Pliers

Abstract

A pliers has jaw portions incorporating gripping faces for the clamping of the desired workpiece, two pivotal handle portions and a sprung toothed strut positioned between the handles. A bow shaped resilient portion, incorporated within the second arm portion, when the pliers are operated this resilient portion imparts a useful superior sprung pressure upon the clamped workpiece by the gripping face of the jaws. The second arm and bend promoting portion are contiguous with each other. The jaws can further be usefully locked in the required clamping position upon the workpiece by a toothed sprung strut pivotally attached to the first and second arms and conveniently being locked or unlocked according to the locking switch pivotal within the first arm.

Claims

1. Pliers comprising: a first jaw connected with a first handle; a second jaw connected with a second handle that is pivotally connected to said first handle by a pivot pin extending through said first and second handles; and a locking mechanism for locking said first and second jaws, wherein said second handle comprises an arcuate portion that arches in a direction away from the first handle, wherein said second handle has a length defined between said pivot pin and a free end of said second handle and a width measured in said direction away from the first handle, wherein said width of the arcuate portion of the second handle is at least substantially in the range 5 to 80% less than the width of said second handle outside of said arcuate portion, said locking mechanism comprises a strut pivotally connected with said first handle and having a first end slidingly connected with a groove provided in said second 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 a fixed abutment on said first handle and said fixed abutment defines a profile configured such that when said sliding member engages a first portion of said profile said second locking teeth are disengaged from said first locking teeth and when said sliding member engages a second portion of said profile said second locking teeth engage said first locking teeth, and wherein said first and second locking teeth are configured such that when engaged and 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.

2. The pliers of claim 1, wherein said arcuate portion subtends an angle at least substantially in the range 40 to 140 degrees.

3. The pliers of claim 1, wherein said first and second locking teeth are saw teeth.

4. The pliers of claim 1, wherein said second handle comprises a first end portion that defines pivot hole for said pivot pin and a second end portion that defines said free end and said arcuate portion is disposed intermediate said first and second end portions.

5. The pliers of claim 1, wherein said arcuate portion is disposed closer to said pivot pin than to said free end.

6. The pliers of claim 5, wherein the arcuate portion is situated between said pivot pin and a hand gripping portion of the second handle.

7. The pliers of claim 1, wherein said profile defines a ramp portion connecting said first portion with said second portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The drawings show examples of pliers according to the invention as follows:

(2) FIG. 1 is a perspective view of an embodiment of pliers according to the invention;

(3) FIG. 2 is a plan view of the pliers shown gripping a workpiece with the first and second arm top plates/top laminates shown removed for illustration purposes;

(4) FIG. 3 is a close-up plan view of a switch mechanism of the pliers with the switch shown in an unlocked position;

(5) FIG. 4 is a plan view of the pliers gripping a workpiece, with the first and second arm top plates/top laminates shown removed for illustration purposes;

(6) FIG. 5 is a close-up plan view of the switch mechanism of the pliers with the switch shown in a locked position;

(7) FIG. 6 is a close-up plan view of the switch mechanism of the pliers with the switch o shown in a locked position and the strut teeth ratcheting against the switch teeth;

(8) FIG. 7 is a plan view of an embodiment of pliers according to the invention with no deliberate resilient portion fitted, and the first and second arm top plates/top laminates shown removed for illustration purposes; and

(9) FIG. 8 is an exploded perspective view of pliers according to the invention.

DETAILED DESCRIPTION

(10) As required, detailed embodiments of the 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. FIGS. 1 to 8 display the various embodiments of the present invention.

(11) FIG. 1 illustrates the pliers 1 at rest. Showing the first arm 20, the first jaw element 21 with its gripping face 26. The pivotal switch 50, strut 40 and its strut pivot 41. The second arm 300 is pivotal to the first arm 20 around the axle pin 60. The second arm jaw element 301 with its gripping face 303 is contiguous within the second arm 300. The second arm 300 further retains the strut distal end cam retention pin 42 within its pin slot 305, further displayed is the second arm resilient portion 304, first arm handle 22 and second arm handle 302. Further shown are the strut 40 rotatable around its pivot 41.

(12) The pliers 1 may further incorporate 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 said arm handle portions 22, 302 the simple release of the said handles 22, 302 initiating the locking of the said jaws 21, 301 when the switch 50 is in the locking position L.

(13) FIG. 2 shows the pliers 1 gripping a workpiece 80, the top plates 23, 307 (not shown) being removed for illustration purposes.

(14) The pliers 1 may comprise a switch mechanism 500 which is pivotally attached within the first arm 20. The first jaw element 21 is contiguous with the first arm handle 22 and the corresponding second jaw element 301 contiguous to the second arm handle 300, the first and second arms 20, 300 are pivotally connected by an axle pin 60 at a point between the jaws 21, 301 and the handle portions 22, 302. The hand grip squeezing C of the operator is made upon the first and second handle lever portions 22, 302 initially against the resilience of the strut spring 70 until the jaws 21, 301 as they close initially grip the workpiece 80 to be operated within the jaws 21, 301. The strut 40 further pivots around its pivot pin 41 against the strong strut spring 70 as the strut distal end retention pin 42 is driven down the second arm 300 strut cam pin slot 305, the strut distal end cam 45 engaging the smooth strut cam channel profile 306. There resilient portion 304 only bowing according to the level of clenching force C applied as the handles 22, 302 are operated.

(15) The pliers 1 may comprise an intuitive switch locking, unlocking or ratcheting mechanism 500 utilizing less parts than the prior art type tools comprising pivotal struts 40 utilizing toothed cams 43 interacting with a switch 500. The switch 500 usefully now directly incorporates the locking L, ratcheting R or disengaged U teeth 503 mechanism 500 according to their chosen orientation, which can be usefully utilized as required to engage with the teeth 44 of the toothed strut arc 43 to positionally lock as required the same, thereby locking the clamped G workpiece 80 within the jaw portions 21, 303, or alternately disengaging U the switch teeth 503 from the strut toothed cam 43 releasing the workpiece 80 from the jaws 21, 303, according to the pivotal switch 500 orientation.

(16) FIG. 3 shows in close up an intuitive reduced parts count pivotal switch mechanism 500 in its unlocked position U whereas the switch biasing pin 506, actuating end 507 is engaged upon the switch biasing block 502 open profile 510 ensuring that the switch locking teeth 503 are disengaged from the strut cam teeth 44.

(17) The switch 500 locking, unlocking, ratcheting mechanism utilizes less parts than previous pliers type tools comprising pivotal struts 40 with toothed arcs 43 interacting with a switch 500. The switch 500 usefully now directly incorporates the locking L, ratcheting or disengaged U teeth according to their chosen orientation, which can be usefully utilized as required to engage with the teeth 44 of the toothed strut cam 43 to positionally lock as required the same, thereby locking the clamped G workpiece 80 within the jaw portions 21, 301 or alternately disengaging U the switch teeth 503 from the strut toothed cam 43 releasing the workpiece 80 from the jaws 21, 301 according to the pivotal switch 500 orientation.

(18) As shown in FIG. 4 in another embodiment the pliers 1 is provided with enhanced jaw 21, 301 closure only after the jaws 21, 301 have first gripped the workpiece 80, 81.

(19) As shown in FIGS. 4 and 5 another embodiment of the pliers 1 is provided with a clamping device. There are a myriad of reasons for using such a pliers 1 from clamping and gripping G in order to turn a fastener 80, especially a worn or damaged one to clamping two pieces of metal 81 together prior to welding them. The common failing in the prior art devices is if the clamped object or objects 80, 81 were to reduce their clamp width even slightly for whatever reason the solid grip imparted by prior art devices would result in the failure of the devices ability to sustain further grip upon the objects 80, 81.

(20) In order to overcome these failings, the pliers 1 deliberately incorporates an extremely strong method of resiliently closing or further locking closed the pliers 1 grip via its jaws 21, 301 upon the worked objects 80, 81.

(21) A resilient portion 304 may be provided in the second arm 300 between the second arm levered or jaw portion 21 and the second arm levering or handle portion 302. The profile, material and thickness of the said resilient portion 304 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 304 in the direction of the closing arm handle 302 force. The flex induced within the living spring portion 304 and the gripping jaws 21, 301 upon the clamped parts 80, 81 is retained by the angle of the strut 40 and the strut distal end cam retention pin 42 within the second arm pin slot 305. The arc 304 and strut 40 locked in position by the strut's 40 engagement with the toothed within the first arm 20 forms a very robust frame, placing the jaws 21, 301 under useful resilient gripping tension. If the clamped parts 80, 81 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 albeit a lesser one. The utilization of a said bowed resilient portion 304 within the first arm 20 providing superior constant said jaw 21, 301 clamping pressure of the part or parts 80, 81 clamped, whilst normally preventing surface damage to the said parts 80, 81. The bowed said bend promoting portion or portions 304 exerting elastic potential energy to usefully spring clamp, the said workpiece 80, 81 between the opposing jaws 21, 301. As even further illustrated in FIG. 4 the retained pivotal strut 40 thereby comprises a base of a triangular elastic potential energy structure A, the resilient portions 304 further comprising the side of the triangle A and the jaw pivot pin 600 as the apex, this formation usefully acts via the connected jaws 21, 301 to provide clamping pressure to the said jaws 21, 301 upon the workpiece 80, 81 this clamping pressure being advantageously resilient in nature.

(22) FIG. 5. shows the switch 500 locking teeth 503 engaged upon the strut toothed cam teeth 44. As the said teeth 503, 44 are saw like in profile the first arm handle 22 and the second arm handle 302 need to be clenched C to finally allow the release of the locking mechanism 500, 43.

(23) FIG. 6 shows in close up a further embodiment of the pliers 1 where, in order to provide a method of adjusting the gripping, clamping pressure G exerted by the jaws 201, 202, the pivotal strut 40 is rotatable around the strut pivot 41, when the handles 301, 302 are clenched C closing the jaws 201, 202 upon the workpiece 80 etc. As the handles 301, 302 are further activated, pivoting around the axle pin 60, the pivotal strut 40, toothed strut cam 43 teeth 44 “ratchet” R over the corresponding switch teeth 503 on the switch 500 according to the clenching force C applied. When the operator has reached the level of gripping force G required and releases the applied grip C from the handles 301, 302 the said pivotal strut and switch teeth 44, 503 engage in a locking manner providing the switch 500 is biased in the locking position L. The flex induced within the living spring portions 304 and the clamping G of the jaws 201, 202 upon the clamped parts 80 is retained by the pivotal strut 40 retention by the switch locking teeth 503 upon the strut toothed cam 43 teeth 44. The strut toothed cam 43 strut retention pin 42 is usefully retained as required within the strut cam retention slot 317.

(24) FIG. 7 another embodiment of the pliers 1 wherein the said arms 22, 302 do not incorporate any said arm resilient portions 304. In all other respects the pliers 1 is as illustrated in FIGS. 1, 2, 3, 4, 5 and 6.

(25) 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 laminate assembly, whereas the parts are shown dismantled for display purposes. Comprising of First Jaw Portion 21, First Arm Handle 22, First Arm Outer Plates 23, First Arm Axle Hole 24, First Arm Jaw Inner 25, First Jaw Gripping Portion 26, First Arm Spacer 27, First Arm Handle Spacer 28, First Arm Assembly Holes 29, Second Arm 300, Second Arm Jaw Portion 301, Second Arm Handle 302, Second Jaw Gripping Portion 303, Resilient Portion 304, Strut Cam Pin Slot 305, Strum Cam Channel Profile 306, Second Handle Outer Plates 307, Second Arm Jaw Outer Plates 308, Second Arm Axle Hole 309, Second Arm Assembly Holes 310, Strut 40, Strut Pivot 41, Strut Retention Pin 42, Strut Toothed Cam 43, Strut Toothed Cam Teeth 44, Strut Distal End Cam 45, Switch 500, Switch Axle 501, Switch Biasing Block 502, Switch Teeth 503, Biasing Pin Bore 504, Switch Actuator 505, Biasing Pin 506, Biasing Pin Actuating End 507, Biasing Pin Spring Abutment End 508, Biasing Block Closing Profile 509, Biasing Block Open Profile 510, Biasing Block Transition Peak 511, Axle Pin 60, Assembly Rivets 61, Strut Spring 70, Switch Spring 71.