FR2841492A1 - Limited torque tool, especially a wrench, has adjustable interlocking components on body and handle for setting required torque level - Google Patents

Abstract

The tool, especially a torque wrench, consists of a drive member (5) able to turn inside a hollow outer body (3) with a spring, a handle (7) and adjustable interlocking components. The latter are in the form of a fixed ring (9) on the body and an adjustable one (11) on the handle with interlocking teeth (79, 99) that are set to give the required torque. The tool is rotated by the handle until the required torque is achieved by the drive member, when the interlocking teeth disengage.

Description

The present invention relates to a tool, in particular a torque wrench

  comprising a drive element, an external hollow body of elongated 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, a trigger torque adjustment handle rotatably mounted on the body to actuate a means of compression of the spring, and a locking device setting the tripping torque to selectively fix the

  handle relative to the body or allow its rotation.

  Already known in the prior art (GB-A-2 306 363) torque wrenches of the aforementioned type, 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 in 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. In addition, the two sleeves are housed inside the handle, which further increases the complexity of design, manufacturing of parts and

assembly.

  Such a locking device therefore significantly increases the manufacturing costs

  torque wrenches provided with them.

  A main 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 manufacture of which are drastically reduced, for a

  identical and even improved efficiency and precision.

  To this end, in a dynamometric tool according to the invention, the locking device comprises a first locking member fixed relative to the body, and a second complementary locking member, linked in rotation to the handle and capable of being moved axially. relative to the handle, between a position of engagement with the first locking member in which the two locking members are integral in rotation, and a position released from said first locking member in which said first locking member is free to rotate in relation to this audit

second locking member.

  According to other characteristics of the invention, taken alone or in any technically conceivable combination: - the locking device further comprises an elastic return member acting axially to urge the second locking member towards its position of engagement with the first locking member; - at least one of the two locking members is a toothed ring with axially oriented peripheral teeth, while the other locking member comprises at least one complementary tooth projecting axially towards the teeth of the ring - the two members locking are toothed rings with complementary peripheral teeth oriented axially towards one another; - 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 product, in a contact region of two complementary teeth, an axial reaction on the second ring tending to release it from the first, the intensity of the axial reaction being very low compared to that of the tangential reaction opposing the rotation; - The second locking member is a toothed ring having internally axial slide elements, and the handle externally has complementary axial slide elements, making it possible to secure in rotation and guide in axial translation the second locking member on the handle; the tool comprises a threaded adjustment rod disposed at least partially coaxially 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 rod threaded 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; - The tool comprises a cursor indicating the tripping torque, integral with the nut, and the body has an oblong axial lumen, through which the cursor projects outwards from the body; - The body is integral with a first toothed ring with axial peripheral toothing, the threaded rod is integral in rotation with a second toothed ring with axial peripheral teeth complementary to the first, said second crown being able to slide axially on the threaded rod between a position engaged with the first crown and a position released from said first crown, and the second crown is returned to the engaged position by an axial elastic return means, so that the different relative angular positions of the first and second crowns define notches trip torque adjustment stop; and - 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 product, 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. A particular embodiment of the invention will now be described in more detail with reference to the accompanying drawings, in which: - Figure 1 is an elevational view of a torque wrench according to the invention, the movable ring being in clear position of the fixed ring; Figure 2 is a top view of the key of Figure 1; - Figure 3 is a sectional view along line 3-3 shown in Figure 2; - Figure 4 is a detail view of Figure 3, on a larger scale, showing the toothed rings; - Figure 5 is a detailed perspective view, on a larger scale, of the key cursor of the previous Figures; - Figure 6 is a detailed perspective view, on a larger scale, of the fixed ring of the key of Figures 1 to 3; - Figure 7 is a detailed perspective view, on a larger scale, of the key adjustment handle of Figures 1 to 3; - Figure 8 is a detailed perspective view, on a larger scale, of the movable ring for locking the key of Figures 1 to 3; and - Figure 9 is a view similar to Figure 1, the

  movable ring being in the engaged position.

  In Figure 1, there is shown a torque wrench according to the invention, in a plane which will be considered as a vertical plane, the key having a longitudinal axis X-X horizontal, 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 toothed ring 9, integral with the tube 3, as well as a movable toothed ring 11, mounted on the handle 7. As will appear better in FIG. 2, the key 1 is further provided with a graduations support 13, in the form of a flattened lamella and fixed on the tube 3, and of a cursor 15 which can move axially on the graduated blade 13 so as to indicate the value of the torque trigger. The tube 3 and the head 5 are preferably metal parts. As shown in FIG. 3, 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 play and mounted with the possibility of pivoting on the tube 3 around an axis ZZ materialized by a pin 27. The block 21 has, from its front end, an attachment 29, in which can be nested and fixed a actuator (not shown). The latter is typically a reversible ratchet head by reversal, provided with a drive square on which

fits 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 Figures 1 to 3 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 (not shown) passing through an orifice 33 at the end rear 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 portion 31C of polygonal cross section (hexagonal or square for example) in which

hole 33 is made.

  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 peripherally and are oriented axially (see

Figure 4).

  An axial spring 45 of low stiffness is interposed between the movable sleeve 43 and a rear transverse wall 46 of the internal recess of the handle 7, so as to axially urge the movable sleeve 43 in a position, in which the toothed rings 41 and 43

are mutually committed.

  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.

  Of course, the means for carrying out the "clicking" adjustment are optional in the implementation.

  a locking device according to the invention.

  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 slider 15, which has been shown alone in FIG. 5, 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 tube 3. A stud 55 projecting radially from the internal face of the ring 51 is inserted in a peripheral notch 57 (Figure 3) of 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 cursor 15, and consequently that of the nut 47, is blocked during 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.

  In Figure 6, there is shown on a larger scale the fixed ring 9 alone. This fixed ring 9 is fixed to the tube 3 by fitting and by cooperation of pins 71, projecting radially from the inside of the ring 9, with corresponding slots made in the tube 3. The fixed ring 9 essentially consists of a first generally cylindrical sleeve 73 of circular section, having an axial window 75 which defines a passage for the cursor 15. On an axial portion of the

  window 75, this is closed by the graduated strip 13.

  When the ring 9 is assembled on the tube 3, as seen in FIG. 3, the axial arm 52 of the cursor is superimposed on the graduated strip 13, and the cursor 15 can be

  move axially in window 75.

  The ring 9 further comprises a second sleeve 77 integral with the sleeve 73 and of larger diameter. The second sleeve or outer sleeve 77 extends coaxially to the inner sleeve 73, with an opening provided opposite the window 75. The two sleeves 73, 77

  are connected by a connecting ring 78.

  On at least part of its front peripheral edge, the outer sleeve 77 is provided with axial teeth 79, the point of which faces towards the rear of

  the tool when the fixed ring is assembled on the tube 3.

  The fixed ring 9 is preferably made of a

  piece, molded plastic.

  In FIG. 7, the adjustment handle 7 is shown in perspective, alone, on a scale greater than

that of Figure 3.

  The handle 7 is preferably a single piece of molded plastic. It has a generally cylindrical, hollow shape, as seen in FIG. 3, with a slightly curved portion and widened towards the rear, so as to facilitate gripping by a user. This curved part is formed on a rear section called grip 7C. The handle 7 also has a front cylindrical section 7A of smaller diameter, connected to the rear section 7C via an intermediate section 7B of intermediate diameter. On a part of the intermediate section 7B are formed, over the entire periphery, axially elongated bars 81, which define first sliding connection members between the handle 7 and the movable ring 11. The bars 81

  each have a front face 83 of axial stop.

  Referring again to Figure 3, the handle 7 is fitted on the fixed ring 9, and carries, by a rear portion 84 of the inner wall defining its inner recess, directly on a rear portion

outside of tube 3.

  In Figure 8, there is shown on a larger scale than in Figure 3 the locking ring 11 alone, in perspective. The movable ring 11 has a generally frustoconical outer shape whose base of larger diameter is turned towards the rear of the tool. The movable ring 11 is formed with a coaxial bore 91 of generally cylindrical shape and of diameter corresponding to the diameter of the intermediate section 7B of the handle 7, so that the movable ring 11, mounted on the intermediate section 7B of the handle 7, can slide axially on this intermediate section. The internal face of the bore 91 is formed with a peripheral aliasing defining a succession of axial bars 93 and axial notches 95, said notches 95 being intended to cooperate with the bars 81 of the handle 7 to define an axial slide connection. This sliding link allows the sliding and the guiding of the ring

movable there on the handle 7.

  The notches 95 have a notch bottom 97 defining with the front face 83 of the bars 81 a stop in axial translation towards the rear of the movable ring 11 relative to the handle 7. The base of smaller diameter the frustoconical mobile ring 11 is provided, over its entire periphery, with axial teeth 99 complementary to the teeth 79 of the fixed ring 9, and turned towards the front of the tool when the mobile ring 11 is mounted on the

handle 7.

  Referring again to Figure 3, it should be noted that the movable ring hi is biased towards the front section 7A of the handle by an axial spring 101 of return

  the movable ring 1h towards the fixed ring 9.

  It is understood that, thanks to the axial slide connection formed by the bars 81 and the notches 95, the ring hi is linked in rotation with the handle 7 and can slide on the latter between a position released from the fixed ring 9, as shown in Figure 1, and a position engaged with the fixed ring 9, as shown in the

Figure 9.

  In the released position obtained by voluntary action of the user, position visible in Figure 1, the movable ring and the handle 7 can rotate together around the axis XX relative to the tube 3, which allows the adjustment of the compression of the spring 61 (that is to say the setting of the release torque, as has been seen previously). To carry out this adjustment, the operator must turn the handle 7 while keeping the movable ring il released from the fixed ring 9 against the effect of the spring 101, until displayed by means of the cursor 15 on the graduated strip. 15 the desired tripping torque value. When the operator considers that he has set the tripping torque to its desired value, he releases the movable ring 15, which, under the effect of the spring 101, is

  pushed forward in engagement with the fixed ring 9.

  The bars 81 and the notches 95 are designed

with a slight play in rotation.

  The complementary teeth 79, 99 can be provided so that an effort, even significant, to actuate the handle 7 in rotation while the complementary teeth 79, 99 are in engagement, does not allow the disengagement of the teeth and thus the unlocking of the adjustment locking device. For this, the teeth 79, 99 are provided with lateral faces at a slight inclination relative to the axis of rotation. Thus a rotation of the movable ring relative to the fixed ring produces, in a contact region of two complementary teeth, an axial reaction on the movable ring tending to disengage it from the fixed ring, very weak in front of the

  tangential reaction opposing rotation.

  More generally, the inclination of the faces of the teeth 79, 99 can be chosen so that the forced unlocking is carried out with a predetermined torque of the user on the handle. This predetermined torque would correspond to a limit torque for damage or destruction of the mechanical locking members in the event of the user forcing the handle and in the absence

  unlocking action on the ring 11.

  Conversely, the teeth of the toothed crowns 41, 43 are designed so that the disengagement of the crowns, from an engaged position, is effected by a low, almost insensitive 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.

  It is understood that the invention applies in a particularly suitable manner to a torque wrench, as described above, but it could also be suitable for

  other torque tools, such as screwdrivers.

  In the case of a screwdriver, the tightening force during normal use of the screwdriver is taken up by the fixed and mobile rings, the latter then being engaged. The invention which has just been described makes it possible to carry out, for a dynamometric tool, a function for locking the adjustment of the triggering torque, by means of a device whose constituent parts have simple relative movements, as well as low costs. manufacturing and assembly. In particular, these parts, namely the handle, the fixed ring, and the movable ring, can be mounted externally on the tube, therefore easily assembled and possibly disassembled. They can all be made of plastic, so

  with low production costs.

2 0

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, a handle (7) for adjusting the trigger torque rotatably mounted on the body (3) to actuate a means (47) for compressing the spring (61), and a device for locking the adjustment of the torque release enabling the handle (7) to be selectively fixed relative to the body (3) or to allow its rotation, characterized in that the locking device comprises a first locking member (9) fixed relative to the body (3), and a second complementary locking member (11), linked in rotation n to the handle (7) and capable of being moved axially relative to the handle, between a position of engagement with the first locking member (9) in which the two locking members are integral in rotation, and a position disengaged from said first locking member (9) in which said first locking member (9) is free to rotate relative to said second locking member lock (11).   2. Torque tool according to claim 1, characterized in that the locking device further comprises an elastic return member (101) acting axially to urge the second locking member (11) towards its position of engagement with the first locking member (9).   3. Torque tool according to claim 1 or 2, characterized in that at least one of the two locking members (9, 11) is a toothed ring with axially oriented peripheral teeth, while the other locking member comprises at minus one complementary tooth in   axial projection facing the teeth of the ring.   4. Torque tool according to claim 3, characterized in that the two locking members (9, 11) are toothed rings with peripheral teeth   complementary axially oriented towards each other.   5. Torque tool according to claim 4, characterized in that the teeth (79, 99) of the first (9) and second (11) toothed rings are adapted so that, when engaged, a rotation of the second ring (11) relative to the first (9) produces, in a contact region of two complementary teeth (79, 99), an axial reaction on the second ring (11) tending to release it from the first, the intensity of the axial reaction being very weak compared to that of the tangential reaction opposing rotation.   6. Torque tool according to any one of   claims 3 to 5, characterized in that the second   locking member (11) is a toothed ring having internally elements (95) of axial slide, and the handle (7) has externally complementary elements (81) of axial slide, making it possible to secure in rotation and to guide in axial translation   the second locking member (11) on the handle (7).   7. Torque tool according to any one of   Claims 1 to 6, characterized in that it comprises a   adjusting threaded rod (31) disposed 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) so as to compress it in function from its axial position.   8. Torque tool according to claim 7, 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).   9. Torque tool according to claim 7 or 8, characterized in that the body (3) is integral with a first toothed ring (41) with axial peripheral toothing, the threaded rod (31) is integral in rotation with a second ring gear (43) with axial peripheral toothing, complementary to the first, said second ring (43) being able to slide axially on the threaded rod (31) between a position engaged with the first ring (41) and a position released from said first ring (41), and the second ring (43) is 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) rings define notches '' torque adjustment stop trigger.   10. Torque tool according to claim 9, 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.