unlocked position, the strut toothed cam teeth disengaged from the pawl locking teeth.

(6) FIG. 5 is a plan view of the Parallel Locking Pliers robustly gripping on a workpiece. The first, second and third arm top plates/top laminates shown removed for illustration purposes.

(7) FIG. 6 is a close up view of the third arm levered end portion, the third arm toothed cam portion engaging the first arm bar toothed profile.

(8) FIG. 7 is a close up view of the pivotal switch in the closed or “ratcheting” position, the strut toothed cam teeth engaged into the pawl locking teeth.

(9) FIG. 8 is a perspective view of the Locking Parallel Pliers, the parts shown dismantled for display purposes.

(10) FIG. 9 is a plan view of the Locking Parallel Pliers, resilient portions shown acting upon the second and third handles.

(11) FIG. 10 is a plan view of the Locking Parallel Pliers, with no deliberate resilient portion.

(12) Among those benefits and improvements that have been disclosed, other objects and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objects and features thereof.

DETAILED DESCRIPTION OF THE INVENTION

(13) As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various forms. The figures are not necessarily to scale, some features may be exaggerated to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the invention.

(14) FIG. 1 illustrates an embodiment of a set of locking parallel pliers 1, the pliers 1 are at rest. Showing the first arm 200, the first jaw element 201 with its gripping face 203 contiguous with the first arm bar 207 and first handle grip 206. The pivotal switch 500, and strut 60 with its spring 70 located between the outer plates 210. The second arm 300 is pivotal to the first arm 200 around the pivot pin 80 within the first arm handle pivot 202. The second arm jaw element 301 with its gripping face 303 is contiguous within the second arm 300. The third arm 400 is pivotal around the pivot pin 81 and the strut 60 is further traversable within the gap 307 between the second arm outer plates 309. The third arm 400, further retains the strut distal end cam retention pin 65 within its pin slot 407, further displayed is the third arm resilient portion 408.

(15) The first embodiment of the present invention 1 relates to a pliers apparatus comprising a switch 500 incorporating a ratchet function R, the switch 500 incorporating a bore 504 for the engagement of a biasing pin 505 and its compression spring 71, the biasing pin 505 being free to move lengthwise within the bore 504 against the resilient force of the spring 71. In best practice the outer end 506 of the positional pin 505 is rounded or angled with a smooth blunt point 506 for ease of movement against a corresponding peaked engagement profile 509, 510 and 511. The pin 505 having a close sliding fit within the bore 504 whereas it can easily traverse inwards or outwards against the spring 71 within the bore 504 according to the engagement between the blunt point 506 and the corresponding peaked 511 engagement profile mounted within the first handle 202. The said switch biasing block 502 engagement profile further comprising of a transition peak 510 with a sloping open profile 511 on one side and a switch closing profile 509 on the other, the pivotal switch 500 can be manually intuitively operated by the operator from either chosen position, during the switch 500 positional operation the positional pin 505 is propelled into the switch bore 504 against the incumbent spring 71 as its outward blunt point 506 moves against the corresponding upwardly sloping engagement profile 509, 511 till it traverses the peak of the engagement profile 510 and consequently now engages the downwardly sloping engagement profile 509, 511 at the other side of the peak 510, the switch spring 71 usefully resiliently propelling the positional pin 505 blunt outward end 506 against its corresponding sloping engagement profile 509, 511 positively resiliently engaging or disengaging the switch teeth 503 from the toothed strut cam teeth 64 according to the operators requirements.

(16) As it is commercially prudent to have a ratchet like clicking noise to accompany the jaw 201, 301 closure and locking procedure the interaction of the resiliently biased switch teeth 503 with the corresponding pivotal strut toothed cam teeth 64, when the switch 500 is in the closing position L provides a typical ratchet R like sound as the strut 60 rotates during the closure procedure C around the strut pivot pin 62 against the resilience of the second arm spring 72 and or without the strut spring 70.

(17) The present invention can even further incorporate a switch 500 incorporating a cost effective ratchet function R, the switch 500 incorporating a bore 504 for the engagement of a biasing pin 505 and its compression spring 71, the positional pin 505 being free to move lengthwise within the bore 504 against the resilient force of the spring 71. In best practice the outer end 506 of the positional pin 505 is rounded or angled with a blunt point 505 for ease of movement against a corresponding peaked 510 engagement profile 509, 511. The pin 505 having a close sliding fit within the bore 504 whereas it can easily traverse inwards or outwards against the spring 71 within the bore 504 according to the engagement between the blunt point 506 and the corresponding peaked 510 engagement profile 509, 510, 511 mounted within the first handle 202 handle. The said switch 500 biasing block 502 engagement profile 509, 510, 511 further comprising of a transition peak 510 with a sloping open profile 511 on one side and a switch closing profile 509 on the other. When the pivotal switch 500 is operated into the closed position L, the strut toothed cam teeth 404 can usefully “ratchet” R over the corresponding teeth 503 on the pivotal switch 500, according to the pressure applied C to the said handles 202, 405. When the operator has reached the level of clamping G required and releases the applied grip C of the said handles 202, 405 the ratchet teeth 503 of the pivotal switch 500 and the corresponding teeth 64 of the strut toothed cam 63 engage in a locking manner L.

(18) As it is commercially prudent to have a ratchet R like clicking noise to accompany the jaw 201, 301 closure G and locking L procedure the interaction of the resiliently biased switch 500 teeth 503 with the corresponding pivotal strut toothed arc teeth 64, when the switch 500 is in the closed position L provides a typical ratchet like sound as the strut 60 rotates during the closure G procedure around the strut pivot pin 62 against the resilience of the strut spring 70 when utilized

(19) FIG. 2 illustrates a further embodiment of a set of locking parallel pliers 1, the pliers 1 are shown first gripping a workpiece 90, the top plates 210, 309 (not shown) being removed for illustration purposes.

(20) The further embodiment of the present invention is the utilization of a third arm 400 which is pivotally attached to the second arm 300. The first jaw element 201 is contiguous with the first arm 200 and the corresponding second jaw element 301 contiguous to the second arm 300, the first and second arms 200, 300 are pivotally connected by a pivot pin 80 at their distal ends. The hand grip squeezing of the operator is made upon the first and third handle lever grips 206, 405 initially in this example against the resilience of the first to second arm spring 72 until the jaws 201,301 as they close initially grip the workpiece 90 to be operated within the jaws 201,301. The strut 60 further pivots around its pivot pin 62 against the strong third arm spring 73 as the strut distal end retention pin 65 is driven down the third arm 400 strut cam pin slot 407 as the third arm 400 is operated to clamp the chosen workpiece 90.

(21) FIG. 3 shows the third arm 400 levered end portion 402 with its smooth cam portion 403 abutting the first arm bar 207 toothed profile 208, the third arm 400 pivotal around the pivot pin 81.

(22) FIG. 4 further illustrates the pivotal switch 500 for demonstration purposes shown in the disengaged position, its sprung actuator 51 at the appropriate end of the actuating profile 55 of the toothed pawl 53 which is pivotal around the pawl pivot 54, the strut cam toothed cam 63 teeth 64 free from the toothed pawl teeth 56.

(23) As further illustrated in FIG. 5 the first and second 200,300 outer plates 210,309 (not shown) are removed for demonstration purposes. The second arm 300 movement now inhibited by the gripped G clamped metal workpieces 91 causes the third arm 400 to further pivot around its pivot pin 81 as clenching force C is further applied, whereas the third arm levered end portion 402 rotates until the substantially smooth cam arc portion 403 transmutes to a second appropriately saw toothed cam arc portion 404 which now usefully engages upon the correspondingly toothed 208 first arm bar 207 slidingly held within a channel or slot 307 within the second arm 300. The third arm 400 as it is further clenched C rotates around its pivot pin 81 robustly closing the first and second jaws 201,301 upon the chosen workpiece 90 as the toothed cam 404 acts upon the bar toothed profile 208. The operator simply choses the level of jaw 201,301 grip G upon the workpiece 90, 91 required by the amount of applied clenching pressure C applied between the first and third arms 200,300.

(24) The present invention 1 can further incorporate clamping widths within its specification that are automatically adjusted, the locking pressure G can be further be usefully determined by the operator by the straightforward gripping pressure C of the said arm grips 206, 405 the simple release of the said grips 206,405 initiating the locking of the said jaws 201, 301 upon the said clamped parts 90, 91 when the switch 500 is in the locking position.

(25) As illustrated in FIGS. 5 and 6 a further embodiment of the present invention is to provide enhanced jaw 201,301 closure only after the jaws 201,301 have first gripped the workpiece 90. As the third arm 400 requires little movement in relation to the second arm 300 during the initial closure sequence which can be variable in relation to the size of the actual workpiece 90,91 operated, the major third arm 400 pivotal movement is still available for the second sequence, the enhanced jaw 201, 301 closure. The enhanced jaw 201, 301 closure is directly equivalent to the ratio of the length from the pivot pin 81 of the third arm levering portion 401 to that of the third arm toothed cam levered portion 402 distance from the said pivot pin 81 which acts as the fulcrum, even using shorter than standard handle 202,401 lengths a closure force ratio of 10 to 1 or better is attainable compared to a standard 5 to 1 with regular long handles.

(26) As illustrated in FIGS. 5 and 7 a further embodiment of the present invention is to provide a useful clamping device. There are a myriad of reasons for using such a device 1 from clamping and gripping in order to turn a fastener 90, especially a worn or damaged one to clamping two pieces of metal 91 together prior to welding them. The common failing in the prior art devices is if the clamped object or objects were to reduce their clamp width even slightly for whatever reason the solid grip imparted by these prior art devices would result in the failure of the devices ability to sustain further grip G upon the objects.

(27) In order to overcome these failings, the present device 1 deliberately incorporates an extremely strong method of resiliently closing or further locking closed the tools 1 grip via its jaws 201, 301 of the worked objects 90, 91.

(28) In one example, the resilient portion 408 is incorporated within the third arm 400 between the third arm levered portion 402 and the third arm levering portion 401. The profile, material and thickness of the said resilient portion 408 is carefully chosen in order to provide a repeatable resilience with the least chance of stress cracking during repeated use. The profile is in best practice a slow curve or arc 408 in the direction of the closing arm 400 force C. The flex induced within the living spring portion 408 and the gripping jaws 201, 301 upon the clamped parts 90, 91 is retained by the angle of the strut 60 and the strut distal end cam retention pin 65 within the third arm pin slot 407. The arc 408, strut 60 locked in position by its engagement with the toothed pawl 53 within the first arm 200 and the said first arms bar 207 engagement with the third arms toothed cam portion 404 forms a very robust frame placing the jaws 201, 301 under useful resilient gripping tension G. If the clamped parts 90, 91 were subjected to movement or vibration which would defeat the fixed clamping effect of prior art devices the present device 1 would still retain its grip G albeit a lessor one. The utilization of a said bowed resilient portion 408 within the third arm 400 providing superior constant said jaw 201, 301 clamping pressure of the said part or parts 90,91 clamped, whilst normally preventing surface damage to the said parts 90,91. The bowed said bend promoting portion or portions 408 exerting elastic potential energy to usefully spring clamp G, the said workpiece 90, 91 between the opposing jaws 201, 301. As even further illustrated in FIG. 5 the retained pivotal strut 60 thereby comprises a base of a triangular elastic potential energy structure A, the resilient portion 408 further comprising the side of the triangle A and the jaw pivot pin 81 as the apex, this formation usefully acts via the connected jaws 201, 301 to provide strong clamping pressure G to the said jaws 201, 301 upon the workpiece 90, 91 this clamping pressure G being advantageously resilient in nature.

(29) The present invention further works on a reasonable range of said workpiece 90,91 sizes and shapes whilst utilizing superior said sprung gripping force G upon the said workpiece 90,91. FIG. 7. Illustrates the pivotal switch 500 locking teeth 503 engaged upon the strut toothed cam teeth 64. As the said teeth 503, 64 are saw like in profile the first arm grip 206 and the third arm grip 405 need to be clenched C to finally allow the release of the locking switch mechanism 500 teeth 56 and strut teeth 64 even if the switch 500 is de-operated, usefully providing a further safety lock.

(30) FIG. 8 illustrates the said Pliers 1, although the composition could consist of mainly cast or forged parts for example, for cost effectiveness the construction shown comprises a semi-laminate like assembly, furthermore the main parts are capable of being stamped or HPM (high pressure moulded) in order to further reduce their manufacturing cost. The various parts are shown dismantled for display purposes.

(31) Referring to FIGS. 1, 2, 5, 9 and 10, the said Parallel Locking Pliers 1 includes, an even further embodiment, comprising a closure sequence, whereas the actual pivotal locations change during the operation of the handle portion 206, 405 clenching. At rest the said arms 200, 300 and 400 with their said jaws 201,301 are urged into their respective open positions by the strut spring 70 and/or the second, third arm springs 72, 73. When the grips 206, 405 are first clenched the second arm 300 with its attached third arm 400 pivots around the pivot pin 80, the first arm bar 207 moving without difficulty within the second jaw slot 307, the adjacent bar smooth portion 212 presenting little resistance to the said second jaw internal contact surface 306 and the third arm smooth cam portion 403 presenting little resistance to the said toothed face 208 of the adjacent first arm bar toothed profile 208 whose saw shaped teeth 208 are in the angle of the least resistance. The strength of the said strut spring 70 or the third arm spring 73, usefully preventing undue third arm 400 to second arm 300 compression during this action, the applied handle grip 206, 405 clenching force C being directed towards the said second jaw 301 being propelled towards the said first jaw 201, till it abuts the said workpiece 90,91 to be operated or clamped, situated between the said opposing jaws 201,301. The said workpiece 90 now lightly grasped between the said first 201 and said second jaws 301 changes the said first and second arm 200, 300 said pivot point 80 to that of the said second arm 300 to third arm 400 pivot point 81. The pivotal strut 60 in the first instance also slightly pivoting as required around the strut pivot pin 62. As the third arm 400 is further robustly clenched C towards the first arm 200 the third arm toothed cam 404 engages the first arm bar toothed profile 208 forcefully closing as required the jaws 201, 301 upon the engaged workpiece 90,91.

(32) FIG. 9 illustrates a further example of the present invention the said parallel locking pliers 1 wherein the said pliers 1 are shown in the initial clamped position upon clamped metal plates 91. The top first and second arm outer plates 210, 309 removed for display purposes. The strut spring 70 is further removed and substituted by a second arm spring 72 in this example held between a spring end pin 83 mounted within the first arm 200 and the second arm spring lever 311 hole 312, the said spring 72 usefully propelling the first and second arms 200, 300 into their open position when the locking mechanism 50, 53 and 63 is de-activated. A further stronger third arm spring 73 is fitted between the third arm sprung lever portion 418 sprung hole 417 and in this example a spring end pin 83 mounted within the third arm 400. In use the said strong third arm spring 73 substantially prevents the third arm 400 unduly progressing relative to the second arm 300 whilst the second arm 300 jaw element 301 initially closes upon the workpiece 90, 91 now as illustrated lightly held between the said second arm jaw gripping face 303 and the first jaw gripping face 203. Once this first sequence is complete any further clenching force C applied to the first and third arms 200, 400 will result in the second jaw 301 being very robustly propelled towards the first jaw 201 as the third arm 400 pivots around the second to third arm pivot 81 forcefully engaging the third arm toothed cam portion 403 teeth within the first arm bar toothed profile 208 usefully providing the gripping force G required upon the held workpiece, the said gripping force G simply and expediently set by the operators level of clenching force C applied to the handle grips 206, 405. The operator having the further choice of merely gripping the said workpiece 90, 91 or locking the jaws 201, 301 upon the said workpiece 90, 91 according to the operated position of the switch 50.

(33) FIG. 10 illustrates a further example of the present invention the said parallel locking pliers 1 wherein any of the said arms 200,300 and 400 do not incorporate any said arm bend promoting portions as illustrated by 408. In all other respects the device 1 is as illustrated in FIGS. 1, 2, 5 and 9