Large jaw universal pliers structure

Abstract

A large-jaw universal pliers structure comprises: a first handle, a shaft, a limiting clamping member, a movable clamping member, an elastic member, a second handle, an unlocking member, a connecting rod, and a screw. The supporting head sidewall of the first handle has a through-hole; the shaft passes through the through-hole; the assembly part of the limiting clamping member is attached to the shaft outside the sidewall, and extends a limiting clamping arm with a first chuck; the movable clamping head of the movable clamping member is located on the other side of the sidewall, with one end extending a movable clamping arm with a second chuck, and the other end having a pivot part pivotally connected to the supporting head, and a first pivot joint pivotally connected to the second handle. The overall structure allows for significant improvement in the clamping capacity of the pliers for the target workpiece by adjusting the jaw size within the length of the shaft.

Description

Technical Field

[0001] This invention relates to a large-jaw universal pliers structure that can significantly improve the clamping range of target workpieces. Prior Technology

[0002] According to the prior art description of the conventional universal clamp, as stated in the patent application No. M449066 of the Republic of China, it has a fixed clamp handle 11, a movable clamp handle 12 that swings relative to the fixed clamp handle 11 to an open state and a closed state, an elbow locking element 13 that is pivotally connected to the movable clamp handle 12 and extends to the fixed clamp handle 11 and terminates at a free end 131, and an adjusting screw 14 that is rotatably screwed onto the fixed clamp handle 11 in response to the elbow locking element 13.

[0003] The fixed pliers handle 11 has a first handle 111 and a fixed jaw portion 112 connected to one end of the first handle 111. The movable pliers handle 12 has a second handle 121 that opens and closes relative to the first handle 111, and a movable jaw portion 122 that opens and closes relative to the fixed jaw portion 112 and is pivotally connected between one end of the second handle 121 and the fixed pliers handle 11.

[0004] The adjusting screw 14 has a screw 141 that is rotatably screwed onto the first handle 111 and abuts against the free end 131 of the elbow locking element 13, and a cylindrical adjusting knob 142 that is connected in the opposite direction to the elbow locking element 13 to the end of the screw 141 that protrudes from the first handle 111.

[0005] In use, the fixed jaw 11 and the movable jaw 12 can be opened first so that the workpiece 15 to be clamped is located between the fixed jaw 112 and the movable jaw 122. Then, force is applied to the first and second handles 111 and 121 to firmly clamp the workpiece 15. Next, by further turning the adjusting knob 142 of the adjusting screw 14, the tightness of the fixed jaw 112 and the movable jaw 122 on the workpiece 15 can be increased, so that the workpiece 15 is still firmly locked and clamped even when the first and second handles 111 and 121 are not continuously subjected to force. This allows adjustment of the force applied by the fixed jaw 112 and the movable jaw 122 to the clamped and locked workpiece 15.

[0006] The aforementioned conventional universal clamp, although it can clamp the workpiece 15 by applying force through the gripping of the first and second handles 111 and 121, operates the fixed jaw 112 and the movable jaw 122 to clamp the workpiece 15. However, its clamping ability for the workpiece 15 is limited to workpieces within the swing angle range between the movable jaw 122 and the fixed jaw 112, and it cannot arbitrarily expand the jaws to clamp larger workpieces. Even the aforementioned patent (M449066), or other known universal clamps, such as the invention patent application No. 1411498 of the Republic of China, maintain the same jaw design. Based on the mechanism or conditions of the movable jaw swinging to clamp the workpiece, the clamping ability range cannot be increased by expanding the jaws because the size of the jaws is limited to a certain range. Summary of the Invention

[0007] The main objective of this invention is to provide a large-jaw universal pliers structure, which is a clamp comprising: a first handle, extending from one end of a C-shaped gripping portion to form a support head, and having a screw hole at the other end; the support head having a side wall on its ventral side, and a through-hole formed thereon on the side wall; a shaft, a long rod with a cross-section opposite to the through-hole shape, passing through the through-hole and mounted on the support head, with the axis of the long rod defined as a working center line of the clamp; a limiting clamping member, located outside the side wall of the support head, mounted on the shaft, having a side abutting the shaft and an assembly portion fixed on the shaft, the assembly portion extending from one end above the workpiece center line away from the shaft to a limiting clamping arm, the limiting clamping arm being a nearly inverted U-shaped arm with a first chuck at its end; and a movable clamping member, located on the other side of the side wall of the support head, opposite to the support head. Corresponding to the assembly surface of the limiting clamp, a movable clamp head is provided on the same surface as the assembly part and adjacent to the shaft. At one end of the movable clamp head above the working center line, away from the shaft, a movable clamp arm extends. At the corner of the edge below the working center line, a pivot portion pivotally connected to the support head and a first pivot portion away from the support head are respectively provided. The movable clamp arm, corresponding to the limiting clamp arm, is a nearly U-shaped arm with a second clamp at its end. Furthermore, a pull-out portion is provided between the pivot portion and the first pivot portion of the movable clamp head. An elastic element, one end of which is... A grip is fixed to the holding part, with one end connected to the pull part, used to pull the movable clamp back to its original position after swinging; a second grip is attached to a first pivot part at one end of a grasping part, with a first pivot pin at the other end and a second pivot pin at a distance from the tail; a third pivot pin is provided between the first and second pivot pins; an unlocking member is pivotally connected to the second pivot pin at its middle part, with a push part at one end of the pivot position and an unlocking operation part at the other end; a connecting rod has an arcuate protrusion relative to the push part, with one end of the arcuate protrusion pivotally connected to the third pivot pin and the other end extending to the holding part, forming a stop part; a screw, It is screwed into the screw hole, with one end abutting the stop on the gripping part and the other end extending out of the screw hole, forming a rotating operating head: so that when the second chuck of the clamp is blocked or restricted, only the first handle and the second handle need to be close to each other to apply force. In the initial stage of force application, the first handle will first swing at an angle to cause the through-shaft hole to clamp the shaft, so that the support head achieves a fixed effect on the shaft. In the later stage of force application, the swing of the second handle around the first shaft pin will push the movable clamp to swing through the support of the connecting rod, so that the second chuck of the movable clamp arm can generate a clamping force in the direction of the first chuck.

[0008] That is, when the clamp is to be used to clamp the target workpiece, the shaft can be adjusted left and right on the support head of the first handle, so that the first chuck and the second chuck are placed against the target workpiece; when the second handle is applied to the first handle to tighten, the reaction force generated by the target workpiece blocking the second chuck causes the first handle to swing, so that the support head can first clamp the shaft through the through hole in the initial stage of the second handle tightening, thus fixing the position of the pivot part; in this way, the continuous tightening operation of the second handle, through the limiting support of the second handle by the connecting rod, can be achieved by the slight swinging motion of the first shaft pin around the pivot part, so that the movable clamp arm can complete the clamping action on the target workpiece through the second chuck while the limiting clamp arm and the first chuck are fixed.

[0009] The overall clamp structure allows for easy adjustment of the jaw size between the first and second chucks over a long distance within the length of the shaft to accommodate the clamping of ultra-large target workpieces, thereby significantly improving or expanding the clamp's ability to clamp target workpieces.

[0010] A second objective of this invention is to provide a large-jaw universal pliers structure, wherein the through-hole of the support head of the first handle is a flat elongated hole, and the shaft, with a cross-section relative to the through-hole shape, is a long rod of a ruler-shaped flat iron that can freely slide in and out of the through-hole; by forming a surface contact between the shaft and the movable jaw head of the movable pliers, the swinging motion of the movable pliers can be limited or guided by the surface of the shaft during the swinging motion of the movable jaw head, thereby reducing swaying or deviation.

[0011] Another objective of this invention is to provide a large-jaw universal pliers structure, wherein the support head of the first handle is fixed with at least one stop post close to the shaft above and below the working center line, respectively; by having at least one stop post above and below the working center line of the support head to assist the through hole in supporting the shaft, in addition to increasing the resistance of the through hole to deformation, it can also reduce the excessive horizontal tilt of the two ends of the shaft when it passes through the through hole.

[0012] Another objective of this invention is to provide a large-jaw universal pliers structure, wherein the assembly portion of the limiting pliers is fixed to the shaft outside the non-movable pliers end on one side of the sidewall of the support head; by fixing the assembly portion of the limiting pliers to the shaft, the relationship between the first chuck and the shaft is fixed, so that the pliers can be moved left and right by the shaft through the through hole of the support head to adjust the jaw size of the pliers.

[0013] Another objective of this invention is to provide a large-jaw universal pliers structure, wherein the assembly portion of the limiting pliers abuts against the shaft. The assembly portion forms a cross-connector, and a shaft hole is formed on the cross-sectional shape of the shaft, through which the shaft passes, and the assembly portion is assembled onto the shaft. When the first jaw of the limiting pliers is obstructed, the assembly portion slightly tilts at an angle, causing the shaft hole to clamp the shaft, preventing it from sliding to the distal end. This allows the pliers to shift from their assembly position on the shaft, adjusting the jaw size. Furthermore, the end of the cross-connector of the assembly portion is shaped as follows: The assembly includes a support plate that, together with the assembly part, abuts against both sides of the shaft. When the first chuck is used to clamp the target workpiece, the clamping action of the support plate on the shaft reduces the swaying of the limiting clamp arm under force. Furthermore, the first chuck is provided at the end of the limiting clamp arm extending from one end of the assembly part. The first chuck is approximately T-shaped and has a first clamping surface. The opposite ends of the first clamping surface are pivotally mounted on the end of the limiting clamp arm by a first pivot. The first chuck allows swinging on the end of the limiting clamp arm. Even if the assembly part sways to clamp the shaft, the first clamping surface of the first chuck can still be firmly supported on the target workpiece.

[0014] Another objective of this invention is to provide a large-jaw universal pliers structure, wherein the movable jaw arm of the movable jaw member is provided with a second chuck. The second chuck is approximately T-shaped and has a second clamping surface. The opposite ends of the second clamping surface are pivotally mounted on the end of the movable jaw arm via a second pivot. The second chuck allows the movable jaw arm to swing towards the target workpiece, and the second clamping surface of the second chuck can naturally adjust to fit against the target workpiece, thus solidly transmitting the clamping force to the target workpiece.

[0015] Another objective of the present invention is to provide a large-jaw universal pliers structure, wherein at least one end of the long rod of the shaft is provided with a limiting member protruding from the surface of the long rod, so that the limiting member can restrict the shaft from detaching from the support head. Simple Explanation of the Diagram

[0016] Figure 1 is a plan view of the structure of the present invention.

[0017] Figure 2 is a cross-sectional view of the first and second grips of the present invention, showing the combined structure.

[0018] Figure 3 is an enlarged view of the structure of Part 2A of the system diagram.

[0019] Figure 4 is an exploded perspective view of the clamp structure of the present invention.

[0020] Figure 5 is a plan view of the ventral side structure of the first handle of the present invention.

[0021] Figure 6 is a schematic diagram of the second grip of the present invention during operation.

[0022] Figure 7 is an enlarged view of the structure of Part 6B of the series.

[0023] Figure 8 is a schematic diagram showing the state of the clamp of the present invention when the jaws are positioned in the target workpiece.

[0024] Figure 9 is a schematic diagram of the state of the clamp of the present invention when the jaws of the clamp are engaged with the target workpiece and the second handle begins to operate.

[0025] Figure 10 is a schematic diagram of the state of the first grip during the operation of the second grip of the present invention.

[0026] Figure 11 is a schematic diagram of the state when the clamp of the present invention completes the clamping of the target workpiece. Implementation

[0027] To achieve the above-mentioned objectives, the present invention provides a preferred embodiment, which is described in detail below with reference to the accompanying drawings: A large-jaw universal pliers structure, as shown in Figures 1-5, is a clamp 10, comprising: a first handle 20, which extends from one end of a C-shaped gripping portion 21 to form a support head 22, and the other end is provided with a screw hole 23; the support head 22 has a side wall 220 on its ventral side, and a through-hole 221 is formed on the side wall 220; a shaft 24, which is a long rod 240 with a cross-section corresponding to the shape of the through-hole 221, passes through the through-hole 221, and is mounted on the support head 22, and the axis of the long rod 240 is defined as a working center line CE of the clamp 10. A limiting clamp 30 is located outside one side of the sidewall 220 of the support head 22, and is mounted on the shaft 24. It has an assembly part 31 with a plate-shaped body attached to the shaft 24. The assembly part 31 is located at one end above the workpiece centerline CE, away from the shaft 24, and extends to a limiting clamp arm 32. The limiting clamp arm 32 is a nearly inverted U-shaped arm with a first chuck 33 at its end. A movable clamp 40 is located on the other side of the sidewall 220 of the support head 22, corresponding to the assembly part 31 of the limiting clamp 30. It has a plate-shaped body identical to the assembly part 31 and on the same side as the shaft 24. A movable jaw head 41 is located above the working center line CE, away from the shaft 24, and extends to a movable jaw arm 42. At the corner of the end below the working center line CE, there is a pivot portion 43 pivotally connected to the support head 22 and a first pivot portion 44 away from the support head 22. The movable jaw arm 42, corresponding to the limiting jaw arm 32, is a nearly U-shaped arm with a second clamp 45 at its end. Furthermore, a latching portion 46 is provided between the pivot portion 43 and the first pivot portion 44 of the movable jaw head 41. An elastic element 60 (ideally a tension spring) is fixed at one end to the grip portion 21, and the other end... The connecting part 46 is used to pull the movable clamp 40 back to its original position after swinging; a second handle 70 is pivotally connected to the first pivot part 44 at one end of a gripping part 71 by a first pivot pin 72, and a second pivot pin 73 is provided at the other end a certain distance from the tail; a third pivot pin 74 is provided between the first pivot pin 72 and the second pivot pin 73; an unlocking member 80 is pivotally connected to the second pivot pin 73 at its middle part, with a push part 81 at one end of the pivoting position and an unlocking operation part 82 at the other end; a connecting rod 90 has an arcuate protrusion 91 opposite to the push part 81, with one end of the arcuate protrusion 91 pivotally connected to the third pivot pin 74, and the other end extending to the gripping part 21 to form a stop part 92; A screw 25 is screwed into the screw hole 23, one end of which abuts against the stop 92 on the grip 21, and the other end extends out of the screw hole 23, forming a rotating operating head 250;As shown in Figures 6 and 7, when the second chuck 45 of the clamp 10 is blocked or restricted (e.g., when it comes into contact with the target workpiece), the first handle 20 and the second handle 70 only need to grip each other closely to apply force. Initially, the first handle 20 will first deflect at an angle α (this angle α, as shown in Figures 3 and 7, is determined or set by the thickness of the sidewall 220 and / or the gap between the through-hole 221 and the shaft 24, ideally about 5 degrees), causing the through-hole 221 to clamp (lock) the shaft 24, thus preventing the support head 22 from sliding on the shaft 24. Later, during the force application process, the second handle 70 swings around the first shaft pin 72, and through the resistive support of the connecting rod 90, pushes the movable clamp 40 to rotate, causing the second chuck 70 of the movable clamp arm 42 to generate a clamping force towards the first chuck 33.

[0028] That is, as shown in Figure 8, when the clamp 10 is to clamp the target workpiece 11, the shaft 24 can be adjusted by sliding left and right on the support head 22 (i.e., the through shaft hole 221) of the first grip 20 (or the assembly part 31 of the limiting clamp 30 can be adjusted by assembling, fixing or limiting the position on the shaft 24), so that the first chuck 33 and the second chuck 45 are close to or touch the target workpiece 11; as shown in Figures 9 and 10, when the second grip 70 is moved towards the first grip 20 and the gripping part 71 is moved towards the holding part 21 to exert force, the stationary target workpiece 11 blocks the reaction force generated by the second chuck 45, causing the first grip 20 to deflect (see reference). Figure 6 shows that by making an angle α sway, the support head 22 can first clamp (lock) the shaft 24 through the through hole 221 when the second handle 70 is gripped (see Figures 3 and 7), thus fixing the position of the pivot part 43. In this way, as shown in Figure 11, the force output process of the gripping operation of the second handle 70 (gripping part 71) is continuously exerted. By the limiting support of the second handle 70 by the connecting rod 90, the slight swaying motion made by the first shaft pin 72 with the pivot part 43 as the center allows the movable clamp arm 42 to complete the clamping action on the target workpiece 11 through the second clamp 45 under the condition that the limiting clamp arm 32 and the first chuck 33 are fixed.

[0029] As shown in Figures 2 and 11, the overall structure of the clamp 10 allows for easy adjustment of the jaw 50 between the first chuck 33 and the second chuck 45 over a long distance within the length of the shaft 24 to accommodate the clamping of ultra-large target workpieces 11, thereby significantly improving or expanding the clamping capability of the clamp 0 for the target workpiece 11.

[0030] According to the above embodiments, preferably, as shown in Figures 2 and 5, the through hole 221 of the support head 22 of the first grip 20 is a flat elongated hole, and the shaft 24, with a cross-section relative to the through hole 221, is a long rod 240 of a ruler-shaped flat iron that can freely slide in and out of the through hole 221; by forming a large area of ​​surface contact between the shaft 24 and the movable clamp head 41 of the movable clamp 40, as shown in Figures 8-11, the swinging motion of the movable clamp 40 can be limited or guided by the surface of the shaft 24 during the swinging motion of the movable clamp head 41, reducing swaying or deflection.

[0031] According to the above embodiment, preferably as shown in Figure 2, the support head 22 of the first grip 20 is fixed with at least one stop post 26 close to the shaft 24 above and below the working center line CE (ideally, a stop post 26 is provided on the upper and lower sides of the shaft 24 respectively). By having at least one stop post 26 above and below the working center line CE of the support head 22 to assist the shaft hole 221 in supporting the shaft 24, in addition to increasing the resistance to hole deformation of the shaft hole 221, it can also reduce or avoid excessive horizontal tilting of the two ends of the shaft 24 when it passes through the shaft hole 221.

[0032] According to the above embodiment, optionally, as shown in FIG2, the assembly part 31 of the limiting clamp 30 is fixed outside the non-movable clamp 40 end on one side of the side wall 220 of the support head 22 (not shown, for example, it can be fixed by screw locking) on ​​the shaft 24; by fixing the assembly part 31 of the limiting clamp 30 on the shaft 24, the relationship between the first chuck 33 (including the limiting clamp arm 32) and the shaft 24 is fixed, so that the clamp 10 can slide left and right on the shaft hole 221 of the support head 22 (not shown) through the shaft 24, and adjust the size of the jaw 50 of the clamp 10.

[0033] According to the above embodiments, preferably as shown in Figures 2, 3, and 4, the assembly part 31 of the limiting clamp 30 abuts against the shaft 24. The assembly part 31 is formed with a cross-connector 310. A set of shaft holes 311 are formed on the cross-sectional shape of the shaft 24, and the shaft 24 passes through the set of shaft holes 311 to assemble the assembly part 31 onto the shaft 24. As shown in Figures 6 and 7, when the first chuck 33 of the limiting clamp 30 is blocked, the assembly part 31 slightly deflects by an angle β, which can cause the set of shaft holes 311 to clamp (lock) the shaft 24, preventing it from sliding to the distal end. The fixed function of the clamp 10, as shown in Figure 8, allows the clamp 10 to slide and shift from the assembly position of the assembly part 31 of the limiting clamp 30 on the shaft 24, adjusting the size of the jaws 50 of the clamp 10 to match the target workpiece 11; as shown in Figure 4, and a support plate 312 is formed at the end of the cross-connector 310 of the assembly part 31. By having the support plate 312 and the assembly part 31 jointly abut against both sides of the shaft 24, as shown in Figures 1 and 11, when the first chuck 33 is used to clamp the target workpiece 11, the clamping of the support plate against the shaft 24 can reduce the swaying of the limiting clamp arm 32 when subjected to force; as shown in Figures 2 and 4, furthermore, The first chuck 33 is provided at the end of the limiting clamp arm 32 extending from one end of the assembly part 31. The first chuck 33 is approximately T-shaped and has a first clamping surface 330. The opposite ends of the first clamping surface 330 are pivotally mounted on the end of the limiting clamp arm 32 by a first pivot 331. The first chuck 33 allows swinging on the end of the limiting clamp arm 32, as shown in Figures 8 and 9. Even if the assembly part 31 swings to clamp the shaft 24, the first clamping surface 330 of the first chuck 33 can still be held flat on the target workpiece 11.

[0034] According to the above embodiment, preferably as shown in Figure 2, the movable clamp arm 42 of the movable clamp 40 is provided with a second chuck 45. The second chuck 45 is approximately T-shaped (equivalent to the structure of the first chuck 33 in Figure 4) and has a second clamping surface 450. The opposite ends of the second clamping surface 450 are pivotally mounted on the end of the movable clamp arm 42 by a second pivot 451. The second chuck 45 allows the movable clamp arm 42 to swing at the end of the movable clamp arm 42, as shown in Figures 8-11, so that the movable clamp arm 42 swings toward the target workpiece 11. The second clamping surface 450 of the second chuck 45 can naturally or automatically adjust to fit against the target workpiece 11, and solidly transmit the clamping force to the target workpiece 11.

[0035] According to the above embodiments, optionally, as shown in Figures 2 and 4, at least one end (ideally both ends) of the long rod body 240 of the shaft 24 is provided with a limiting member 241 (which may be a pin) protruding from the radial surface of the long rod body 240, so that the limiting member 241 cannot pass through the through hole 221, thereby restricting the shaft 24 from detaching from the support head 22.

[0036] The above description is illustrative only and not restrictive for the purposes of this invention. Those skilled in the art will understand that many modifications, variations or equivalents can be made without departing from the spirit and scope defined in the appended specification, and all such modifications, variations or equivalents will fall within the protection scope of this invention.

[0037] 10: Pliers

[0038] CE: Centerline of Work

[0039] 11: Target workpiece

[0040] 20: First grip

[0041] 21: Grip section

[0042] 22: Support the head

[0043] 220: Sidewall

[0044] 221: Through-shaft hole

[0045] 23: Screw hole

[0046] 24: Shaft

[0047] 240: Long rod

[0048] 241: Limited to removing parts

[0049] 25: Screw

[0050] 250: Rotate the operating head

[0051] 26: Bollard

[0052] 30: Limited clamps

[0053] 31: Assembly Department

[0054] 310: bridging body

[0055] 311: Sleeve hole

[0056] 312: Backrest

[0057] 32: Limited clamp arm

[0058] 33: First clamp

[0059] 330: First clamping surface

[0060] 331: First Pivot

[0061] 40: Moving clamps

[0062] 41: Movable pliers head

[0063] 42: Movable clamp arm

[0064] 43:Central Ministry

[0065] 44: First pivot section

[0066] 45: Second clamp

[0067] 450: Second clamping surface

[0068] 451: Second Pivot

[0069] 46: Button pull section

[0070] 50: Jaws

[0071] 60: Elastic element

[0072] 70: Second grip

[0073] 71: Grabbing Department

[0074] 72: First pivot pin

[0075] 73: Second pivot pin

[0076] 74: Third pivot pin

[0077] 80: Unlocking Item

[0078] 81: Push / Push Section

[0079] 82: Unlock Operation Section

[0080] 90: Connecting rod

[0081] 91: Arc-shaped convex part

[0082] 92: Stopping part

Claims

1. A large-jaw universal pliers structure, comprising: A first grip extends from one end of a C-shaped grip portion to form a support head, and the other end has a screw hole; the ventral side of the support head has a sidewall with a through-hole; a shaft is a long rod with a cross-section corresponding to the through-hole, which passes through the through-hole and is mounted on the support head, with the axis of the long rod defined as a working center line of the clamp; a limiting clamp is located outside the sidewall of the support head, mounted on the shaft, having a side that abuts the shaft, and is assembled to limit the clamp. The assembly part on the rod has an end above the workpiece centerline extending away from the shaft, extending into a limiting clamp arm. This limiting clamp arm is a nearly inverted U-shaped arm with a first chuck at its end. A movable clamp is located on the other side of the support head's sidewall, corresponding to the assembly part of the limiting clamp, and has a movable clamp head on the same surface as the assembly part and adjacent to the shaft. The movable clamp head has an end above the work centerline extending away from the shaft, extending into a movable clamp arm, while the end below the work centerline... At the corner, there is a pivot part pivotally connected to the support head and a first pivot part away from the support head; the movable clamp arm, corresponding to the limiting clamp arm, is an arm body in a near-U shape, with a second clamp at the end; furthermore, a latching part is provided between the pivot part and the first pivot part of the movable clamp head; an elastic member, one end of which is fixed to the gripping part and the other end connected to the latching part, is used to pull the movable clamp arm back to its original position after swinging; a second handle is provided at one end of a gripping part with a first pivot pin pivotally connected to the first pivot part, and the other end... A second pivot pin is provided at a distance from the tail end, and a third pivot pin is provided between the first pivot pin and the second pivot pin; an unlocking member is pivotally connected to the second pivot pin at its middle part, with a push portion at one end of the pivot position and an unlocking operation portion at the other end; a connecting rod has an arcuate protrusion relative to the push portion, with one end of the arcuate protrusion pivotally connected to the third pivot pin and the other end extending to the grip portion to form a stop portion; a screw is screwed into the screw hole, with one end abutting the stop portion on the grip portion and the other end extending out of the screw hole to form a rotating operation head.

2. The large-jaw universal pliers structure as described in claim 1, wherein, The through hole of the support head of the first grip is a flat elongated hole, and the shaft, with a cross section relative to the shape of the through hole, is a long rod of a ruler-shaped flat iron that can slide freely in and out of the through hole.

3. The large-jaw universal pliers structure as described in claim 1, wherein, The support head of the first grip is fixed with at least one stop post near the shaft above and below the working center line.

4. The structure of the large-jaw universal pliers as described in claim 1, wherein, The assembly portion of the limiting clamp is fixed to the shaft outside the non-movable clamp end on one side of the sidewall of the support head.

5. The structure of the large-jaw universal pliers as described in claim 1, wherein, The assembly part of the limiting clamp abuts against the shaft. The assembly part is formed with a cross-connector. The cross-connector has a set of shaft holes that are open relative to the cross-sectional shape of the shaft. The shaft passes through the set of shaft holes to assemble the assembly part onto the shaft.

6. The structure of the large-jaw universal pliers as described in claim 5, wherein, The end of the bridging body of the assembly part has a support plate.

7. The structure of the large-jaw universal pliers as described in claim 5, wherein, The first chuck is provided at the end of the limiting clamp arm extending from one end of the assembly part. The first chuck is approximately T-shaped and has a first clamping surface. The opposite ends of the first clamping surface are pivotally mounted on the end of the limiting clamp arm by a first pivot.

8. The structure of the large-jaw universal pliers as described in claim 1, wherein, The movable clamp arm of the movable clamp is provided with a second chuck. The second chuck is approximately T-shaped and has a second clamping surface. The opposite ends of the second clamping surface are pivotally mounted on the end of the movable clamp arm by a second pivot.

9. The structure of the large-jaw universal pliers as described in claim 1, wherein, At least one end of the long rod of the shaft has a release element that protrudes from the surface of the long rod in the radial direction.

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