EP0962286B1 - Unidirectional strap wrench - Google Patents

Abstract

The strap wrench has an arm (6,7) and a strap (11). The strap is in the shape of a loop, with opposing sections (11A,11B) cooperating with two opposing zones (14) within the arm. Between the two zones a pad (15) is arranged, not connected to the strap, and including a cylindrical contact face (20). The pad is mounted so as to rock about a geometric axis (16). This axis is arranged so that the pad and strap combine to exert a force to drive the cylindrical object (2) in one direction (F2) and allow a sliding action of the strap on the object in the opposite direction (F1).

Description

• une partie formant manche,
• une sangle, notamment métallique, en forme de boucle, dont les deux brins opposés coopèrent avec deux zones solidaires du manche lorsque la sangle entoure étroitement ledit objet,
• le manche étant muni, entre lesdites deux zones, d'un patin d'appui sur ledit objet, ce patin d'appui n'étant pas lié à la sangle et présentant une face d'appui de forme générale cylindrique à génératrices perpendiculaires au plan général de la sangle.

The present invention relates to a strap wrench for unidirectional driving of an object of generally cylindrical shape, of the type comprising:

• a handle part,
• a strap, in particular a metal strap, in the form of a loop, the two opposite strands of which cooperate with two zones integral with the handle when the strap tightly surrounds the said object,
• the handle being provided, between said two zones, with a support pad on said object, this support pad not being connected to the strap and having a bearing surface of generally cylindrical shape with generatrices perpendicular to the plane general of the strap.

The invention applies in particular to the oil filter wrenches for motor vehicles, and in the following reference to this application.

Examples of such strap wrenches are described in the FR-A-1570027 and in the EP-A-0618045 in the name of the Claimant. A "ratchet effect" chain key is described in US Patent 2566108 .

In these known strap wrenches, the pad is rigidly secured to the handle. As a result, when the space available around the oil filter allows only a limited rotation of the key, the operator must perform repetitive maneuvers shortening / lengthening the useful length of the strap, by means of a wheel which is part of a screw-nut adjustment mechanism of the strap.

The invention aims to facilitate the use of strap keys in a particularly ergonomic manner.

For this purpose, the subject of the invention is a strap wrench of the aforementioned type, characterized by the characterizing part of claim 1.

The strap wrench according to the invention may comprise one or more of the features of claims 2 to 20, taken alone or in any technically possible combination thereof.

• la Figure 1 représente, en coupe longitudinale, une clé à sangle suivant l'invention, avec la sangle mise en position de façon lâche autour d'un filtre à huile à dévisser ;
• la Figure 2 est une vue analogue, après ajustement serré de la sangle autour du filtre à huile ;
• la Figure 3 est une vue analogue, pendant la première phase de dévissage du filtre;
• la Figure 4 est une vue analogue, pendant la phase subséquente de retour arrière de la clé ;
• la Figure 5 représente, en coupe longitudinale, un autre mode de réalisation de la clé à sangle suivant l'invention, pendant la première phase de dévissage ;
• la Figure 6 est une vue partielle en perspective éclatée d'un autre mode de réalisation de la clé à sangle suivant l'invention ;
• la Figure 7 est une vue extérieure, de face, de la clé à sangle de la Figure 5 ;
• la Figure 8 est une vue extérieure de côté du même outil ;
• les Figures 9 et 10 sont des vues extérieures d'une variante de la sangle de la figure 5, la sangle n'étant pas représentée;
• la Figure 11 est une vue en coupe longitudinale, prise dans le plan général de la sangle, d'une variante;
• la Figure 12 représente une variante du patin; et
• la Figure 13 représente à plus grande échelle le détail XIII de la Figure 12.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

• the Figure 1 represents, in longitudinal section, a strap wrench according to the invention, with the strap loosely positioned around an oil filter to be unscrewed;
• the Figure 2 is a similar view, after tight adjustment of the strap around the oil filter;
• the Figure 3 is a similar view during the first unscrewing phase of the filter;
• the Figure 4 is a similar view, during the subsequent backtracking phase of the key;
• the Figure 5 is a longitudinal section, another embodiment of the strap wrench according to the invention during the first phase of unscrewing;
• the Figure 6 is a fragmentary perspective exploded view of another embodiment of the strap wrench according to the invention;
• the Figure 7 is an external view, from the front, of the strap wrench of the Figure 5 ;
• the Figure 8 is an external side view of the same tool;
• the Figures 9 and 10 are external views of a variant of the strap of the figure 5 the strap is not shown;
• the Figure 11 is a longitudinal sectional view, taken in the general plane of the strap, of a variant;
• the Figure 12 represents a variant of the pad; and
• the Figure 13 represents on a larger scale detail XIII of the Figure 12 .

The strap wrench 1 shown on the Figures 1 to 4 is intended primarily to unscrew, and incidentally, by turning the key, to screw objects 2 of generally cylindrical shape, including oil filters, whose diameters may vary over a wide range, for example, in the embodiment shown from 66 to 96 mm.

To more conveniently describe the key 1, it will be assumed oriented as illustrated in the drawings, with the filter 2 horizontal axis O and located above the key.

• un corps rigide 3 qui comporte une embase 4 sur laquelle s'élève une chape 5 dont les ailes sont parallèles au plan du dessin.
• une tige filetée 6, qui peut être à filets multiples, dont l'extrémité inférieure porte un bouton d'actionnement moleté 7 tandis que son extrémité supérieure 8, lisse et de diamètre réduit, tourillonne dans un perçage central 9 de l'embase 4 en étant immobilisée en translation dans ce perçage, à la manière décrite dans le FR-A-1.570.027 précité.
• un écrou 10 monté sur la tige 6.
• une bande notamment métallique 11, formant sangle, dont chaque partie d'extrémité traverse avec un large jeu une lumière latérale 12 de l'embase 4 puis, au-dessous de celle-ci, est fixée à l'écrou 10 au moyen d'une vis 13. La sangle est guidée latéralement dans chaque lumière 12, laquelle présente, à l'opposé de l'autre lumière 12, une surface 14 d'appui de la sangle. Les surfaces 14 divergent en direction de l'objet 2 et peuvent être bombées. En variante, ces surfaces d'appui pourraient être définies par la surface périphérique de deux galets, comme décrit dans le FR-A précité.
• un patin d'appui sur le filtre 2, référencé 15, qui est articulé dans la chape 5 autour d'une goupille 16 dont l'axe porte la même référence. La goupille 16 dépasse de chaque côté du patin et tourillonne dans deux orifices prévus dans les ailes de la chape 5. Le patin est disposé librement entre les deux brins de la sangle 11.
• un ressort 17 en épingle à cheveux, enroulé sur la goupille 16. Une extrémité de ce ressort prend appui sur la face supérieure de l'embase 4, et son autre extrémité sous une deuxième goupille 18 solidaire du patin 15. Cette goupille 18 dépasse de chaque côté du patin, et ses extrémités sont reçues dans des lumières arquées de centre 16 prévues dans les ailes de la chape 5.

The strap wrench 1 comprises:

• a rigid body 3 which comprises a base 4 on which there is a yoke 5 whose wings are parallel to the plane of the drawing.
• a threaded rod 6, which may be multi-threaded, whose lower end carries a knurled actuating knob 7 while its upper end 8, smooth and of reduced diameter, journalled in a central bore 9 of the base 4 in being immobilized in translation in this piercing, in the manner described in FR-A-1570027 supra.
• a nut 10 mounted on the rod 6.
• a particularly metal band 11 forming a strap, each end portion passes through a wide clearance a lateral light 12 of the base 4 and, below this, is fixed to the nut 10 by means of a screw 13. The strap is guided laterally in each lumen 12, which has, opposite the other lumen 12, a support surface 14 of the strap. The surfaces 14 diverge towards the object 2 and can be curved. As a variant, these bearing surfaces could be defined by the peripheral surface of two rollers, as described in the aforementioned FR-A.
• a support pad on the filter 2, referenced 15, which is articulated in the yoke 5 around a pin 16 whose axis bears the same reference. The pin 16 protrudes on each side of the shoe and pivots in two holes provided in the wings of the yoke 5. The pad is freely disposed between the two strands of the strap 11.
• a spring 17 hairpin wound on the pin 16. One end of this spring bears on the upper face of the base 4, and its other end under a second pin 18 integral with the pad 15. This pin 18 protrudes from each side of the pad, and its ends are received in arcuate center lights 16 provided in the wings of the yoke 5.

The upper face 20 of the pad has a generally cylindrical shape with generatrices perpendicular to the mean plane of the strap 11, which is the plane of the drawing. The guide line of the cylinder may be circular, for example of radius corresponding to the smallest radius of the filters to be operated, as shown, or, alternatively, in V very flared. The face 20 is further shaped sawtooth inclined to the right of the figures, to tend to hang on the object 2 in a preferred direction as it will appear later.

The entire body 3 and the rod 6 with its button 7 is symmetrical with respect to a plane P parallel to the axis O, or perpendicular to the mean plane of the strap, which passes through the axis XX of the rod 6 The axis 16 is shifted to the right with respect to the plane P, and the axis of the pin 18 is shifted to the left with respect to this plane.

So, at rest ( figure 1 ), the spring urges the shoe 15 to tilt about the axis 16, in the clockwise direction, until the pin 18 abuts against the upper end of the lights 19.

We will now describe the unscrewing of the filter 2 by means of the key 1.

The strap is loosely arranged around the filter ( figure 1 ). Then, turn knob 7 clockwise ( figure 2 ). Due to the lateral guidance of the two strands of the strap in the lights 12, this movement causes the descent of the nut 10 along the threaded rod, and thus the shortening of the useful length of the strap, that is to say, its length which emerges from the body 3.

When the pad has applied to the filter, the strap begins to stretch by applying on the zones 14 of the base 4. The continued rotation of the button 7 forces the body 4-rod 6 to switch slightly clockwise (arrow F1 on the figure 2 ) around the axis 16, by compressing the spring 17. The pin 18 then leaves the upper end of the lights 19.

The operator feels a resistance to the rotation of the button 7 significantly increased from the beginning of this compression of the spring 17. It can then stop acting on the button 7, the key is in the position of the figure 2 and is ready to drive the filter 2. If it nevertheless continues to turn the knob 7, the tension of the strap will be limited by the arrival of the pin 18 in abutment against the lower end of the lights 19.

The strap 11 then comprises two strands stretched. One strand 11A, right on the figure 2 located between the point 21A where, on this side, the strap tangentially leaves the filter 2, and the distal point 22A of its region of contact with the right zone 14A ( Figure 5 ); and a left-hand strand 11B defined analogously. Area 14A is located on the same side as geometric axis 16 with respect to XX and distal end 22A is further from axis XX than is geometric axis 16.

The operator then pushes the 6-button rod assembly 7 counter-clockwise (arrow F2 of the Figure 3 ). The saw teeth of the bearing face 20 of the pad cling tightly to the filter, and this action drives in one piece the key and the filter in rotation about the axis O ( figure 3 ).

This is due to the fact that, thanks to the offset position of the axis 16 with respect to the axis XX, the axis 16 thus being closer to point 22A than point 22B, the distance 21B-22B tends to increase more than the distance 21A-22A tends to decrease so that the strap 11 is tighter.

During this phase of pushing to the right (arrow F2 of the Figure 3 ), the resistance to the unscrewing of the filter can cause a slight tilting of the handle relative to the pad around the axis 16, but this tilting is limited by the tension of the strap or the return of the pin 18 abutting the upper end of lights 19.

• pendant la phase de serrage de la sangle sur le filtre, θ augmente, et
• pendant la poussée dans le sens F2, θ tend à diminuer.

We thus see that, if θ represents the algebraic angle between on the one hand the ZZ axis parallel to the axis XX and passing through the axis 16, and on the other hand the line YY which connects the center O of the filter to the axis 16, the positive direction being that of the force in the direction F2, counterclockwise in the drawings), then:

• during the tightening phase of the strap on the filter, θ increases, and
• during the push in the direction F2, θ tends to decrease.

After a certain angle of anti-clockwise rotation of the filter, for example limited by neighboring engine parts, the operator pushes the 6-button rod assembly 7 in the opposite direction F1 ( Figure 4 ).

The distance 21B-22B tends to decrease more than the distance 21A-22A tends to increase, so that the strap 11 is less tight. Taking into account, moreover, the orientation of the sawtooth of the shoe, there is an overall sliding of the tool around the filter 2, clockwise.

The key 1 thus has a "ratchet" effect, which makes it possible to perform a reciprocating movement of the handle several times in order to unscrew the filter 2 by several successive angles.

In the example described, the two stops for the pin 18 limit the angle θ to the range [0.25 °]. For each filter diameter, there is a range of tightening values, and therefore a range of values of θ after tightening ( Figure 2 ), for which the ratchet effect is obtained. In the example under consideration, the amplitude of this range is approximately 10 to 15 °. It depends on the geometry and the coefficient of friction between the pad and the filter.

It is important to note that, as the spring 17 constantly slams the pad against the filter, the angulation that appears between the pad and the handle during the return movement or "ratcheting" is instantly overtaken as soon as the action in the F1 direction stops. The tool is particularly ergonomic because it does not require substantial wrist twisting, after the return movement, to begin the next drive of the filter.

In the embodiment of the figure 5 , the handle is embodied by a tubular shaft body 23, for example of plastic material in particular loaded with reinforcing fibers, fitted on the base 4 on one side and the button 7 on the other. The outer surface of the latter is in line with that of the body 23.

In addition, the bearing surfaces 14 are asymmetrical with respect to the axis XX, the drive-side surface 14A being further away from the button 7 than the opposite surface 14B. As before, the axis 16 is offset relative to the axis XX of the handle and is closer to point 22A than point 22B regardless of the diameter of the filter 2 in the range of diameters provided. In other words, the axis 16 is shifted (to the right on the Figure 5 ) relative to the X'-X 'mediator of the segment 22A-22B, as before. The zone 14A is located on the same side as the geometric axis 16 with respect to the line X'-X 'and the distal end 22A is further from this line X'-X' than is the geometric axis 16.

To be able to change the strap, the body 23 comprises, near the base 4, two opposite orifices 24 which allow a screwdriver to access the screws 13 when the nut 10 is in its upper position.

In this embodiment, the pad 15 is made by a stack of sheets riveted together at 25. In a variant, the two outer plates may be the two wings of a U-folded sheet, with between them one or more additional sheets forming spacers.

As a variant, the surface 14A may be closer to the button 7 than the surface 14B, provided that the axis 16 remains closer to the point 22A than to the point 22B. This has been schematized on the Figure 5 by an X "-X" mediator of the segment 22A-22B, which passes between the axis XX of the handle and the axis 16.

In another particularly simple embodiment ( Figure 6 ), the key according to the invention has neither mechanism for adjusting the strap or spring. The elements corresponding to the embodiment of the Figures 1 to 4 , whose geometry is conserved, bear the same references, increased by 100.

• d'un corps rigide 103 formant manche 123, embase 104 avec ses surfaces d'appui 114 et chape 105. Ce corps peut être moulé d'une seule pièce ou constitué de deux pièces moulées assemblées, par exemple par deux vis, suivant un plan de joint vertical;
• d'une goupille 116 portée par la chape 105 et sur laquelle est articulé librement le patin 115; et
• d'une sangle 111 dont une partie d'extrémité au moins comporte plusieurs orifices alignés 27.

The key consists of:

• a rigid body 103 forming a handle 123, base 104 with its bearing surfaces 114 and clevis 105. This body may be molded in one piece or made of two molded parts assembled, for example by two screws, in a plane vertical joint;
• a pin 116 carried by the yoke 105 and on which is freely articulated the pad 115; and
• a strap 111 of which at least one end portion has a plurality of aligned orifices 27.

The base 104 carries on each surface 114 a lug 28 projecting, which can receive an orifice 27. Each pair of orifices corresponds to a predetermined filter diameter. In addition, a pin 118 carried by the shoe, passing through two arcuate apertures 119 of the yoke 105, limits the angular deflection of the shoe, in both directions, around the pin 116.

Such an embodiment is particularly suitable for repetitive work performed on filters of all the same diameter.

Of course, alternatively, the tool may be provided with a set of straps each having a single orifice 27 at each end, each strap corresponding to a predetermined diameter of filters.

In another variant, at least one of the pins 28 could be provided at the top of the sleeve 123, as indicated in dashed line on the Figure 6 .

It is understood that it is possible to add a spring 17 in this embodiment.

In another embodiment not shown, the tilting axis of the pad may be purely geometric without being materialized by a pin such as 16. It suffices for the bottom surface of the pad to have a convex cylindrical shape with an arcuate section. circle and cooperates with a concave concave guide surface provided on the body 3.

The Figures 7 and 8 show the external appearance of the strap key of the figure 5 , associated with minimum and maximum diameter filters.

Note that in its current part, the body 23 has a roughly elliptical section, with its major axis in the general plane of the strap. This section is progressively transformed into a circular section in the distal end portion of the body 23, adjacent to the button 7.

The button 7 comprises gouweres 29 to facilitate its grip, and the body 23 has a few recesses 30 and carries an arrow 31 which indicates the direction of drive. The gouweres 29 allow the operator to distinguish the button 7 from the body 23 without visibility, an effect that can be reinforced by the use of a material having a distinctly different feel.

It is understood that in each of its embodiments, the strap wrench according to the invention can be used for screwing as for unscrewing, by simply reversing face to face.

The Figures 9 and 10 show the appearance of a slightly modified version of the tool, in which the shoe 15 has saw teeth only in its two circumferential end regions. In addition, this pad is made by U-folding a sheet and adding spacers 32, as described above.

The Figure 11 represents a variant in which the handle body 23 consists of two half-shells 23A, 23B, for example of light alloy or plastic especially filled with reinforcing fibers. The front parts thereof together form the base 4 and the yoke 5, the base being defined by respective overlapped perforations 4A, 4B integral with the half-shells. The smooth front portion 8 of the rod 6 passes through the orifices of these two projections, and is held axially by an elastic ring 33 located between the projections 4A and 4B and which engages in a groove 34 of the portion 8. The nut 10 is guided in translation by longitudinal inner reliefs of the half-shells. The lower ends of the two half-shells are held together by interlocking thereon with an end skirt 7A of the button 7.

Disassembly can be done by simply pulling down the button 7, or in the following manner.

The button 7 is fully unscrewed, which causes the nut 10 to rise up against the projection 4A. Continuing unscrewing, the rod 6 is pushed down, which moves the rod 33 and releases the rod. The button-rod assembly can then be lowered, and the two half-shells apart.

Similarly, the assembly can be carried out either by directly pushing the nose of the rod through the projections 4A and 4B, or by closing first the half-shells around the rod 6 and the nut 10, then screwing the button 7. The nut 10 goes down, then against an inner flange 23C, 23D of the half-shells, then the pursuit of the face raises the 6-button rod assembly 7, so that the nose of the rod passes through the projections 4A and 4B. At the end of the race, the ring snaps into the groove of the rod and the skirt 7A of the button fits into position.

In the variant of Figures 12 and 13 the saw teeth of the shoe 15 are distributed in two regions 20A, 2OB of the bearing face 20, with an intermediate clearance. The surfaces 25A, 25B tangent to the teeth of each of these regions may be planar as shown, but also convex cylindrical, or cylindrical concave with a radius greater than the largest radius of the filters 2. The combination of the surfaces 25A and 25B is such that for the most common filters in the range, a tooth and a single 26A, 26B, of each region is in contact with the filter.

As can be seen from the Figure 13 each tooth 26A, 26B has a generally trapezoidal shape, with on the left a surface 27A, 27B which forms with the surface 25A, 25B a relatively large angle α , followed by a surface 28A, 28B which forms with the surface 25A, 25B a relatively small angle β . The right edge 29A, 29B of the tooth is nearly perpendicular to the surface 25A, 25B, and it is connected by a rounded 30A, 30B to the surface 28A, 28B of the next tooth.

The teeth 26A, 26B are cut in two times: a first time to give the general shape of the teeth, and a second time to cut the portion 28A, 28B of the tooth. The second cut is provided to leave a tooth edge whose width is equal to the tolerance of the accuracy of the second cut with respect to the first.

It is understood that, in each embodiment, the strap wrench according to the invention provides a unidirectional drive of the key through a toggle effect. The pivot point of this toggle is the 16 or 116 axis, one side is the segment 0-16 or 0-116, and the other side is a segment which extends from the axis 16, 116 to a point integral with the handle of the key, which, in the examples described, is close to the axis handle and surfaces 14, 14A-14B or 114.

Claims (20)

1. Strap wrench (1) for unidirectionally driving an object (2) of generally cylindrical shape, of the type comprising:

   - a part forming a handle (6, 7; 6, 7, 23; 123),

   - a strap (11; 111), in particular made of metal, in the form of a loop, of which the two opposing portions (11A, 11B) cooperate with two zones (14; 114) integral with the handle when the strap tightly encloses said object,

   - the handle being provided, between said two zones, with a pad (15; 115) for bearing against said object, said bearing pad not being connected to the strap and having a bearing face (20) of generally cylindrical shape with generatrices perpendicular to the general plane of the strap,

   characterised in that the pad (15; 115) is tiltably mounted relative to the handle about a geometric axis (16; 116) associated with the handle and perpendicular to the general plane of the strap, said axis being arranged so that if the pad and the strap are both clamped tightly against said object, an action on the handle (6, 7; 6, 7, 23; 123) exerted in a first direction (F2) causes the driving of the object (2) and exerted in the other direction (F1) causes the sliding of the pad and of the strap on the object; and in that the handle (6, 7; 6, 7, 23; 123) and the pad (15; 115) comprise first stop means which limit the angular displacement of the handle (6, 7; 6, 7, 23; 123) relative to the pad (15; 115) in said first direction when the action is exerted on the handle in the first direction (F2).
2. Wrench according to Claim 1, characterised in that said clamping is between a minimum value and a maximum value.
3. Strap wrench according to Claim 1 or 2, characterised in that said geometric axis (16; 116) is offset laterally relative to the general axis (X-X) of the handle (6, 7; 6, 7, 23; 123) .
4. Wrench according to Claim 3, characterised in that said geometric axis (16; 116) is closer to the general axis (X-X) of the handle (6, 7; 6, 7, 23; 123) than the distal end (22A) of said zone (14; 114) which is located on the same side as said geometric axis (16).
5. Strap wrench according to any one of Claims 1 to 4, characterised in that said geometric axis (16; 116) is offset laterally relative to the perpendicular bisector (X'-X') of the segment defined by the distal ends (22A, 22B) of said two zones (14; 114) integral with the handle (6, 7; 6, 7, 23; 123).
6. Strap wrench according to Claim 5, characterised in that said geometric axis (16; 116) is closer to said perpendicular bisector (X'-X') than the distal end of said zone (14; 114) which is located on the same side as said geometric axis (16).
7. Strap wrench according to any one of Claims 1 to 6, characterised in that the pad (15) is elastically urged so as to be able to tilt relative to the handle about said geometric axis (16).
8. Strap wrench according to Claim 7, characterised in that the pad (15) is elastically urged in the direction opposing said first direction (F2).
9. Strap wrench according to any one of Claims 1 to 6, characterised in that the pad (115) is mounted so as to be able to tilt freely and with limited amplitude about said geometric axis (116).
10. Strap wrench according to any one of Claims 1 to 9, characterised in that the handle (6, 7; 6, 7, 23; 123) and the pad (15; 115) comprise second stop means which limit the tilting of the pad relative to the handle in said first direction (F2).
11. Strap wrench according to any one of Claims 1 to 10, characterised in that the pad (15; 115) is articulated on a member (5; 105) integral with the handle about a pivot pin (16; 116) of which the axis forms said geometric axis.
12. Strap wrench according to any one of Claims 1 to 10, characterised in that the pad comprises, on the same side as the handle, a guide surface of circular section which cooperates with a conjugate surface of circular section, which is integral with the handle, of which the axis forms said geometric axis.
13. Strap wrench according to any one of Claims 1 to 12, characterised in that the bearing face (20) of the pad (15) has a coefficient of friction which is markedly greater in one rotational direction of the wrench than in the other direction, for example by means of inclined saw teeth provided on said bearing face.
14. Strap wrench according to Claim 13, characterised in that said bearing face (20) has two bearing zones (20A, 20B) which define, for each object diameter (2) belonging to a series of predetermined diameters, two substantially pointed regions for bearing against the surface of the object.
15. Strap wrench according to Claim 14, characterised in that said zones (20A, 20B) comprise teeth of generally trapezoidal shape with points inclined in said first direction (F2).
16. Strap wrench according to any one of Claims 1 to 15, characterised in that it comprises a device (6, 10) for adjusting the useful length of the strap (11), said device being in particular a screw-nut mechanism and comprising an element (10) which is displaceable along the handle (6, 7) and to which at least one end and preferably the two ends of the strap is and/or are fixed.
17. Strap wrench according to Claims 10 to 16 taken together, characterised in that said second stop means limit the angular displacement of the handle (6, 7; 6, 7, 23) relative to the pad (15) when the adjusting device (6, 10) is actuated in the direction which reduces the useful length of the strap (11).
18. Strap wrench according to any one of Claims 1 to 17, characterised in that it comprises a single strap of which at least one end region comprises a plurality of spaced-apart anchoring points (27) designed to be removably fixed to a corresponding anchoring point (28) integral with the handle, or vice versa.
19. Strap wrench according to any one of Claims 1 to 17, characterised in that it comprises a set of straps of different lengths of which each comprises, at each end, an anchoring point (27) designed to be removably fixed to a corresponding anchoring point (28) integral with the handle.
20. Strap wrench according to any one of Claims 1 to 19, characterised in that the unidirectional driving results from a toggle action, the point of articulation of the toggle being said geometric axis (16; 116).

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