EP1375072B1 - Torque tool, especially wrench, with snap means for adjusting the torque - Google Patents

Abstract

An axial spring (61) pushes the support onto the driving element and its compression determines the tool release torque. A torque adjusting handle (7) rotates on the body to activate the spring compression nut (47). It comprises a first toothed crown wheel (41) fixed to the body and a second complementary toothed crown wheel (43) fixed to rotate with the handle. The second crown wheel can slide axially between an engaged position meshing with the first crown wheel and a disengaged position. The second crown wheel is returned to the engaged position by an axial return spring (45). The dynamometer spanner comprises a driving element, a hollow outer body (3) and an axial support (65,67) onto the driving element.

Description

The present invention relates to a tool, in particular a torque wrench, comprising a driving element, an elongated outer hollow body in which the driving element is mounted with the possibility of pivoting, an axial bearing means on the drive member, an axial spring urging said biasing means toward the drive member and whose compression determines a triggering torque of the tool, and a rotation torque adjusting handle rotatably mounted on the body for actuate a compression means of the spring.

Dynamometric tools of this type can be keys, but also screwdrivers.

Numerous tools of the above-mentioned type are known in the state of the art, in which the setting of the triggering torque is effected continuously by rotation of a threaded element, this threaded element being devoid of a stop position.

Such tools are not adapted to a high accuracy of the setting of the triggering torque, the angular position of the adjusting handle being liable to vary during the operation of the tool. In addition, the accuracy of the adjustment is reduced because the operator has only a visual sensation of the setting.

A first object of the invention is to overcome these disadvantages, and to propose a dynamometric tool in which the setting of the triggering torque can be achieved with great precision, with good sensations of use for the operator, not only visual but also tactile and auditory.

For this purpose, according to a first embodiment, the tool is according to claim 1, or according to a second embodiment, is in accordance with claim 11.

Preferably, the tool according to the first embodiment of the invention is according to one of claims 2 to 4.

Also known in the state of the art (GB-A-2 306 363, disclosing the features of the preambles of claims 1 and 11) torque wrenches, in which the handle is not only rotatably mounted on the outer hollow body, but further screwed into the hollow body, so that it can be actuated in a helical motion. In such keys, the movement of the handle relative to the hollow body can be blocked by a locking device which comprises two sleeves with complementary axial peripheral teeth. A first sleeve is slidably and non-rotatably mounted on the body of the key, so as to follow the axial movement of the handle relative to the body. The second sleeve is mounted on the handle so as to follow the general movement of the handle relative to the body of the key, the second sleeve being further movable in axial translation relative to the handle over a length slightly greater than the height of the teeth, so as to selectively engage the teeth of the sleeves mutually or disengage them from one another. The axial displacement of the second sleeve relative to the adjustment handle is obtained by the translational actuation of an outer locking ring with respect to the handle.

The mutual engagement of the teeth has the effect of securing the handle with the body of the key, thus locking the setting of the trigger torque, while in the released position of the teeth, the setting of the trigger torque can be modified by the user.

Such a locking device has the major disadvantage of the complexity due to the implementation of at least three parts, namely the two sleeves and the locking ring, all movable relative to the key body, which increases the complexity of design, parts manufacturing and assembly.

Such a locking device therefore significantly increases the manufacturing costs of torque wrenches that are provided.

Another object of the invention is to remedy these drawbacks, and to provide a dynamometric tool equipped with a locking device for adjusting the triggering torque, the complexity and cost of manufacture of which are drastically reduced for a identical and even improved efficiency and accuracy.

For this purpose, a dynamometric tool according to the first pre-formed embodiment of the invention is in accordance with claim 5.

Preferably, the tool according to the first embodiment is according to one of claims 6 to 10.

Preferably, the tool according to the second embodiment is according to one of claims 12 to 18.

• la Figure 1 est une vue en perspective d'une clé dynamométrique conforme à une première forme de réalisation de l'invention, le levier de verrouillage étant en position déverrouillée;
• la Figure 2 est une vue en coupe suivant la ligne 2-2 représentée à la Figure 1 ;
• la Figure 3 est une vue de détail en coupe dans le même plan, à plus grande échelle, de la partie arrière de la clé des Figures précédentes ;
• la Figure 4 est une vue de détail analogue, encore à plus grande échelle, représentant les couronnes dentées ;
• la Figure 5 est une vue de détail en perspective à plus grande échelle, du curseur de la clé des Figures précédentes ;
• les Figures 6 et 7 sont des vues analogues respectivement aux Figures 1 et 3, le levier de verrouillage étant en position verrouillée ;
• la Figure 8 est une vue en coupe dans un plan axial d'une clé dynamométrique conforme à une deuxième forme de réalisation de l'invention, l'organe de verrouillage étant en position verrouillée ;
• la Figure 9 est une vue de détail en coupe dans le même plan, à plus grande échelle, du tronçon présentant l'organe de verrouillage, ce dernier étant en position verrouillée ;
• la Figure 10 est une vue en coupe suivant la ligne 10-10 représentée sur la Figure 9 ;
• la Figure 11 est une vue en perspective du doigt à secteur denté des Figures 8 à 10 ; et
• les Figures 12 et 13 sont des vues analogues à la Figure 9, l'organe de verrouillage étant en position déverrouillée, et le secteur denté étant dans des positions respectivement engagée et dégagée par rapport à la couronne dentée.

Particular embodiments of the invention will now be described in more detail with reference to the accompanying drawings, in which:

• Figure 1 is a perspective view of a torque wrench according to a first embodiment of the invention, the locking lever being in the unlocked position;
• Figure 2 is a sectional view taken along the line 2-2 shown in Figure 1;
• Figure 3 is a detail view in section in the same plane, on a larger scale, of the rear part of the key of the preceding figures;
• Figure 4 is a similar detail view, still on a larger scale, showing the ring gear;
• Figure 5 is a detail view in perspective on a larger scale, the cursor of the key of the preceding figures;
• Figures 6 and 7 are views similar respectively to Figures 1 and 3, the locking lever being in the locked position;
• Figure 8 is a sectional view in an axial plane of a torque wrench according to a second embodiment of the invention, the locking member being in the locked position;
• Figure 9 is a detail view in section in the same plane, on a larger scale, of the section having the locking member, the latter being in the locked position;
• Figure 10 is a sectional view taken along the line 10-10 shown in Figure 9;
• Figure 11 is a perspective view of the toothed sector finger of Figures 8 to 10; and
• Figures 12 and 13 are views similar to Figure 9, the locking member being in the unlocked position, and the toothed sector being in positions respectively engaged and disengaged relative to the ring gear.

In Figure 1, there is shown a torque wrench according to a first embodiment of the invention, the key having a longitudinal axis XX, oriented "back" in "before". Key 1 which has been shown essentially comprises a tube 3 of generally cylindrical shape, defining an external hollow body, a head or driving element 5 towards the front of the key, a handle 7 for gripping the tool and of Trigger torque adjustment, located towards the back of the key. The key 1 further comprises, in an intermediate region, a fixed ring 9, integral with the tube 3, and a fixed guard 11, secured to the ring 9 and fitted on a front section of the handle 7.

The key 1 is further provided with a graduations holder 13, in the form of a plated lamella and fixed on the tube 3, and a slider 15 (FIGS. 2 and 3) able to move axially on the graduated blade. 13 to indicate the value of the trip torque.

The tube 3 and the head 5 are preferably metal parts.

As shown in FIG. 2, the driving head 5 is a part which comprises a front block 21 projecting from the front of the tube 3, an intermediate hinge zone 23, and a rear tail 25 fitted into the tube 3 with play and mounted with possibility of pivoting on the tube 3 about a ZZ axis materialized by a pin 27.

In this Figure, the X-Z plane of section is assumed to be vertical and the X-X axis is assumed to be horizontal, for the convenience of the description.

The block 21 has, from its front end, an actuating device 29. The latter is typically a reversible reversible ratchet head, provided with a drive square on which fits a screw socket.

The pin 27 traverses diametrically the hinge zone 23 and the tube 3, being integral with the latter.

The orientation of the key shown in Figure 2 corresponds to the actuation of a screw or a nut (not shown) whose axis is vertical.

On the rear part of the tube 3 is mounted coaxially handle 7, rotating about the horizontal axis XX. The handle is hollow internally so as to slide on the tube 3. It is attached to a inner threaded rod 31 coaxial, the latter being secured to the handle 7 by a pin 33 passing through a rear end orifice of the threaded rod 31. The threaded rod 31 has a threaded front portion 31A, an intermediate portion 31B forming a bearing, and a rear drive portion 31C of polygonal cross section (hexagonal or square for example) in which is made the orifice.

Reference is now made to Figure 3.

The intermediate portion 31B, of circular cross-section, is pivotally supported in a coaxial sleeve 35 rigidly fixed to the rear end of the tube 3, the intermediate portion (or section) 31B further having an annular shoulder 37 for stopping in translation. axial axis of the threaded rod, bearing on the sleeve 35.

On the rear section 31C is fitted a movable sleeve 39 of complementary inner shape, this movable sleeve 39 thus being made integral in rotation with the threaded rod 31 and slidable thereon within the axial internal recess of the handle 7.

The fixed sleeve 35 and the movable sleeve 39 are provided with complementary toothed crowns 41, 43, the teeth of the rings 41, 43 being complementary, and turned facing one another. The teeth of the rings 41, 43 extend peripherally and are oriented axially (Figure 4).

A washer 44 mounted free in axial translation on the drive section 31C is interposed between the movable ring 43 and a rear transverse wall 46 of the internal recess of the handle 7. An axial spring 45 of low stiffness, mounted coaxially on the section 31C, is supported by a first end on the movable ring 43, and by its second end on the washer 44, so as to axially bias the movable ring 43 in a position, in which the ring gear 41 and 43 engage one another.

The teeth of the toothed crowns 41, 43 are designed so that the clearance of the crowns, from an engaged position, is effected by a low actuation force, almost insensitive, the operator. For this, the teeth of the rings 41, 43 are designed so that the axial reaction, in a contact region between two complementary teeth, is greater than the tangential reaction opposing rotation, or of the same order.

It is understood that it is thus possible to achieve a so-called "ratcheting" adjustment of the angular position of the handle 7 on the tube 3: when the handle 7 is rotated on the tube 3, the threaded rod 31 and the movable sleeve 39 are integrally rotated, so that the ring gear 43, alternately undergoes axial recoil movements, the return force of the spring 45 is then overcome, and in advance, under the effect of the thrust force of the spring 45. The cooperation of the teeth of the rings 41, 43 in different angular positions of the movable ring 43 relative to the fixed ring 41, defines rotational stops of the handle 7 relative to the tube 3.

On the threaded section 31A of the rod 31 is mounted a complementary nut 47, locked in rotation relative to the tube 3, so that a rotation of the threaded rod 31 causes an axial displacement, without rotation, of the ecro 47 by relative to the tube 3, inside the latter.

Towards the rear of the tube 3 is provided an oblong slot 49 extending axially.

The slider 15, which has been shown alone in FIG. 4, is fixed rigidly to the nut 47 projecting through the oblong slot 49.

As can be seen in FIG. 5, the slider 15 essentially consists of a ring 51 in the form of an arc and an axial arm 52 whose free end edge 53 opposite the ring 51 indicates, by superposing with the graduations of the graduated blade 13, the triggering torque set by rotation of the handle 7. The ring 51 fits over the periphery of the nut 47. A stud 55 projecting radially from the inner face of the ring 51 is inserted into the nut 47. The opposite lateral faces 59 of the stud 55 cooperate with the lateral edges of the oblong slot 49, so that the rotation of the slider 15, and consequently that of the nut 47, is blocked during the rotation of the threaded rod 31.

Referring again to Figure 3, it should be noted that the shoulder 37 defines a rear axial stop for the nut 47.

The front face of the nut 47 bears on the rear end of a compression spring 61 having a high stiffness, this spring being fitted coaxially on the threaded section 31A of the rod 31, inside the tube 3.

The spring 61 is secured, at its front end, to a ball plate 63, the ball itself being supported on the rear face of a pusher 65.

The pusher 65 is generally cylindrical in shape and can slide axially while being guided in the tube 3, under the effect of the biasing of the spring 61.

The rear face of the tail 25 and the front face of the pusher 65 are vertical faces facing each other, each of which has a recess. A cubic die 67 applies, at rest, on the bottoms of these recesses.

The assembly formed of the pusher 65 and die 67 defines an axial bearing means on the drive head 25.

It is understood that the axial position of the nut 47 determines the compression of the spring 61, and thus the axial bearing force of the pusher 65 on the tail 25, through the die 67. When the maximum torque determined by the compression of the spring 61 is reached, the die 67 tilts and backs the pusher. The tail 25, by pivoting around the pin 27, then comes into contact with the inner surface of the tube 3.

A lever 71 is pivotally mounted on the rear end of the driving section 31C of the threaded rod 31, about a transverse axis represented by the pin 33. The lever 71 has an actuating portion 73 which, in the position of the lever shown in Figures 1 to 3, protrudes axially from the rear of the handle 7. It further comprises a block 75 forming a cam, facing the washer 44 and bearing on it by its cam surface .

The lever 71 forms, with the sleeves 35, 39 and the washer 44, a releasable device for locking the setting of the trigger torque, as will be explained now.

In the position of the lever 71 shown in Figures 1 to 3, that is to say in the unlocked position, the washer 44 is axially separated from the movable sleeve 39 by a distance D greater than the height of the teeth of the rings 41, 43, so that the movable sleeve 39 can undergo axial position variations on the drive section 31C, under the effect of the rotation of the handle 7. Thus the handle can be freely rotated by the user, so as to adjust the compression of the spring 61 and the value of the triggering torque.

When the user wants to lock the trigger torque setting to use the tool without fear of disturbance, he operates the lever 71 by pressing the operating portion 73 downwards, so as to make a quarter turn to the lever 71.

The lever is at the end of this movement in the position shown in Figures 6 and 7.

Under the effect of the rotation of the cam 75, the washer 44 is moved axially towards the sleeve 39, until it bears against the rear surface of the latter. Optionally, the cam 75 is provided so that the washer 44, in the locked position of the lever 71, is separated from the movable sleeve 39 by a distance d less than the height of the teeth of the rings 41, 43 (the "height"s'). is understood as the active height of the teeth, that is to say the height in engagement of the teeth).

It will be understood that, in this locked position of the lever 71, the return spring 45 is strongly compressed and produces its maximum stressing force of the ring gear 41, 43 in their engaged position. The mobile ring 43 is limited, in its axial movement towards the rear on the drive section 31C, by the washer 44 and the block 75. In this position, the movable ring 43 can not get out of its position. engagement with the fixed ring 41, and accordingly the handle 7 can no longer be rotated to change the trigger torque.

As seen in Figures 6 and 7, the operating portion 73 of the lever 71 is substantially complementary to the rear end shapes of the handle 7, so that in the locked position, the lever 71 is almost retracted in the 7. This arrangement allows an operator to use the tool without feeling any discomfort in gripping the handle when the lever is locked. Conversely, when the lever 71 is unlocked, it projects at the rear of the handle 7, as has been seen in 1 to 3, which indicates to the operator, in a visual and tactile manner, that the setting of the triggering torque is not locked.

As can be seen in particular in FIG. 6, the shape of the operating portion 73 of the lever 71 is provided so as to define, when the lever is locked, a notch 77 with the handle 7, this notch allowing the operator to easily grasp the lever to unlock it.

In Figure 8, there is shown a torque wrench according to a second embodiment of the invention.

In a similar manner to the first embodiment, the key 101 shown in FIG. 8 comprises a body 103, a handle 107 for gripping and adjusting the triggering torque, and a unitary assembly consisting of a ring 109 and a sheath 110, this ring-sheath assembly being movable relative to the body 103. The handle 107 is integral internally with the sheath 110, through which it is fitted on the body 103 at the rear end thereof.

In this Figure is also shown a pin 127 embodying the pivot axis Z-Z of a drive head (not shown) on the body 103.

As for the description of the first embodiment, it will be assumed, for the description of the second embodiment, that the longitudinal axis X-X of the key 101 is horizontal, while the axis Z-Z is vertical.

In a similar manner to the first embodiment, the key 101 comprises a threaded rod 131 disposed coaxially inside the body 103 and integral with the handle 107, which is mounted, integrally with the sleeve 110, so as to be able to turn on the body 103. Inside the body 103 is also arranged coaxially a nut 132, the nut being integral with the body 103. Under the effect of a rotation of the handle 107, the threaded rod 131 cooperates with the nut 132 and moves axially relative to the body 103.

The axial displacement of the threaded rod 131 acts on the compression of an axial spring (not shown), and thus on the triggering torque of the key, thanks to mechanical elements similar to those of the first embodiment, and which will not be detailed again.

Referring now to FIGS. 9 to 11, there will be described in more detail the elements for defining a ratchet setting of the angular position of the handle on the body, and thus the trigger torque of the key.

It is observed that the key comprises a toothed coaxial ring 141 axially movable on the body 103. The ring gear 141 has a radial peripheral toothing with inclined flanks, the teeth being turned outwards and evenly distributed over the entire periphery. The ring gear 141 is at least integral in rotation on the body 103 by virtue of a radially inward projecting radial plate 141A, and engaged in a corresponding axial groove 103A formed in the body 103 at the outer periphery. The ring gear 141 is locked axially relative to the ring-sheath assembly, on one side by the ring 109, and on the other by the sheath 110, with the games close.

The key 101 further comprises a finger 142 provided with a toothed sector 143, and a coaxial locking ring 171, external to the ring gear 141.

The toothed sector 143 has an inwardly directed radial toothing, complementary to that of the ring gear 141. The toothed sector 143 extends over an angular sector of small value, in particular substantially less than 180 °, and preferably, As in the example represented, less than 45 °. The teeth of sector 143 comprises, in the example shown, several teeth, here five in number, but could include only one.

The finger 142 is furthermore formed with a tab 174 projecting axially from the toothed sector 143, the free end of the tab 174 being provided with an internal radial return 175. The tab 174 acts as an axial stop relative to the ring 109, avoiding the involuntary axial displacement of the finger. The radial return 175 acts as a radial support allowing the good radial positioning of the finger 142.

The finger 142 is locked axially in position relative to the ring-sleeve assembly, between two radial stop surfaces of the ring 109 on the one hand, and the sleeve 110 on the other hand, with the games close.

The toothed sector 143 is formed externally with a circumferentially extending groove 177.

The sector 143 is engaged in a corresponding window of said sleeve 110 so that, when it is in mutual engagement with the ring gear 141, the outer surface of the toothed sector 143 extends continuously with that of the sleeve 110. The sleeve 110 is provided at its distal end with an outer wall 110A of cylindrical section, on which a peripheral groove 178 extends on the same axial section as the groove 177. Thus, the grooves 177, 178 together form a continuous groove on any the periphery of the sheath 110. In this peripheral groove 177, 178 is engaged an elastic biasing means 179, which can be either a split metal ring, as shown in the figures, or an elastic ring ring, made of elastomeric material, which forms a radial elastic return means of the toothed sector 143 in the engaged position with the ring gear 141.

The locking ring 171 is internally formed with a first cylindrical wall section 181 of smaller diameter, and a second cylindrical wall portion 182 of larger diameter.

The first wall section 181 is provided to coincide with the outer wall 110A of the sleeve 110 on which it is fitted, while the second wall section 182 is provided to provide sufficient clearance to the toothed sector 143, in the radial direction, for that the latter can be released from the ring gear 141. In other words, the difference in diameter of the two sections 181, 182 is greater than the mutual engagement height of the two teeth of the ring 141 and the sector 143.

The locking ring 171 is mounted on the sleeve 110, externally with respect thereto, so as to be able to slide axially with respect to the sheath 110, and consequently with respect to the body 103.

An elastic return member or axial spring 190 is disposed between the sleeve 110 and the locking ring 171, so as to axially engage the latter in the locking position of the finger 142 in mutual engagement with the ring gear 141.

The locking ring 171 is capable of sliding axially between this locking position and a position for disengaging or unlocking the finger 142 shown in FIGS. 12 and 13.

In the finger lock position, the first inner wall section 181 of the locking ring 171 makes close contact with the outer surface 110A of the sleeve 110, and with the outer surface of the toothed sector 143, preventing radial displacement. of the latter, so that the toothed sector 143 is maintained in engagement with the ring gear 141. Thus, by means of the ring gear 141 and of the toothed sector 143, the handle 107 is rotatably connected to the body 103, and the setting of the triggering torque is locked.

From the finger locking position, when the locking ring 171 is pulled backwards, against the biasing force of the axial spring 190, the clearance position of the finger 142 is reached. as shown in Figure 12.

In this position, the second larger diameter section 182 provides the toothed sector 143 with a radially outward clearance space. The biasing means 179, however, maintains the toothed sector 143 in engagement with the ring gear 141.

From this position shown in Figure 12, it is possible for a user to turn the handle 107. Under the effect of the rotation of the handle, the finger 142, by rotating integrally with the handle, can move radially, so that the toothed sector 143, during rotation, is disengaged from the ring gear 141, and alternately engages with the ring gear under the effect of the radial return force exerted by the elastic biasing means 179.

In FIG. 13, the finger 142 is shown in an unstable position, in which the toothed sector 143 is disengaged from the ring 141.

It is understood that the sectional plane in which Figures 9, 12 and 13 have been made is connected to the handle (and consequently to the finger 142) and not to the body 103.

It will be understood that the toothings of the toothed sector 143 and of the ring gear 141 together define setting deadening notches for the triggering torque, and that when the locking ring 171 is in the position of disengagement of the finger 142, the rotation of the handle 107 produces a so-called "rattling" effect generated by the passage notches during rotation due to the biasing effect of the biasing means 179.

It is understood that the invention applies particularly well to a torque wrench, as described above, but it is also suitable for other torque tools, for example screwdrivers.

The invention which has just been described makes it possible in particular to provide, for a dynamometric tool, a locking function of the setting of the triggering torque, by means of a device whose component parts have simple relative movements, as well as low manufacturing and assembly costs.

The invention realizes the locking function of the setting of the triggering torque from a gearwheel assembly which provides a ratchet setting. This type of ratchet setting provides the advantage of a large number of angular stopping positions, thus a high accuracy of the adjustment, as well as good sensations of use for the operator, the passage of the notches being audible and felt by the user.

The invention thus makes it possible to combine the advantage of a great sensitivity of the adjustment and that of a great simplicity of realization of the locking function.

Claims (18)

1. Dynamometric tool, especially a torque wrench, comprising a drive element (5), an outer hollow body (3) of elongate shape in which the drive element (5) is mounted so as to be capable of pivoting, a means (65, 67) for axially bearing against the drive element, an axial spring (61) which biases said bearing means (65, 67) towards the drive element (5) and the compression of which determines a disengagement torque of the tool, and a handle (7) for regulation of the disengagement torque rotatably mounted on the body (3) for actuating a means (47) for compressing the spring (61), characterised in that it comprises a first annular gearwheel (41) having peripheral teeth with inclined flanks, which is fixed with respect to the body (3), and a second annular gearwheel (43) having peripheral teeth, which is fixed with respect to the handle (7) for conjoint rotation and which is complementary to the first gearwheel, said second annular gearwheel (43) being capable of sliding axially between a clicking position engaged with the first annular gearwheel (41) and a position disengaged from said first annular gearwheel (41), the second annular gearwheel (43) being returned to the engaged position by a resilient axial return means (45) of a stiffness that is less than that of the spring (61), so that the various relative angular positions of the first (41) and second (43) annular gearwheels define stop notches of disengagement torque regulation.
2. Dynamometric tool according to claim 1, characterised in that the teeth of the first (41) and second (43) annular gearwheels are so arranged that, when they are in engagement, rotation of the second annular gearwheel (43) with respect to the first (41) produces, in a region of contact of two complementary teeth, an axial reaction on the second annular gearwheel (43) tending to disengage it from the first (41), the intensity of the axial reaction being of the same order as, or greater than, that of the tangential reaction opposing the rotation.
3. Dynamometric tool according to claim 1 or 2, characterised in that it comprises a threaded regulating rod (31) coaxially arranged at least in part in the handle (7) and connected to the handle (7) for conjoint rotation, and a nut (47), the rotation of which with respect to the body (3) is blocked and which is capable of axial translation within the body (3), said nut (47) being in engagement with the threaded rod (31) so that rotation of the handle (7) moves the nut (47) in axial translation with respect to the body (3), said nut (47) bearing against one end of the thrust spring (61) so as to compress it as a function of its axial position.
4. Dynamometric tool according to claim 3, characterised in that it comprises a cursor (15), fixed with respect to the nut (47), for indication of the disengagement torque; and the body (3) has an oblong axial window (49) through which the cursor (15) projects towards the outside of the body (3).
5. Dynamometric tool according to any one of claims 1 to 4, characterised in that it comprises a device for locking the regulation of the disengagement torque, allowing the handle (7) to be selectively fixed with respect to the body (3) or its rotation to be enabled, said locking device comprising a releasable means (71) for locking the second annular gearwheel (43) in its engaged axial position.
6. Dynamometric tool according to claim 5, characterised in that the locking means comprises a lever (71) which pivots relative to the handle (7) between a locked position and an unlocked position, said lever (71) having a portion (75) forming a cam bearing axially against the second gearwheel (43).
7. Dynamometric tool according to claims 3 and 6 in combination, characterised in that the threaded rod (31) comprises a drive portion (31C) around which is fitted the second annular gearwheel (43) so as to be capable of sliding axially and on which the locking lever (71) is pivotally mounted.
8. Dynamometric tool according to claim 7, characterised in that the pivot axis of the lever (71) is in the form of a transverse pin (33) which connects the threaded rod (31) and the handle (7) for conjoint rotation.
9. Dynamometric tool according to claim 7 or 8, characterised in that the locking means additionally comprises an intermediate bearing washer (44), axially displaceable on the drive portion (31C) and interposed between the second annular gearwheel (43) and the cam-forming portion (75) of the lever; and the resilient return means (45) is an axial spring bearing against the second annular gearwheel (43) at one of its ends and against said washer (44) at the other end.
10. Dynamometric tool according to any one of claims 6 to 9, characterised in that the lever (71) projects out from the handle (7) at the free end of said handle when it is in its unlocked position whereas it is essentially retracted within said handle (7) when it is in its locked position.
11. Dynamometric tool, especially a torque wrench, comprising a drive element, an outer hollow body (103) of elongate shape in which the drive element is mounted so as to be capable of pivoting, a means for axially bearing against the drive element, an axial spring which biases said bearing means towards the drive element and the compression of which determines a disengagement torque of the tool, and a handle (107) for regulation of the disengagement torque rotatably mounted on the body (103) for actuating a means for compressing the spring, characterised in that it comprises an annular gearwheel (141) having peripheral radial teeth which is fixed with respect to the body (103) at least for conjoint rotation, a finger (142) comprising a toothed sector (143) having complementary radial teeth and fixed with respect to the handle (107) for conjoint rotation, and a locking element (171) mounted on the handle (107) so as to be able to slide axially between a locking position, in which said teeth are mutually engaged and the locking element (171) prevents their disengagement so that the handle (107) and the body (103) are fixed to one another for conjoint rotation, and a disengagement position, in which the teeth of the toothed sector (143) can freely disengage themselves from the teeth of the annular gearwheel (141) by means of radial disengagement of said sector so that the handle (107) can be moved in rotation relative to the body (103), the teeth of the sector (143) and of the gearwheel (141) together defining stop notches of disengagement torque regulation; and in that it comprises a means (179) for resilient radial return of the toothed sector (143) into the position of engagement with the annular gearwheel (141).
12. Dynamometric tool according to claim 11, characterised in that it comprises a means (190) for resilient axial return of the locking element (171) into the locking position.
13. Dynamometric tool according to claim 11 or 12, characterised in that said resilient radial return means (179) is a toroidal ring of elastomeric material.
14. Dynamometric tool according to claim 11 or 12, characterised in that said resilient radial return means (179) is a metallic split ring.
15. Dynamometric tool according to any one of claims 11 to 14, characterised in that the locking element (171) is a ring coaxial with the body (103) and arranged radially outside the body and the toothed sector (143).
16. Dynamometric tool according to any one of claims 11 to 15, characterised in that the teeth of the annular gearwheel (141) and of the toothed sector (143) are teeth having inclined flanks.
17. Dynamometric tool according to any one of claims 11 to 16, characterised in that the toothed sector (143) is arranged to the outside of the annular gearwheel radially, the teeth of said sector (143) facing towards the inside whereas the teeth of said gearwheel (141) face towards the outside.
18. Dynamometric tool according to any one of claims 11 to 17, characterised in that said finger (142) additionally comprises an axially projecting leg (174) forming an axial bearing element, and a radial return (175) forming a radial positioning element.

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