FR2841491A1 - TOOL, PARTICULARLY KEY, DYNAMOMETRIC COMPRISING CLICKING TORQUE ADJUSTMENT MEANS - 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 drive element, an external hollow body of elongate shape in which the drive element is mounted with the possibility of pivoting, an axial support means on the drive element, an axial spring biasing said means support towards the drive element and the compression of which determines a trigger torque of the tool, and a handle for adjusting the trigger torque rotatably mounted on the body to actuate a compression means

spring.

  Torque tools of this type can

  including being keys, but still screwdrivers.

  Numerous tools of the aforementioned type are known in the prior art, in which the setting of the tripping torque is carried out continuously by rotation of a threaded element, this threaded element being devoid of

stop position.

  Such tools are not suitable for high precision of the setting of the tripping torque, the angular position of the adjusting handle being liable to vary during the operation of the tool. In addition, the precision of the adjustment is reduced because the operator has only one

visual sensation of adjustment.

  A first object of the invention is to remedy these drawbacks, and to propose a dynamometric tool in which the adjustment of the tripping torque can be carried out with great precision, with good sensations of use for the operator, not only visual but

also tactile and auditory.

  To this end, the tool comprises a first ring gear with peripheral teeth, secured to the body, a second ring gear with peripheral teeth with inclined sides, integral in rotation with the handle and complementary to the first, said second ring being able to slide axially between a clicked engaged position with the first ring and a position released from said first ring, the second ring being returned to the engaged position by an axial elastic return means, so that the different relative angular positions of the first and second rings define notches '' stop setting torque. According to other characteristics of the invention - the teeth of the first and second toothed rings are adapted so that, when engaged, a rotation of the second ring relative to the first produces, in a contact region of two complementary teeth, an axial reaction on the second crown tending to release it from the first, the intensity of the axial reaction being of the same order as that of the tangential reaction opposing the rotation, or greater; - The tool comprises a threaded adjustment rod arranged coaxially at least partially in the handle and linked in rotation to the handle, and a nut locked in rotation relative to the body and capable of axial translation in the body, said nut being engaged with the threaded rod so that a rotation of the handle drives the nut in axial translation relative to the body, and said nut bearing on one end of the thrust spring so as to compress it as a function of its axial position; and - the tool comprises a cursor indicating the tripping torque, integral with the nut, and the body has an oblong axial lumen, through which

  protrudes the cursor outward from the body.

  There are also known in the prior art (GB-A-2 306 363) torque wrenches, in which the handle is not only rotatably mounted on the outer hollow body, but also screwed into the hollow body, so that it can be actuated by a helical movement. 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-rotating 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, this second sleeve also being displaceable in axial translation relative to the handle over a length slightly greater than the height of the teeth, so as to selectively engage each other

  the teeth of the sleeves or release them from each other.

  The axial displacement of the second sleeve relative to the adjustment handle is obtained by the actuation in translation of an outer locking ring by

compared 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 adjustment of the release torque, while in the disengaged position of the teeth, the adjustment of the torque of

  trigger can be changed by the user.

  Such a locking device has the major drawback of the complexity due to the use of at least three parts, namely the two sleeves and the locking ring, all movable relative to the body of the key, which increases the complexity of

  design, parts manufacturing and assembly.

  Such a locking device therefore significantly increases the manufacturing costs

  torque wrenches provided with them.

  Another object of the invention is to remedy these drawbacks, and to provide a dynamometric tool equipped with a device for locking the adjustment of the tripping torque, the complexity and cost of which are reduced drastically, for a efficiency and

  identical or even improved precision.

  To this end, a dynamometric tool according to the invention comprises a device for locking the adjustment of the tripping torque making it possible to selectively fix the handle relative to the body or allow its rotation, said locking device comprising a releasable means for locking the second

  ring gear in its engaged axial position.

  According to other features of the invention, taken alone or in any technically conceivable combination: - the locking means comprises a lever pivoting relative to the handle between a locked position and an unlocked position, said lever having a portion forming a cam axial support on the second ring; - The threaded rod comprises a drive portion on which is fitted with the possibility of axial sliding the second toothed ring, and on which is pivotally mounted the locking lever; - The pivot axis of the lever is materialized by a transverse pin which secures in rotation the threaded rod and the handle; - The locking means further comprises an intermediate support washer, axially movable on the drive portion, interposed between the second toothed ring and the cam portion of the lever, and the elastic return means is an axial spring in support at one of its ends on the second ring gear, and at the other end on said washer; and - the lever protrudes from the handle at the free end of said handle, when it is in its unlocked position, while it is essentially retracted in said handle when it is in its locked position. A particular embodiment 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 the invention, the locking lever being in the unlocked position; - Figure 2 is a sectional view along 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 previous Figures; - Figure 4 is a similar detail view, still on a larger scale, showing the toothed rings; - Figure 5 is a detail view in perspective on a larger scale, of the cursor of the key of the previous Figures; - Figures 6 and 7 are views similar to Figures 1 and 3 respectively, the locking lever

being in the locked position.

  In Figure 1, there is shown a torque wrench according to the invention, the key having a

  longitudinal axis X-X, oriented from "rear" to "front".

  The key 1 which has been shown essentially comprises a tube 3 of generally cylindrical shape, defining an external hollow body, a head or drive element 5 towards the front of the key, a handle 7 for gripping the tool and setting the tripping torque, located towards the rear of the key. The key 1 further comprises, in an intermediate region, a fixed ring 9, integral with the tube 3, as well as a fixed guard 11, integral with the ring 9 and fitted

  on a front section of the handle 7.

  The key 1 is further provided with a graduations support 13, in the form of a flat lamella and fixed on the tube 3, and of a cursor 15 (Figures 2 and 3) which can move axially on the graduated blade 13 so

  indicate the value of the tripping torque.

  The tube 3 and the head 5 are preferably metal parts. As shown in FIG. 2, the drive head 5 is a part which comprises a front block 21 projecting from the front of the tube 3, an intermediate articulation zone 23, and a rear tail 25 fitted into the tube 3 with clearance and mounted with the possibility of pivoting on the tube 3 about an axis ZZ materialized by a pin 27. In this Figure, the XZ plane of section is assumed to be vertical and the axis XX is assumed to be horizontal, for the

convenience of description.

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

screwing sleeve.

  The pin 27 passes diametrically through the articulation 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 nut (not

  shown) whose axis is vertical.

  On the rear part of the tube 3 is coaxially mounted the handle 7, rotating around the horizontal axis X-X. The handle is hollow internally so as to be fitted onto the tube 3. It is integral with an internal threaded rod 31 coaxial, the latter being secured to the handle 7 by a pin 33 passing through a rear end orifice of the rod threaded 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 (for example hexagonal or square) in which

the hole is made.

  We now refer 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 of the threaded rod, bearing on the sleeve 35.

  On the rear section 31C is fitted a movable sleeve 39 of complementary internal shape, this movable sleeve 39 thus being made integral in rotation with the threaded rod 31 and capable of sliding on the latter at

  inside the axial internal recess of the handle 7.

  The fixed sleeve 35 and the movable sleeve 39 are provided with respective complementary toothed rings 41, 43, the teeth of the crowns 41, 43 being complementary, and turned opposite one another. The teeth of the crowns 41, 43 extend so

  peripheral and are oriented axially (Figure 4).

  A washer 44 freely mounted in axial translation on the drive section 31C is interposed between the movable crown 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 crown 43, and by its second end on the washer 44, so as to axially urge the movable crown 43 in a position, in which the toothed crowns 41 and 43

are mutually committed.

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

same order.

  We understand that we can thus achieve a so-called "clicking" 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 driven integrally in rotation, so that the ring gear 43, alternately undergoes axial recoil movements, the return force of the spring 45 being then overcome, and in advance, under the effect of the pushing force of the spring 45. The cooperation of the teeth of the crowns 41, 43 in different angular positions of the movable crown 43 relative to the fixed crown 41, defines stops in rotation of the handle 7 by

compared to 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 nut 47

  relative to the tube 3, inside the latter.

  Towards the rear of the tube 3 is made a light

oblong 49 extending axially.

  The cursor 15, which has been shown alone in FIG. 4, is rigidly fixed to the nut 47 by making

  protruding through the oblong lumen 49.

  As can be seen in FIG. 5, the cursor 15 essentially consists of a ring 51 in an arc of a circle and an axial arm 52, the free end edge 53 opposite to the ring 51 indicates, by superposition with the graduations of the graduated blade 13, the tripping torque adjusted by rotation of the handle 7. The ring 51 adjusts on the periphery of the nut 47. A stud 55 projecting radially from the internal face of the ring 51 s inserts 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 in abutment

  on the rear face of a pusher 65.

  The pusher 65 is of generally cylindrical shape and can slide axially while being guided in the tube 3,

  under the effect of spring stress 61.

  The rear face of the tail 25 and the front face of the pusher 65 are vertical faces facing one another, each of which has a recess. A cubic die

  67 applies, at rest, on the funds of these recesses.

  The assembly formed by the pusher 65 and the 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 force for pressing the pusher 65 on the tail 25, by means of the die 67. When the maximum torque determined by the compression of the spring 61 is reached, the die 67 tilts and causes the pusher to move back. The tail 25, by pivoting around the pin 27, then comes to

  contact of the inner surface of the tube 3.

  A lever 71 is pivotally mounted on the rear end of the drive section 31C of the threaded rod 31, around a transverse axis materialized by the pin 33. The lever 71 has an actuating part 73 which, in the position of the lever shown in Figures 1 to 3, projects axially from the rear of the handle 7. It further comprises a block 75 forming a cam, turned towards the washer 44 and bearing thereon by its cam surface . The lever 71 forms, with the sleeves 35, 39 and the washer 44, a releasable device for locking the adjustment of the tripping torque, as will be

now explained.

  In the position of the lever 71 shown in FIGS. 1 to 3, that is to say in the unlocked position, the washer 44 is separated axially from the movable sleeve 39 by a distance D greater than the height of the teeth of the crowns 41, 43, so that the movable sleeve 39 can undergo variations in axial position on the drive section 31C, under the effect of the rotation of the handle 7. Thus the handle can be freely actuated in rotation by the user, so as to adjust the compression of the spring 61 and the value of the tripping torque. When the user wishes to lock the setting of the tripping torque to use the tool without fear of disruption, he operates the lever 71 by pressing the operating part 73 downward, so as to subject the lever to a quarter turn 71. The lever is located 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 rests on 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 crowns 41, 43 (the "height" s' means the active height of the teeth, i.e. the

height of the teeth).

  It is understood that, in this locked position of the lever 71, the return spring 45 is strongly compressed and produces its maximum stressing force on the toothed rings 41, 43 in their engaged position. The movable crown 43 is limited, in its axial rearward movement on the drive section 31C, by the washer 44 and the block 75. In this position, the movable crown 43 cannot be extracted from its position of engagement with the fixed crown 41, and consequently the handle 7 can no longer be rotated to modify the tripping 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 into the handle 7. This arrangement allows an operator to use the tool, without feeling 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 with reference to Figures 1 to 3, which indicates to the operator, visually and tactile , that the setting of the tripping torque is not locked. As can be seen in particular in FIG. 6, the shape of the operating part 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. It is understood that the invention applies in a particularly suitable manner 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 achieve, for a dynamometric tool, a function of locking the adjustment of the tripping torque, by means of a device whose constituent parts have simple relative movements,

  as well as low manufacturing and assembly costs.

  The invention performs the function of locking the setting of the tripping torque from a cogwheel assembly which provides a clicking setting. This type of ratcheting adjustment provides the advantage of a large number of angular stop positions, therefore great precision of the adjustment, as well as good feelings of use for the operator, the passage of the notches being audible and

felt by the user.

  The invention therefore makes it possible to combine the advantage of a great sensitivity of the adjustment and that of a great

  simplicity of implementation of the locking function.

Claims (10)

  1. Tool, in particular wrench, dynamometric comprising a drive element (5), an external hollow body (3) of elongated shape in which the drive element (5) is mounted with the possibility of pivoting, a means (65 , 67) for axial support on the drive element, an axial spring (61) urging said support means (65, 67) towards the drive element (5) and the compression of which determines a torque of triggering of the tool, and a handle (7) for adjusting the triggering torque rotatably mounted on the body (3) to actuate a means (47) for compressing the spring (61), characterized in that it comprises a first ring gear (41) with peripheral teeth with inclined sides, integral with the body (3), a second ring gear (43) with peripheral teeth, integral in rotation with the handle (7) and complementary to the first, said second ring (43 ) able to slide axially between a clicked engaged position with the first ring (41) and a position released from said first ring (41), the second ring (43) being returned to the engaged position by means (45) of axial elastic return, so that the different relative angular positions of the first (41) and second (43) crowns define   stop stops for setting the tripping torque.   2. Torque tool according to claim 1, characterized in that the teeth of the first (41) and second (43) toothed rings are adapted so that, when engaged, a rotation of the second ring (43) relative at the first (41) produces, in a contact region of two complementary teeth, an axial reaction on the second ring (43) tending to release it from the first (41), the intensity of the axial reaction being of the same order than that of the reaction   tangential opposing rotation, or higher.   3. Torque tool according to claim 1 or 2, characterized in that it comprises a threaded adjustment rod (31) arranged coaxially at least partially in the handle (7) and linked in rotation to the handle (7), and a nut (47) locked in rotation relative to the body (3) and capable of axial translation in the body (3), said nut (47) being engaged with the threaded rod (31) so that a rotation of the handle (7) drives the nut (47) in axial translation relative to the body (3), and said nut (47) bearing on one end of the thrust spring (61) of   so as to compress it according to its axial position.   - 4. Torque tool according to claim 3, characterized in that it comprises a cursor (15) for indicating the tripping torque, integral with the nut (47), and the body (3) has an axial oblong lumen (49), through which the cursor projects   (15) towards the outside of the body (3).   5. Torque tool according to any one of   Claims 1 to 4, characterized in that it comprises a   locking device for adjusting the tripping torque making it possible to selectively fix the handle (7) relative to the body (3) or authorize its rotation, said locking device comprising a releasable means (71) for locking the second toothed ring (43 ) in its engaged axial position.   6. Torque tool according to claim 5, characterized in that the locking means comprises a lever (71) pivoting relative to the handle (7) between a locked position and an unlocked position, said lever (71) having a portion ( 75) forming support cam   axial on the second ring (43).   7. Torque tool according to claims 3   and 6 taken together, characterized in that the threaded rod (31) comprises a drive portion (31C) on which is fitted with the possibility of axial sliding the second toothed ring (43), and on which is mounted   pivot the locking lever (71).   8. Torque tool according to claim 7, characterized in that the pivot axis of the lever (71) is materialized by a transverse pin (33) which secures in rotation the threaded rod (31) and the handle (7). 9. Torque tool according to claim 7 or 8, characterized in that the locking means further comprises an intermediate support washer (44), axially displaceable on the drive portion (31C), interposed between the second ring gear (43) and the cam portion (75) of the lever, and the elastic return means (45) is an axial spring bearing at one of its ends on the second toothed ring (43), and at   the other end on said washer (44).   10. Torque tool according to any one   claims 6 to 9, characterized in that the lever   (71) protrudes from the handle (7) at the free end of said handle, when it is in its unlocked position, while it is essentially retracted into said handle (7) when it is in its locked position .