ES3039582A1 - Self-adjusting parallel jaw tool (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

The aim is to automate a parallel-jaw pliers whose fixing piece slides in a toothed cavity. A connecting rod (15) is engaged by means of a projection (22) in a groove (16) of the handle. Its end (20) slides on the bed. The connecting rod receives a few moments produced by springs anchored in its ends. Initially, the movable handle rotates around the projection (22) of the connecting rod and its protuberance (13), housed in a groove of the jaw (11), moves it until it touches the piece to be gripped. Then, a vertical sliding of the protuberance (13) in the groove (11) raises the shaft (14) and the trigger (24a): Its teeth contact those of the bed. Finally, thanks to the sliding of the projection (22) of the connecting rod and its end (20), it is possible to continue rotating the handle, couple the teeth (36), and press the piece. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Self-adjusting parallel jaw tool

Technology sector

This is a versatile tool that replaces pliers, wrenches, and optionally, bolt cutters. Tightening nuts of various sizes is quick and easy, thanks to its automatic adjustment, allowing for one-handed operation. It competes with ratchet wrenches because there's no need to remove the wrench from the nut, rotate it 60°, and then re-fit it. (When tightening a nut and needing to return to the correct angle, simply release the pressure on the tool's arms, allowing the jaws to open and contour around the nut, which will remain stationary until the next tightening angle is reached.) It's also important to note that, unlike standard wrenches or adjustable wrenches, the tightening action isn't concentrated on the corners of the nuts; significant pressure is applied across the entire surface of both sides. This prevents the nuts from becoming rounded in some cases and the grip from failing when dealing with nuts with worn corners.

The advantages of the original tool (parallel jaws, which act with a force up to twelve times greater than that exerted by the operator) are combined with this realization the convenience and speed of use (it is not necessary to initially adjust the tool manually) and the operator always has his second hand available to manipulate the piece.

Changing the jaws takes only seconds and requires no tools, giving the tool great versatility. (The tool can be converted into shears by attaching a blade, or, using the appropriate jaw, it can firmly grip tubes up to 50 mm in diameter and extend the opening range to 80 mm).

Background of the invention

This tool is similar to the one published in patent ES 2064565 of 04/09/1989. The conceptual similarities lie in the fact that one of the jaws slides along guides on the main body of the tool, which contains the other jaw, and that one of the tool's handles rotates, when clamping is about to occur, on a movable axis that has been previously fixed, pushing the movable part to which the jaw belongs. In both cases, it is a parallel-jaw tool, in which the jaws, after approaching the workpiece, move slowly, exerting a large force.

The tool in question has been, and continues to be, highly successful in industry despite requiring prior manual manipulation of the shaft's approach before the handles are tightened. The innovation of the project presented here is that this manipulation is performed automatically, without conscious operator intervention (since the initial contact with the workpiece is made using the same movement that subsequently applies pressure to it).

The operation of these tools is based on the fact that the movable handle, at its end, moves a jaw. It rotates around an axis that has been previously immobilized, blocking its movement along a groove perpendicular to the jaw. This axis acts as a fixed fulcrum and transforms the assembly into a first-class lever that multiplies the operator's force by twelve or more.

One of the essential and distinguishing features of this project, compared to the aforementioned patent, is that initially, this axle is moved by the end of the movable handle along the groove. Once contact is established with the object to be grasped, before being locked in place, this axle allows a small movement approximately perpendicular to it. This movement engages the axle's locking mechanism, which will be called the trigger, transforming the axle into the fixed fulcrum of a first-class lever.

A suitable mechanism ensures that the magicians' squeeze performs four successive operations automatically:

- Rapid approximation of the jaw until it touches the piece.

- Movement of the shaft approximately perpendicular to the groove and contact between the teeth.

- Fitting of the trigger teeth with the teeth of the groove.

- Pressure and compression of the part if it is elastic.

There are numerous known mechanisms that can be applied. All of them automate plumber's pliers with non-parallel jaws, which would otherwise require manual jaw adjustment before use. Despite the apparent similarity of the tool in this project to current quick-approach pliers, there are significant differences that necessitate new designs. One key difference is that in the aforementioned tools, the movable handle and jaw form a single piece. This means that when force is applied to the workpiece, the handle's jaw rests against it, preventing the handle from descending and ensuring the trigger engages with the teeth of the jaw. This is not the case with the presented project, as the movable handle and sliding jaw are two separate pieces that only make contact on the lateral surface of the inverted U-shaped groove in the jaw.

Another important difference is that the tools mentioned produce a force at the end of their jaws about four times greater than that of the user, and in this project, this force is twelve times greater. This means that the jaw displacement is very small compared to that of the handles, and if an elastic material is pressed, the handles could close completely without achieving a proper grip on the workpiece.

Another problem is that in the process of approaching the piece to be grasped, and the engagement of the trigger teeth with those of the bed, a large part of the initial angle of the handles is used.

The tool that is intended to be automated appeared on the market many years ago, and currently, with its patent rights having expired, at least twelve of the largest tool manufacturers are producing it. Although its automation was attempted from the beginning, achieving it today would represent market leadership, but various difficulties have prevented the project from being successfully completed.

Below is a list of patents for automatic pliers, but obviously none of them have parallel jaws:

US005887495A dated March 30, 1999

US 4651598 dated 24 Mar 1887

ES 2166662 A 1 date 16 April 2002

US 5020399 dated 4 Jun 1991

US 5660089 date 26 Aug 1997

US 4662252 dated 5 May 1987

Despite the numerous options available for designing the movable handle's drive mechanism, with their necessary adaptations, a new design has been chosen that uses a connecting rod that slides simultaneously over both handles, thus halving the spring elongation. By moving further away from the yield point, the possibility of material fatigue is reduced, and the operator's effort is lessened, making handling more comfortable.

Explanation of the invention

The tool comprises four main parts, Fig. 1:

1) A piece Fig. 1a (1) which, being the largest part of the tool, will be called the bed and is made up of:

- a handle Fig. 1 to (2)

- a central zone comprising grooves Fig. 1a (5) and an elongated cavity with a smooth wall Fig. 1a (3) and another wall with teeth Fig. 1a (6).

- one of the jaws of the tool Fig. 1a (4).

2) A sliding jaw Fig. 1 to (7) formed by:

- a movable jaw Fig. 1 to (10)

- a central zone comprising protrusions Fig. 1a (8) that will be housed in the grooves Fig. 1a (5) of the bench.

- inverted U-shaped grooves Fig. 1a (11) opposite the jaw, which will house protrusions Fig. 1a (13) on the upper end of the movable handle Fig. 1a (12).

3) A movable handle Fig. 1a (12) with the head drilled to accommodate a shaft Fig. 1a (14), with protrusions Fig. 1a (13) at the ends whose edges will push the surfaces Fig. 1a (9) of the sliding jaw.

4) A connecting rod Fig. 1a (15) with two perpendicular projections near its ends, the projection at its upper end Fig. 1a (22) sliding in a groove Fig. 1a (16) located between the upper third and the middle of the movable handle, and the projection at its lower end Fig. 1a (19) abutting projections Fig. 1a (21) of the handle of the bed. According to the embodiment, this projection Fig. 1a (19) can slide on the wall of the handle of the bed, or the lower end of the connecting rod Fig. 1a (20) can slide on the inner wall Fig. 1b (17) of the handle of the bed.

At the lower end of the connecting rod Fig. 1 a (20) that protrudes from the projection Fig. 1(19) a spring acts Fig. 1 a (18) and Fig. 1 b (18) anchored to the bed which produces a torque that tends to rotate the connecting rod downwards.

At the upper end of the connecting rod that protrudes from the projection Fig. 1 a (22) a spring acts Fig. 1 a (23) and Fig. 1 b (23) anchored to the movable handle, whose torque tends to rotate the movable handle and, as a consequence, to open the jaws completely.

Other pieces include:

- A trigger Fig. 1a (24a) which in combination with the teeth Fig. 1a (6) of the bed form a ratchet system.

- Another second trigger Fig. 1a (25a) that shares the same axis and whose teeth are offset with respect to the first trigger.

- An axis Fig. 1a (14) on which the movable handle head Fig. 1a (12) and the triggers are articulated.

Functioning:

The tool performs the following four operations sequentially and automatically:

1. - Approaching the piece to be grasped (from Fig.2 to Fig.3):

Initially, due to the spring pretension Fig. 1a (18), the lower projection of the connecting rod Fig. 1a (19) touches the stops Fig. 1a (21) of the bed handle, making this projection a fixed axis. Considering the equilibrium of moments about this axis, it is observed that, to counteract the action of the spring, the moving handle must exert an upward force on the connecting rod. It follows that the connecting rod exerts a downward force on the moving handle: This force Fig. 2 (26) ensures, in this initial displacement, that the trigger teeth remain clear of the bed teeth.

The movable handle will rotate (Fig. 2(27)) around the lower end of its groove (Fig. 2(16)) in contact with the projection (Fig. 1a(22)) of the connecting rod, which has become a fixed axis with respect to the handle because the spring keeps it in contact with the lower part of the groove. This axis will have a small movement perpendicular to the connecting rod because the connecting rod will rotate slightly about its lower axis (Fig. 2(19)).

Fig. 3 shows the trigger teeth still separated Fig. 3 (28) and the displacement Fig. 3 (29) of the trigger axis that will occur next.

2. - Contact between teeth: (from Fig. 3 to Fig. 5):

When the jaw is immobilized by touching the workpiece, the protrusion Fig. 4 (13) of the handle can only slide along the small, inverted U-shaped groove of the sliding jaw Fig. 1a (11). The instantaneous center of rotation Fig. 4 (30) of the movable handle will be perpendicular to this groove and passing through the point of contact. Its position is determined by its intersection with the extension of the connecting rod, which acts as a crank (since in this phase its projections serve as axes). Consequently, the force Fig. 4 (32) exerted by the operator on the handle, thanks to the lever arm Fig. 4 (31), will cause it to rotate about this instantaneous center of rotation, and its protrusion Fig. 4 (13) will engage the inverted U-shaped groove of the jaw. This approximately vertical movement of the handle is made possible by a small rotation of the connecting rod about its lower axis, Fig. 4 (19).

The trigger shaft will rise and raise it, its teeth will make contact with the teeth of the groove Fig.5 (33).

Fig. 5 shows the following rotation Fig. 5 (34) in which the protrusion Fig. 4 (13) will act as a ball joint.

3. - Tooth engagement (from Fig. 5 to Fig. 6):

Figure 5 shows that the teeth are in contact (Fig. 5(33)), but not engaged. The bed, handle, and connecting rod form a rigid, articulated triangle. The angle formed by the handle and the bed can only change if the connecting rod's joints give way. This occurs when the force increases (Fig. 4(32)) and the springs (Fig. 1(18) and Fig. 1(23)) lengthen. The upper axis of the connecting rod will begin to rise (Fig. 6(35), moving along the slot in the handle, and the end of the connecting rod (Fig. 1(20)) will begin to descend, sliding on the inner face (Fig. 1(17)) of the handle on the bed. Consequently, the lower projection of the connecting rod will separate from the projection on the handle of the bed (Fig. 6(38)). The protrusion of the movable handle will act as a ball joint around which rotation occurs. This turn Fig.5 (34) pulls the trigger back until its teeth mesh with those in the slot Fig.6 (36).

The rotation that begins below around the trigger axis is shown in Fig. 6 (37).

4.- Grip and compression of the piece (from Fig.6 to Fig.7):

With the trigger locked, its axis is immobilized and the handle becomes a first-class lever (Fig. 7). Since the handle is twelve times larger than the lever arm of the protrusion, it follows that the force exerted by the operator at the end of the handle is multiplied by 12. (In traditional pliers, this ratio is usually 3 to 4).

Depending on the elasticity of the part to be grasped, the movable handle will make an imperceptible or relevant rotation, which will force the lower end of the connecting rod to continue sliding on the handle of the bench Fig. 7 (40) and the upper projection of the connecting rod to move through the groove of the handle Fig. 7 (41).

To release the workpiece, simply stop pressing the tool handles. However, if it is desired that the jaws open forcefully when the hand holding them is released, more leverage is applied to the spring (Fig. 1a, 23). The increased torque causes the tool handles to open, and consequently, the jaws to open completely.

In this tool, since the sliding jaw and the movable handle are two separate pieces, a circumstance that does not occur with the aforementioned automatic pliers, there is a risk, in the tightening process, of the handle descending and, consequently, the trigger disengaging.

In order to achieve a force component Fig. 8 (42) that tends to keep the movable handle raised, an angle of inclination with respect to the vertical is given to the inverted U-shaped groove of the jaw Fig. 8 (43).

Since the force in Fig. 8 (44) is a dozen times smaller than the force in Fig. 8 (45), it follows that the force in Fig. 8 (46) exerted by the axle on the handle joint is opposite and similar to the force exerted by the jaw on the handle protrusion in Fig. 8 (45). Consequently, the force in Fig. 9 (47) received by the trigger is similar to that exerted by the jaw on the handle in Fig. 8 (45).

The line of action of the force Fig.9 (47) acting on the trigger Fig.9 (49a) is separated from the tip of the trigger tooth by a distance Fig.9 (48). If no other forces acted, a torque would be produced and the trigger would rotate Fig.10(49b), unable to perform its function.

This problem decreases by increasing the angle Fig.8(43) of inclination of the jaw slot, but geometric considerations prevent this increase.

The difficulty is resolved by using a trigger Fig. 11(50), with two appendages located on each side of its articulation. At one end are the teeth Fig. 10(52), and at the other, a circular surface is formed Fig. 10(51) whose diameter is similar to the width of the slot in the machine bed. This appendage has two purposes:

1. - Ensures that the trigger does not rotate when working because the lower part of the appendage Fig.11 (53) receives a force from the bed. Fig.11 (54).

2. - The upper part of the appendage Fig. 12 (55) that touches the teeth, rotates the trigger Fig. 12 (56) when its axis moves approximately perpendicular to the groove, amplifying the movement of the opposite end Fig. 12 (57) where the teeth are located.

Brief description of the drawings

Accompanying this description as an integral part is a set of drawings which, for illustrative purposes only and not as a limitation, depict the following:

Figure 1a. - Shows the project as a whole.

Figure 1b.- Shows the fixings of the connecting rod springs and their possible sliding along the wall (17) and the projection (22) being able to travel along the groove (16).

Figure 2.- Shows the force (26) produced by the connecting rod on the movable handle.

Figure 3.- Shows the sliding jaw in contact with the piece to be grasped, and the subsequent movement of the movable handle (29).

Figure 4.- Shows the instantaneous center of rotation (30) that determines the movement of the handle, and that will produce the contact of the teeth (from Fig.3 to Fig.5).

Figure 5.- Shows the trigger and bed teeth touching but not locked (33) and shows the rotation (34) that will follow.

Figure 6.- Shows the teeth touching and meshing (36), the sliding of the connecting rod protrusions (35) and (38) and the next rotation (37) that will occur.

Figure 7.- Shows the tool compressing the part.

Figure 8.- Shows the inclination of the sliding jaw slot (43) and the forces that appear on the movable handle.

Figure 9.- Shows the force exerted by the trigger shaft (47), separated by a distance (48) from the tip of the trigger tooth (49a).

Figure 10.- Shows the trigger rotation (49b) that would occur if only the axle force acted on it.

Figure 11.- Shows the trigger (50) with a circular appendage (51) opposite the teeth and how the bed produces a force (54) that prevents its rotation.

Figure 12.- Shows how the upper surface (55) of the appendage makes it a ball joint and how the resulting rotation amplifies the movement (57) of the teeth.

Figure 13 shows two identical thin triggers (24a) and (24b) whose teeth are offset from the teeth of the central trigger (25a). Notches (58) and (59) are visible on the upper surface opposite the teeth.

Figure 14.- Shows an alternative configuration to the triggers (24a) (24b) and (25a).

Figure 15.- Shows another alternative configuration of the triggers (using only two triggers of the same thickness).

Figure 16.- The left column shows the large trigger (25a) engaged and the small trigger (24a) with its teeth offset, mounted on the same axis, but not engaged. (Note the need for the notches (58) to allow positioning). The right column shows how the triggers exchange roles when slightly displaced.

Figure 17 shows how the protrusion (19) of the connecting rod is separated (60) and the spring (18) is dislodged (61) in order to rotate (62) the movable handle sufficiently to remove the jaw. Figure 18 shows how a stop (63) attached to the movable handle limits the opening of the tool (65), and how moving this stop allows for a greater opening. It is shown how to make this stop adjustable by incorporating a screw (67).

Figure 19.- Shows another embodiment of the tool by replacing the sliding connecting rod with a compressible crank (70).

Figure 20.- Shows another embodiment of the tool replacing the sliding connecting rod with two cranks, the movement of the crank on the bed being limited by a stop (76).

Figures 21 and 22.- Show some constructive variations of realization 1.

PREFERRED EMBODIMENT OF INVENTION No. 1

The tool in Fig. 1a consists of a bed made up of a handle, a jaw, and a central area with grooves in Fig. 1a (5) and a cavity with a toothed upper wall in Fig. 1a (6). The projections in Fig. 1a (8) of a sliding jaw, which has inverted U-shaped grooves inclined at 20° to the vertical in Fig. 8 (43), fit into the grooves. The protrusions in Fig. 1a (13) of a movable handle in Fig. 1a (12), whose axis in Fig. 1a (14) passes through the cavity of the bed, fit into these grooves.

A connecting rod Fig. 1a (15) consists of a projection Fig. 1a (22) threaded into a groove located approximately in the upper third of the movable handle. The other end of this connecting rod rests on the inner face Fig. 1b (17) of the handle, which is part of the bed. A pre-extended spring Fig. 1a (18), anchored to the bed, acts on this end. The lower bend of this connecting rod consists of a projection Fig. 1a (19) formed by a shaft that contacts stops Fig. 1a (21) on the bed. This arrangement allows the end of the connecting rod to be separated from the bed wall Fig. 17 (60), the spring Fig. 1a (18) to be dislodged Fig. 17 (61), and the movable handle to be rotated through a large angle Fig. 17 (62) in order to remove the sliding jaw. A pre-tensioned spring is mounted Fig. 1a (23) anchored between the upper end of the connecting rod that protrudes from the projection Fig. 1a (22), and the movable handle, achieving:

- Ensure that during the approach operation the protrusion Fig. 1 (22) of the connecting rod does not detach from the lower edge of the groove Fig. 1 (16).

- That the torque produced by the spring tends to separate the tool handles completely when the hand pressure is loosened.

This position, with the handle angle excessively open, makes handling the tool awkward. To limit this opening, a stop attached to the movable handle (Fig. 18(63)) is used. This stop limits the angle when it reduces its distance from the bed (Fig. 18(64)) and makes contact with the bed (Fig. 18(65). If a wider opening is needed, the stop is moved by pressing it (Fig. 18(66)), allowing the movable jaw to retract to its maximum opening. (This operation forces the connecting rod end to slide downwards on the handle of the bed (Fig. 18(68)) and causes a displacement of the connecting rod's upper projection (Fig. 18(69)). Optionally, to regulate the jaw opening limit, a screw (Fig. 18(67) is mounted, which acts as an adjustable stop.

- In order to reduce the angle (Fig. 6, 39) used in the tooth engagement operation, from Fig. 5 to Fig. 6 (whose value, in this embodiment, can reach 17°), three triggers (Fig. 13, 25a), Fig. 13, 24a, and Fig. 13, 24b) with offset teeth are mounted. The outer triggers (Fig. 13, 24a, and Fig. 13, 24b) are identical and can be replaced by a single one (Fig. 15) if symmetry of forces is not required. The large trigger (25a) is shown engaged in the left column of Fig. 16, along with one of the small triggers (24a), which, despite being mounted on the same axis and not engaged, is positioned without interfering with the teeth of the bed thanks to notches (Fig. 16, 58).

When the shaft is displaced by half a tooth, a situation represented in the right-hand column of Fig. 16, the triggers reverse their roles. Now the trigger (25a) is slightly rotated, not engaged, but is positioned thanks to its notches (59) in Fig. 16, and the small trigger (24a) engages.

Optionally, the lower perpendicular projection of the connecting rod Fig. 1a (19) can rest on the wall of the bed handle Fig. 21 (81), or be threaded into a groove produced in the bed handle Fig. 22 (83). In these cases, contact of the lower end of the connecting rod with the bed wall is eliminated.

Optionally, the perpendicular upper projection of the connecting rod Fig. 1a (22) can slide into the handle wall Fig. 21 (82), dispensing with the groove Fig. 1a (16).

PREFERRED EMBODIMENT OF INVENTION No. 2

Embodiment number 2 is similar, with the sole exception that the connecting rod is replaced by a piston and cylinder assembly Fig. 19 (70) housing a pre-compressed spring Fig. 19 (72). The assembly behaves as a rigid link unless an axial force exceeding the spring's compression is applied. If this force is exceeded, the spring yields Fig. 19 (74) and the movable handle rotates Fig. 19 (73).

PREFERRED EMBODIMENT OF INVENTION No. 3

In this embodiment (Fig. 20), the crank (Fig. 20(75)) is subjected to a torque produced by a spring housed in the handle of the bed, which tends to raise it, forcing it to touch the stop (Fig. 20(76)). This makes its end, during the approach to the workpiece, a fixed point (Fig. 20(77)). Once contact is established and the force on the handle is increased, the spring will yield, the crank will lower (Fig. 20(78)), separate from the stop (Fig. 20(79)), and allow the movable handle to rotate (Fig. 20(80)).

Claims (13)

1. Self-adjusting parallel jaw tool, comprising, - a bench (1) consisting of a handle (2), a clamp (4), grooves (5), an elongated horizontal cavity (3) parallel to the grooves, with a toothed upper edge (6). - a jaw that slides relative to the bed (7) thanks to projections (8) that fit into grooves (5), which consists of a second jaw (10) and an inverted U-shaped groove (11) opposite the jaw, with support surfaces (9). - a movable handle (12) with a drill in the upper area through which a shaft (14) passes and which has protrusions (13) that fit into the slot of the sliding jaw and remain in contact with its support surfaces (9). - a trigger (24a), coaxial with the axis of the movable handle (14), the trigger joint being located between its extremities, its teeth being placed in one of these (52), and the opposite extremity being formed by sections of circular profile (53), (55) that fit between the floor (3) of the elongated cavity of the bench and its toothed roof (6). and characterized, - because the trigger pivots on the end opposite its teeth (56) when its axis is subjected to a movement with a component perpendicular to the elongated cavity of the bench, this movement being produced by the movable handle whose upper protrusion (13), housed in the slot (11) of the jaw, slides over it. 2. Self-adjusting parallel jaw tool according to claim 1 characterized in that it has a second trigger (25a), coaxial with the first, the teeth of which are offset with respect to the teeth of the first (24a), the two triggers having notches at the ends opposite the teeth (58) and (59) which allow, when one of them is properly engaged, the other to be positioned slightly rotated, without interfering with the teeth of the bed. 3. Self-adjusting parallel jaw tool according to any of the preceding claims, characterized in that it has a connecting rod with perpendicular projections near its ends, the projection of the upper end (22) being threaded into a groove (16) made in the movable handle, and characterized in that the projection of the lower end (19) is immobilized by hitting stops (21) belonging to the handle of the bed. 4. Self-adjusting parallel jaw tool according to claim 3 characterized in that the groove (16) made in the movable handle is replaced by the upper wall of the movable handle (82) on which the upper projection of the connecting rod (22) slides. 5. Self-adjusting parallel jaw tool according to claim 3 characterized in that the lower end of the connecting rod (20) is in contact with, and slides on, the inner wall of the handle of the bed (17). 6. Self-adjusting parallel jaw tool according to claim 5 characterized in that the contact of the lower end of the connecting rod is replaced by threading its lower projection (19) into a groove made in the handle of the bed (83). 7. Self-adjusting parallel jaw tool according to claim 3 characterized in that it has a spring anchored at the upper end of the connecting rod and the movable handle, producing a torque and allowing, when expanded, the projection of the connecting rod (22) to move along the groove (16), and in that it has another spring anchored at the lower end of the connecting rod and the bed, producing a torque and allowing, when expanded, the lower projection (19) to descend. 8. Self-adjusting parallel jaw tool according to the preceding claims characterized in that the kinematics are simplified by reducing one of the grooves (16) or (83) to a point, converting it into a joint. 9. Self-adjusting parallel jaw tool according to the preceding claims, characterized in that a projection (63) belonging to the movable handle is used to limit the opening of the tool, achieving the crossing of said limit by applying a force (66) on the projection, displacing it. 10. Self-adjusting parallel jaw tool according to the preceding claims, characterized in that the arrangement of the bed stops and the handle groove are designed with the appropriate geometry that allows separating (60) the connecting rod protrusion, dislodging (61) the spring and turning (62) the movable handle sufficiently to disassemble the sliding jaw. 11. Self-adjusting parallel jaw tool according to claim 102 characterized in that the connecting rod is replaced by a compressible crank (72) comprising a telescopic system with a pre-compressed spring. 12. Self-adjusting parallel jaw tool according to claim 102 characterized in that the connecting rod is replaced by two cranks subjected to torques and one of them (75) is initially blocked by a stop (76). 13. Self-adjusting parallel jaw tool according to the preceding claims, characterized in that the slot of the sliding jaw (11) in which the handle protrusion is housed, is inclined (43) with respect to the perpendicular with its projections (8) in the direction of the bed clamp.