EP0837754A1

EP0837754A1 - Vice-grip pliers

Info

Publication number: EP0837754A1
Application number: EP96925782A
Authority: EP
Inventors: Lucien Roger Grayo; Jean-Paul Zerkovitz
Original assignee: Facom SA
Current assignee: Facom SA
Priority date: 1995-07-13
Filing date: 1996-07-12
Publication date: 1998-04-29
Anticipated expiration: 2016-07-12
Also published as: DE69620183D1; WO1997002926A1; FR2736572A1; KR19990028958A; BR9609627A; ATE215000T1; ES2175114T3; JPH11509141A; AU6617496A; US6227080B1; EP0837754B1; MX9800351A; DE69620183T2; CN1061582C; CN1193295A; FR2736572B1

Abstract

Locking grips (1) designed so that their latch lock mechanism (8) cannot travel beyond a point of alignment of its three points but locks, slightly set back with respect to this alignment, by the snap-fastening of a relief (30) of a catch (28) borne by a lever (10) behind a tooth (19) of a front end of a link (13). The catch (28) forms a trigger (28A) which allows the locking grips to be opened in a controlled way after the lever (10) has been released.

Description

"Locking pliers". The present invention relates to a vice grip of the type described in the preamble of claim 1.

Locking pliers of this type make it possible to exert, for a long period of time, without operator intervention, a large clamping force on one object, or more frequently on two objects to be assembled.

To give the tool a stable clamping position, conventional toggle mechanisms are designed to slightly cross their alignment at the end of clamping, by playing on the elasticity of the parts. This results in a serious drawback: the loosening of the vice grip suddenly releases the elastic energy stored during tightening, which causes a shock, which can be violent and dangerous, in the operator's hand.

The object of the invention is to eliminate this drawback by providing a vise grip of simple and ergonomic design which the operator can open while controlling this opening. In particular, if the tightening was carried out with one hand, the operator can open the clamp with one hand.

To this end, it relates to a vise grip of the aforementioned type, characterized by the characterizing portion of claim 1. The vise grip according to the invention may include one or more of the characteristics described in claims 2 to 16 .

Exemplary embodiments of the invention will now be described with reference to the drawings annexed, on which:

- Figure 1 is a longitudinal sectional view of a vise grip according to the invention, in the maximum open position and adjusted to clamp an object of minimum thickness;

- Figure 2 is an external view corresponding to the fixed handle;

- Figure 3 is a view similar to Figure 1 showing the vise grip in the clamping position; - Figure 4 is a view similar to the

Figure 3 of a variant of the vise grip, in its clamping position of an object of thickness close to the maximum value;

- Figure 5 is a view similar to Figure 2 but corresponding to the setting of Figure 4;

- Figure 6 is an external view of a variant provided with an indicator of the degree of tightening;

- Figure 6A is a partial view of a variant; - Figures 7 to 9 are partial views illustrating the use of the tightening indicator of Figure 6;

- Figure 10 is a view similar to Figure 3, relating to another embodiment of the vise grip according to the invention; and

- Figure 11 is an exterior view of a variant of the vice grip of Figure 6.

The vice grip 1 shown in Figures 1 to 3, generally planar, consists of a fixed crew 2 and a mobile crew 3.

The fixed assembly 2 has a very elongated general S shape which has a distal or front end part 4 constituting a fixed jaw, a proximal or rear end part 5 roughly parallel to the part 4 and constituting a first handle or fixed handle, and an intermediate connecting part 5A. In the normal position of use shown, the jaw 4 is lower than the handle 5. The movable assembly 3 comprises a movable jaw

6 of generally triangular shape, the lower rear vertex of which is articulated at the root of the fixed jaw by a pivot 7, and a toggle mechanism 8 provided with an adjustment device 9. The toggle mechanism 8 comprises an actuating lever 10, the front end of which is articulated at the upper rear apex of the movable jaw by a pivot 11, and the rear end of which forms a second handle or movable handle 12, located under the fixed handle 5.

The mechanism 8 also comprises a connecting rod 13, the front end of which is articulated at an intermediate point of the lever 10 by a pivot 14, and the rear end of which carries a pivot 15. This pivot passes through oblong slots along the general axis of the handle 5, provided in the two wings of a yoke 16, which is part of the adjustment device 9. About halfway along the length, the connecting rod 13 has a protuberance 17 in a U shape, directed towards the handle 12, who trains at its base has a slot 18. At its front end, this connecting rod has a single hooking tooth 19, the front face of which forms an upper circular arc 19A centered at 14, a lower circular arc 19B of smaller radius, and a face radial 19C, facing down, connecting these two arcs. The face 19C, which constitutes the hooking face, is substantially radial relative to the pivot 14.

The adjusting device 9 comprises a nut 20 fixed in the handle 5, a screw 21 which passes through this nut, and an operating button 22. The front end of the screw passes freely through the core of the yoke 16 and, inside thereof, is equipped with a support head for the rear end of the connecting rod 8. The rear end of the screw 21 forms a square or a hexagon 23 received slidingly in a conjugate recess 24 of a sheath 25. The button 22 is fixed on this sheath so that an inner flange 26 of the handle 5 is trapped between this button and an outer flange 27 of the sheath 25. In this way, the button operation is rotatably mounted, but immobilized in translation, at the rear end of the handle 5.

The mechanism 8 also comprises a locking / unlocking finger 28 articulated on the lever 12 by a pivot 29 adjacent to the pivot 14. On its interior side, facing the handle 5, this finger has a recess delimited upwards by a upper triangular tooth 30, which forms a single hooking tooth, and downwards by a lower triangular abutment tooth 31. The upper edge 31A of the latter is radial relative to the pivot 29. Furthermore, at its front end, near the tooth 30, the finger 28 has a protuberance 32. In the example of Figures 1 to 3, the part of the finger which carries the teeth 30 and 31 and the protuberance 32 is constituted by a separate attached piece. For example, this piece can be made of metal and the rest of the finger of plastic. The mechanism 8 also comprises a multifunction spring 33. This spring comprises a helical rear part 34 hooked under tension to the connecting rod 13 near the pivot 15, then a rectilinear part 35 which extends, substantially along the general axis of the fixed handle 5, to the pivot 11, then a hairpin part 36 which surrounds this pivot for one and a half turns and presses on the protuberance 32 of the finger 28, while tending to rotate this finger clockwise around the pivot 29. The operation of the vise grips thus described is as follows.

At the start, the vice grip is in its maximum opening position shown in FIG. 1, in which the face 19C of the connecting rod is in abutment on the face 31A and the tooth of the finger 30 is in abutment on the face 19A of the connecting rod. This prohibits a greater relative spacing of the two handles. This grip is maintained by the support of the end 36 of the spring 33 and the tension of its part 34, which urges the movable jaw 6 at the opening. The rear part 28A of the finger 28 forms a trigger which projects slightly below the intermediate part of the lever 10.

In the represented state of the adjusting device 9, the screw 21 is advanced almost to the maximum. This is made visible, if there is no sheath covering this part, by the fact that the ends of the pivot 15 are guided in two longitudinal slots 37 (Figure 2) of the handle 5 and are almost at the front end of these lights. This adjustment corresponds to the tightening of an object 38 of minimum thickness, for example 1 mm thick, shown in FIG. 3.

To grasp the object 38, the operator raises, with his four fingers, the handle 12 to bring it closer to the handle 5 (direction F of FIG. 1), which is wedged in the palm of the hand. The angle 11-14-15 opens gradually, and the movable jaw 6 approaches the fixed jaw 4, stretching the part 34 of the spring 33, until pinching the object 38. Simultaneously, the tip of the tooth 19 approaches that of tooth 30, the contact of the tip of tooth 30 on the arch 19A and that of the tip of tooth 31 on the arch 19B being maintained permanently by the part 36 of the spring. During this entire movement, the finger 28 is locked relative to the lever 10, so that the trigger 28A also forms a gripping surface for the operator's index finger.

By continuing to bring the two handles closer together, the operator slightly increases the angle of the knee lever and causes the tooth to snap into place. behind tooth 19, as shown in FIG. 3. The upper face of tooth 30 is then substantially radial with respect to pivot 14, and the stresses due to tightening tend to open the angle formed by axis 29, the point of the tooth 30 and the axis 14. The tip of the tooth 30 then abuts on the surface 19B of the connecting rod and prevents such opening. The tool has then reached its stable clamping position, for which the angle 11-14-15 is slightly less than 180 °, and typically of the order of 170 to 175 °. In this position, the trigger projects more strongly under the lever 10. The snap can thus be felt by the operator's index finger.

The front end of the connecting rod 13 then biases the part 35 of the spring 33 towards the handle 5 (upwards in FIG. 3), so that this part 35 applies the teeth 19 and 30 against each other with a force roughly perpendicular to the line 11-15. If the operator continues to lift the handle 12, the lever 10 abuts on the protuberance 17 of the connecting rod 8 before the alignment of the points 11, 14 and 15 is reached. This ensures that this alignment is never exceeded. After the handle 12 has been released by the operator, the tool returns to its stable clamping position due to the action of the spring 33. Two types of adjustment of the device 9 can occur. For a relatively weak tightening, the snap 19-30 occurs before the closing of the slot 18 of the connecting rod, so that it is the longitudinal elasticity of the latter in compression, predetermined by the geometry of its U-shaped protuberance, which defines the degree of tightening. The latter varies only slightly over the entire corresponding adjustment range.

On the contrary, for a stronger tightening, corresponding to an increased advance of the screw 21, the slot

18 closes before the snap-fitting 19-30 takes place, which makes it possible to obtain considerably stronger tightening of the object 38.

To release the object 38, the operator grasps the vise grip, slightly brings the handles closer, until reaching the stop 10-17. With his index finger, he squeezes the trigger 28A, which releases the tooth 30 from the tooth 19, and he then releases the handle 12 to let the vice grip open itself. This opening is effected by the action of the part 35 of the spring 33, which pushes the midpoint 14 of the toggle joint, and of its part 34, which brings the ends of one to the other. The maximum opening is defined by the stop of the surfaces 19C of the connecting rod and 31A of the finger. Thus, the elastic energy stored during tightening is released while the operator tightens the vise grip strongly, which prevents any explosive reaction in his hand.

The operator, in particular conditions of accessibility of the parts to be clamped, can use the overturned pliers with the palm on the branch 12, two to four fingers on the branch 5 and the thumb on the trigger 28A.

There is shown in Figure 4 a variant which differs from the previous one only in the following points:

- The screw 21 is simply secured to the button 22, so that the latter is more or less distant from the rear end of the handle 5 according to the chosen setting; the spring 33 has been split into three springs, each fulfilling one of the functions described above: a spring 34, wound around the pivot 7, to separate the movable jaw from the fixed jaw; a leaf spring 35, fixed in the handle 5, to urge the front end of the connecting rod away from this handle in the clamping position; and a hairpin spring 36, surrounding the pivot 11, for urging the front end of the finger 28 towards that of the connecting rod;

- the finger 28 is in one piece; and

- The connecting rod 13 is rigid, that is to say that the slot 18 is eliminated.

The operation of this variant is the same as previously, except that, due to the rigidity of the connecting rod, there is no easy tightening range, unless, of course, creating flexibility on another live part of the clamp. Figure 4 shows the tool in its stable position for clamping an object 38 of maximum thickness (a few centimeters in practice). In this case, the screw 21 is almost completely unscrewed, that is to say until the pivot 15 is brought near the rear end. lights 37, as shown in Figure 5.

Figure 6 shows a variant of the vice grip of Figure 4 provided with an indicator of the clamping level. For this, the lever 10 has a protuberance 39 projecting towards the handle 5, pierced with an orifice 40. When the operator effortlessly approaches the handle 12 of the handle 5 and grasps the object 38 without exerting clamping notable, the protuberance 17 of the connecting rod appears more or less in the orifice 40, and this can be modified by turning the button 22 in one direction or the other: the more this orifice is free, the stronger the final tightening .

The observation of indicator 40-17 should only be made with the following two conditions met: - jaws 4 and 6 in contact with the part;

- very little effort on handles 5 and 12, just enough to fight against the spring and keep the jaws in contact with the part.

The indicator indicates, when it has not yet clamped workpiece, the degree of the clamping force that will be obtained after performing the clamping operation to get into the stable position of ^one ratchet tooth 19 and 30.

The orifice 40 can be produced on protuberances 39 located on both sides of the protuberance 17, so that the indicator is clearly visible on both sides of the clamp. These protuberances 39 then form the two openwork wings of a yoke receiving the protuberance 17. Thus the indicator can be viewed by a left-handed or a right-handed person. It can also be viewed when the pliers are used in the inverted position, with the thumb on the trigger. The example of Figures 6, 7, 8 and 9 shows a protrusion 17 of circular shape and an orifice of circular shape. Alternatively, the indicator may consist of a protrusion 17 and an orifice 40 of various shapes. Thus, another example is given in FIG. 6A, with different shapes and a marking 40A indicating the declining nature of the resulting voltage, as has been explained with reference to FIGS. 7, 8 and 9. By way of example, Figures 7 to 9 illustrate three cases, but we can obtain all the intermediate or extrapolated tightening by turning the screw 22 more or less:

- Figure 7: the orifice 40 is almost free, the final tightening will be strong;

- Figure 8: the orifice 40 is moderately closed by the protrusion 17, the final tightening will be average;

Figure 9: the orifice 40 is almost completely closed by the protrusion 17, the final tightening will be light.

Figure 10 shows the application of the invention to a vise grip whose general configuration is reversed compared to the previous one: the fixed jaw 4 is in the extension of the handle 5, and the movable jaw 6 is on the same side of the straight line connecting the pivots 7 and 15 as the lever 10. In addition, the screw 21 extends towards the front, in the handle 5, from the pivot 15 (possibly with the use of a yoke as above), and the nut 20 is a cylindrical knurl mounted for rotation, but immobilized in translation, approximately halfway down the fixed assembly 2. The thread between the screw 21 and the nut 20 can be single thread or double thread, as known per se.

The operation and the properties of this embodiment are analogous to what has been described above with reference to FIGS. 1 to 3.

The invention can be extended to any type of vise grip, such as that of FR-A-2 237 730.

It should be noted that, in each embodiment, the vice-grip can be stored in the closed state by simple bringing together of the handles, without having to maneuver the adjusting screw. Closing the clamp for storage is therefore done with one hand, while for conventional clamps it takes two hands, one to turn the adjusting screw and the other to close the clamp.

In addition, closing the clamp for storage is quicker - in a gesture - because there is no need to turn the adjusting screw.

Locking pliers in general, and clamps vises according to the invention in particular, can be made from cut sheets, punched, stamped, and then assembled. Provision is therefore most often made, in particular for the handles, of synthetic resin (plastic) sheaths to ensure comfort and ergonomics during tightening.

Locking pliers are often used to bring parts together and hold them for welding. In this case, there are projections of solder or slag still hot, which become encrusted in the plastic sheath; this causes rapid deterioration of the sheath, but above all can cause hand injuries during a subsequent operation.

The embodiment of Figure 11, on the contrary, uses molded aluminum or aluminum alloy sheaths:

- in which the weld projections do not become embedded;

- which do not deteriorate on contact with hot parts;

- which nevertheless remain quite light.

The upper sheath 41, fitted on the handle 5 until it connects with the intermediate part

5A, protects the mechanism (toggle, spring, teeth 19 and 30) up to the parts close to the jaws, laterally and on top of the tool.

The lower sheath 42, fitted on the handle 10, may, in addition, have reliefs projecting upwards which penetrate between the sheets of the handle 5 to perform functions such as:

- tightening indicator (orifice 40), on a fin 43;

- stop 44, cooperating with the connecting rod as before, to prevent crossing the alignment of the toggle joint during tightening.

As shown, the sheath 42 may have a hole 45 for hanging the tool.

Claims

CLAIMS 1 - Vise pliers (1), of the type comprising: a fixed assembly (2) of generally elongated shape which forms at one end a fixed handle (5) and at the other end a fixed jaw (4); a movable assembly (3) comprising on the one hand a movable jaw (6) mounted on the fixed jaw by means of a first pivot (7), and on the other hand an actuation lever (10) whose end front is articulated on the movable jaw (6) by a second pivot (11) and the rear end of which forms a movable handle (12); a spring (34) which tends to spread the jaws apart

(4, 6) from each other; and a toggle joint (8) comprising two elements, namely on the one hand a connecting rod (13) whose front end is articulated by a third pivot (14) on an intermediate point of the lever and which extends up to a rear support point (15) adjustable along the fixed handle, and on the other hand the part of said lever (10) which extends between the second and third pivots (11, 14), characterized in that: - the connecting rod (13) and the lever (10) comprise reciprocal abutment means (12, 17) which prevent crossing the alignment of the toggle joint (8) during tightening;

- The connecting rod (13) and the lever (10) have respective stable clamping reliefs (19, 30) adapted to come to grip in mutual engagement just before the stop means (12, 17) arrive in reciprocal contact. close;

- the tightening relief (19) of the connecting rod is carried by the front end of this connecting rod, while the tightening relief (30) of the lever is connected to a trigger (28A) for releasing the attachment of said reliefs (19, 30), this trigger (28A) being disposed within reach of the index finger of the operator who exerts a tightening on the movable handle (12).

2 - Vise pliers according to claim 1, characterized in that the trigger (28A) is mounted on said lever (10), in particular pivoting around a fourth pivot (29), so as to sink into said lever upon release of said attachment.

3 - Vise pliers according to claim 1 or 2, characterized in that the reliefs consist of two teeth (19, 30), the tooth (30) of the lever (10) being rigidly connected to a movable finger (28) of which a part (28A) forms said trigger for releasing the catch.

4 - Vise pliers according to claim 3, characterized in that the finger (28) is locked relative to said lever (10) in all the positions of the toggle other than the position for hooking the teeth (19, 30).

5 - Vise pliers according to claim 4, characterized in that said blocking of the finger (28) is obtained by pressing a part (31) of the finger on a surface (19A), in particular circular and centered on the third pivot (14), from the front end of the connecting rod (13).

6 - Locking pliers according to any one of Claims 3 to 5, characterized in that the finger (28) has a second relief (31) which, in cooperation with a surface (19C) of the front end of the connecting rod (13), in particular carried by the tooth (19 ) of this connecting rod, forms an opening stop for the vise grip.

7 - Vise pliers according to any one of claims 3 to 6, characterized in that the tooth (30) of the finger (28) is urged elastically towards that (19) of the connecting rod (13). 8 - Vise pliers according to any one of claims 3 to 7, characterized in that it comprises a spring (35) which, when the teeth (19, 30) are engaged, presses on an element (13) of the toggle joint (8) in particular at the level of said third pivot (14), roughly perpendicular to the direction of alignment of the toggle joint (8) and in the direction of the breaking thereof.

9 - Locking pliers according to any one of claims 3 to 8, characterized in that, in the hooking position, the retaining surfaces of the hooking teeth (19, 30) are oriented approximately radially by report to said third pivot (14).

10 - Vise pliers according to any one of claims 1 to 9, characterized in that it comprises means (34; 35) which, permanently, elastically bias the toggle mechanism (8) in the direction of its breakage .

11 - Vise pliers according to claim 8, 9 and 10 taken together, characterized in that the spring (35) is tensioned substantially between the two end points (11, 15) of the toggle joint (8) and is wound around the front point (11) thereof, the free end (36) of the spring extending to the finger (28) to urge the tooth (30) thereof towards the other tooth (19) . 12 - Vise pliers according to any one of claims 1 to 11, characterized in that one (13) of the two elements of the toggle joint (8) has a longitudinal elasticity of compression over a predetermined compression length. 13 - Vise pliers according to claim 12, characterized in that the abutment means (12, 17) comprise a protuberance (17) in U of the connecting rod (13) which gives it said longitudinal elasticity of compression. 14 - Vise pliers according to any one of claims 1 to 13, characterized in that the stop means (12, 17) comprise a protuberance (17) of the connecting rod (13) which, depending on the adjustment of said point d 'rear support (15), moves relative to an indicator (40) integral with the lever (10) to visually indicate the final degree of tightening when gripping the part to be clamped between the two jaws (4, 6) without applying clamping force.

15 - Vise pliers according to claim 14, characterized in that the indicator (40) is carried by a yoke located on both sides of the protuberance (17) and the two wings of which are perforated.

16 - Vise pliers according to any one of claims 1 to 15, characterized in that the handles (5, 12) are coated with sheaths of aluminum or aluminum alloy (41, 42).