Arc-shaped rack type labor-saving wire cutting pliers

Abstract

This invention belongs to the technical field of manual hardware tools, specifically relating to an arc-shaped rack and pinion type labor-saving wire cutter. It replaces the direct bolt connection of the prior art with a movable gear pin and gear groove, allowing the gear pin to engage and move within the gear groove. The gear groove is arc-shaped, conforming to the movement trajectory of the wire cutter arm, resulting in smoother and more fluid operation. This invention features a compact and small structure, safe and convenient operation, low cost, simple processing and assembly, high production efficiency, and provides a sharp and quick cut with significant labor-saving effects.

Description

Technical Field

[0001] This invention belongs to the field of manual hardware tools technology, specifically relating to an arc-shaped rack and pinion type labor-saving wire cutter. Background Technology

[0002] Currently, commercially available wire cutters typically consist of left and right blades, cover plates, fixing bolts, nuts, left and right connecting arms, steel pipes, and handles. The left and right blades are fastened together by bolts through two cover plates, and the left and right connecting arms are also bolted together. The blades and connecting arms are further bolted together, and two steel pipes are connected to the connecting arms, each with a handle attached to its lower end. During operation, the two handles, steel pipes, and connecting arms are opened, causing the blades to open. The workpiece to be cut is placed between the blades, and then the handles, steel pipes, and connecting arms are closed, causing the blades to close and the workpiece to be cut. When traditional wire cutters cut workpieces with high hardness or large diameter, a large cutting force is required. Because the opening angle and the power arm remain constant when the two handles, steel pipes, and connecting arms are open, even greater force is needed to overcome the resistance of the workpiece. This results in high intensity, time-consuming, and labor-intensive work over extended periods. Summary of the Invention

[0003] To address the aforementioned problems, this invention provides an arc-shaped rack and pinion type labor-saving wire cutter. It replaces the direct bolt connection in the prior art with a movable gear pin and gear groove, allowing the gear pin to engage and move within the gear groove. The gear groove is arc-shaped, conforming to the movement trajectory of the wire cutter arm, resulting in smoother and more fluid operation. This invention features a compact and small structure, safe and convenient operation, low cost, simple processing and assembly, high production efficiency, and provides a fast, sharp, and labor-saving effect.

[0004] The solution provided by this invention is as follows:

[0005] An arc-shaped rack and pinion type labor-saving wire cutter includes two symmetrically matched blades, with a pressure plate symmetrically mounted in the middle of the two blades. The left and right sides of the pressure plate are movably connected to the two blades respectively. It also includes a first connecting arm and a second connecting arm. The front ends of the first connecting arm and the second connecting arm are movably connected to the two blades respectively. The front end of the first connecting arm is also provided with a gear groove, and the front end of the second connecting arm is provided with a gear pin. The first connecting arm and the second connecting arm are movably connected to the gear pin through the gear groove, and the gear pin can move within the gear groove.

[0006] The first and second connecting arms are each connected to two blades via pins at their front ends, allowing the blades to rotate around the first / second connecting arm. When force is applied, the gear shaft acts as a fulcrum, transmitting the force applied to the first / second connecting arm to the pin at the end of the blade. Then, using the connecting pin between the pressure plate and the blade as a fulcrum, the force is transmitted to the cutting edge at the tip of the blade. This two-stage lever system completes the force transmission and the shearing action.

[0007] In this invention, the gear groove is arc-shaped, with the center being the connection point between the first connecting arm and the blade. The arc-shaped gear groove can better fit the movement trajectory of the first connecting arm. During the opening and closing action of the wire cutter, the movement of the gear pin in the gear groove is smoother. At the same time, the arc shape is also more convenient for the stamping and forming of materials during production.

[0008] Even better, the circle containing the gear groove is concentric with the movement trajectory of the first connecting arm during the opening / closing process, so that the gear groove can completely fit the movement trajectory of the first connecting arm. There will be no resistance due to the angular deviation between the movement direction of the gear groove and the first connecting arm during the opening and closing process, making the movement of the gear pin in the gear groove smoother.

[0009] This invention replaces the direct bolt connection in the prior art with a movable gear pin and gear groove. This allows the gear pin to engage and move within the gear groove, so that when the blade is at its maximum opening angle (i.e., when the first and second connecting arms are at their maximum separation angle), the gear pin moves to the farthest end of the gear groove. This increases the lever arm when the hand applies force, generating a larger torque for the same amount of force, thus achieving a labor-saving effect. Simultaneously, due to the engagement of the gear pin and gear groove, the gear pin can move within the gear groove, causing the lever arm to constantly change during the shearing process, better matching the changes in the force applied by the hand. When the blade is fully closed and the shearing is complete, the gear pin moves to the closest end of the gear groove.

[0010] The gear groove has a rack on one side and no rack on the other side; the gear pin is tightly engaged with the rack, and the absence of a rack on the other side makes the movement smoother and reduces resistance.

[0011] In the gear groove used in this invention, the number of teeth on the rack is 10-15, and correspondingly, the number of teeth on the gear pin is also 10-15, which makes the gear pin move more smoothly on the rack and reduces jerking; when the first connecting arm and the second connecting arm are opened to the maximum angle, the angle between the first connecting arm and the second connecting arm is 160°-170°, which has a good labor-saving effect and is convenient for applying force.

[0012] Even better, the rear ends of both the first and second connecting arms are connected to handles for easy gripping and force application.

[0013] The force-saving effect of the present invention is analyzed below:

[0014] Compared to traditional, standard wire cutters:

[0015] First level of leverage:

[0016] Taking the tail of the wire cutters as the force input point, the pin connecting the middle handle as the fulcrum, and the connecting shaft between the handle and the blade as the force output point, let the input force applied at the tail be Fa, the distance from the tail force application point to the middle pin be the input lever arm La, the distance from the middle pin to the connecting shaft between the blade and the handle be the output lever arm Lc, and the output force at the connecting shaft be Fc. Then:

[0017] The input torque Ma is: Ma = Fa * La, and the output torque Mc is: Mc = Fc * Lc.

[0018] Ma = Mc.

[0019] Therefore, Fc = Fa * La / Lc;

[0020] Second level of leverage:

[0021] With the connecting shaft between the handle and the blade as the force input point, the connection point between the blade and the pressure plate as the fulcrum, and the tip of the blade as the force output point, let the input force be Fe, the connection point from the connecting shaft between the handle and the blade to the connection point between the blade and the pressure plate be the input lever arm Le, and the output force be Fg, and the output lever arm be Lg.

[0022] The angle between the direction of the input force Fe and the direction of the output force Fc at the same position as the first-stage lever is α;

[0023] Therefore, Fe = Fc * cosα = Fa * La * cosα / Lc, and the input torque Me = Fe * Le =

[0024] Fa*La*cosα*Le / Lc;

[0025] Output torque Mg=Fg*Lg,

[0026] Me = Mg, then

[0027] Output force Fg=Fa*La*cosα*Le / Lc*Lg,

[0028] Since La and Lc are both constant values, the force applied is the same throughout the entire process, resulting in no effort-saving effect.

[0029] The following is a force analysis of the present invention:

[0030] First level of leverage:

[0031] Taking the tail of the wire cutter as the force input point, the central gear pin as the fulcrum, and the connecting shaft between the connecting arm and the blade as the force output point, let the input force applied at the tail be Fb, the distance from the tail force application point to the central gear pin be the input force arm Lb, the distance from the central connecting pin to the connecting shaft between the blade and the handle be the output force arm Ld, and the output force at the connecting shaft be Fd. Then:

[0032] The input torque Mb is: Mb = Fb * Lb, and the output torque Md is: Md = Fd * Ld.

[0033] Mb = Md,

[0034] Therefore, Fd = Fb * Lb / Ld;

[0035] Second level of leverage:

[0036] With the connecting shaft between the handle and the blade as the force input point, the connection point between the blade and the pressure plate as the fulcrum, and the tip of the blade as the force output point, let the input force be Ff, the connection point from the connecting shaft between the handle and the blade to the connection point between the blade and the pressure plate be the input lever arm Lf, and the output force be Fh, and the output lever arm be Lh.

[0037] The angle between the direction of the input force Ff and the direction of the output force Fd at the same position as the first-stage lever is β;

[0038] Then, Ff=Fd*cosβ=Fb*La*cosβ / Ld, input moment Mf=Ff*Lf=Fb*Lb*cosβ

[0039] *Lf / Ld;

[0040] Output torque Mh = Fh * Lh,

[0041] If Mf = Mh, then

[0042] Output force Fh=Fb*Lb*cosβ*Lf / Ld*Lh,

[0043] Since Le = Lf and Lg = Lh are constant values, while Lb and Ld are constantly changing, and Ld decreases at a greater rate than Lb, the output force on the blade is greater when the input force is the same, i.e., Fb = Fa, i.e., Fh > Fg, thus achieving a labor-saving effect.

[0044] Compared with the prior art, the advantages of this invention are:

[0045] 1. It has a small and compact structure, is safe and convenient to use and operate, has low cost, is simple to process and assemble, has high production efficiency, and is fast, sharp, and labor-saving.

[0046] 2. The arc-shaped gear groove can better match the movement trajectory of the handle, and the movement of the gear pin in the gear groove is smoother during the opening and closing action of the wire cutter.

[0047] 3. The curved shape makes it easier to stamp and form materials during production, reducing production costs. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the structure of existing wire cutters.

[0049] Figure 2 This is a schematic diagram of the structure of this application (open state).

[0050] Figure 3 This is a schematic diagram of the structure of this application (closed state).

[0051] Figure 4 This is a schematic diagram of the first connecting arm structure.

[0052] Figure 5 This is a schematic diagram of the second connecting arm structure.

[0053] Figure 6 This is a schematic diagram of the gear pin structure.

[0054] In the diagram, 1 is the blade, 2 is the pressure plate, 3 is the pin, 4 is the second connecting arm, 5 is the handle, 6 is the gear pin, 7 is the gear groove, 8 is the first connecting arm, 9 is the limit screw, and 10 is the gear tooth. Detailed Implementation

[0055] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0056] As shown in the figure: An arc-shaped rack and pinion type labor-saving wire cutter includes two symmetrically fitted blades 1. The top of the blade 1 is the cutting edge. A pressure plate 2 is symmetrically mounted on the middle of the two blades 1. The left and right sides of the pressure plate 2 are connected to the two blades 1 by a combination of pins 3 and nuts, allowing the blades 1 to rotate around the pins 3. The two pins 3 are located on the same horizontal line, making the pressure plate 2 horizontal. The rotation of the two blades 1 around the pins 3 realizes the opening and closing action of the cutting edge.

[0057] The tail ends of the two blades 1 are connected to the outer ends of the first connecting arm 8 and the second connecting arm 4 respectively via pins 3, allowing the blades 1 to rotate around the outer ends of the first connecting arm 8 or the second connecting arm 4. A gear groove 7 is formed on the inner side of the top end of the first connecting arm 8. The gear groove 7 is an arc-shaped groove, with the connecting pin 3 between the first connecting arm 8 and the corresponding blade 1 at its center. When the first connecting arm 8 and the second connecting arm 4 are separated at their maximum angle, the included angle between the first connecting arm 8 and the second connecting arm 4 is 170°. The inner side of the gear groove 7 is a rack with 13 teeth, while the outer side is toothless to facilitate the movement of the gear pin 6.

[0058] A gear pin 6 is installed on the inner side of the top of the second connecting arm 4. The gear pin 6 is engaged inside the gear groove 7. One end of the gear pin 6 is threaded, and it connects the first connecting arm 8 and the second connecting arm 4 with a nut. The upper half of the gear pin 6 has 12 teeth 10, which mesh in the rack of the gear groove 7. The lower half has no teeth and engages with the outer side of the gear groove 7. When the first connecting arm 8 and the second connecting arm 4 are separated at their maximum angle, the gear pin 6 moves to the rightmost side of the gear groove 7. When the first connecting arm 8 and the second connecting arm 4 are closed to their minimum angle, the gear pin 6 moves to the leftmost side of the gear groove 7.

[0059] A limiting screw 9 is provided on the inner side of the middle position of the second connecting arm 4. When the first connecting arm 8 and the second connecting arm 4 are closed to their minimum position, the limiting screw 9 contacts the inner side of the first connecting arm 8 to limit the movement and prevent excessive force from damaging the blade.

[0060] The ends of both the first connecting arm 8 and the second connecting arm 4 are connected to rubber handles 5 for easy gripping and force application.

[0061] The method of using this invention is as follows:

[0062] In the closed state, the first connecting arm 8 and the second connecting arm 4 are closed to their minimum position, at which point the cutting edge is closed. During use, the first connecting arm 8 and the second connecting arm 4 are rotated outwards to their maximum position, causing the gear pin 6 to move from the left side of the gear groove 7 to the right side. The cutting edge is then open, allowing the bar stock to be placed inside. By forcefully closing the first connecting arm 8 and the second connecting arm 4, shearing can begin. During the shearing process, the gear pin 6 gradually moves along the rack from the far right to the far left of the gear groove 7, achieving a labor-saving effect. This labor-saving effect gradually changes, conforming to the rules of human force application, resulting in smooth operation.

Claims

1. A rack-and-pinion type labor-saving wire cutter, comprising two symmetrically fitted blades, with a pressure plate symmetrically mounted in the middle of the two blades, the left and right sides of the pressure plate being movably connected to the two blades respectively, and further comprising a first connecting arm and a second connecting arm, the front ends of the first connecting arm and the front ends of the second connecting arm being movably connected to the two blades respectively, the first connecting arm and the second connecting arm being rotatable around one end of the blades to complete the opening or closing action, characterized in that, The front end of the first connecting arm is provided with a gear groove, and the front end of the second connecting arm is provided with a gear pin. The first connecting arm and the second connecting arm are movably connected through the gear groove and the gear pin. The gear pin can move in the gear groove. The gear groove is arc-shaped, and the center of the circle is the connection point between the first connecting arm and the blade. When the first connecting arm and the second connecting arm open to their maximum angle, the gear pin moves to one end of the gear groove. When the first connecting arm and the second connecting arm close to their minimum angle, the gear pin moves to the other end of the gear groove. One side of the gear groove is a rack, and the other side is not a rack. The gear pin is in close engagement with the rack.

2. The arc-shaped rack and pinion type labor-saving wire cutter according to claim 1, characterized in that, The number of teeth on the rack matches the number of teeth on the gear pin.

3. The arc-shaped rack and pinion type labor-saving wire cutter according to claim 2, characterized in that, The rack has 10-15 teeth.

4. The arc-shaped rack and pinion type labor-saving wire cutter according to claim 1, characterized in that, When the first connecting arm and the second connecting arm are opened to their maximum angle, the angle between the first connecting arm and the second connecting arm is 160°-170°.

5. The arc-shaped rack and pinion type labor-saving wire cutter according to any one of claims 1-4, characterized in that, The circle containing the gear slot is concentric with the trajectory of the first connecting arm during the opening / closing process.

6. The arc-shaped rack and pinion type labor-saving wire cutter according to claim 1, characterized in that, The front ends of the first and second connecting arms are connected to two blades respectively via pins, and the two blades can rotate around the first and second connecting arms respectively.

7. The arc-shaped rack and pinion type labor-saving wire cutter according to claim 1, characterized in that, The rear ends of both the first and second connecting arms are connected to handles.

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