FR2842450A1 - Dynamometric tool, especially torque wrench, has free contact end of switch for tool release detection device located inside curved body housing drive part of tool - Google Patents

Abstract

The switch (75) for the tool release detection device has a free end (75A) acting as a contact, located inside a curved body (3) housing the drive part (5) of the tool (1). The tool has a pivotable drive part mounted inside an elongated curved body, the pivoting action being generated by a pre- determined release torque. The tool release detection device comprises an electric circuit with a switch actuated by the drive part. A processor (79) is designed to utilise information provided by the state of the switch.

Description

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

  comprising a drive element, an elongated hollow body in which the drive element is mounted with the possibility of pivoting, the pivoting occurring for a predetermined tripping torque, and a device for detecting the tripping of the tool , said detection device comprising an electric circuit provided with a switching means actuated by the driving element, so that the state of said switching means is modified by the triggering of the tool, and of a unit processing, adapted to exploit the information relating to the state of said switching means. In known tools of the type described above, the triggering of the tool is detected by the closing of an electrical circuit whose switching means, actuated by the drive element, is located outside the body hollow. For this, the end of the drive element facing the inside of the tube is provided with a finger which projects outside the tube through a light made in the latter, the finger projects. actuating the movable element of the switch when tripping. The entire detection device is housed in a housing fixed externally to the body of the tool, towards a rear section of the drive element. Such a construction is not entirely satisfactory, owing to the fact that the projecting finger defines a protuberance at the periphery of the body of the tool, potentially hindering the introduction of the tool into

  a mechanical organ on which the operator intervenes.

  In addition, such a construction uses a miniature switch whose lifetime is relatively short, and which poses reliability problems when it is not waterproof, which is generally the case for

  current design switches.

  The object of the invention is to remedy these drawbacks and to propose a tool the trigger detection device of which does not increase the size in the foremost section of the tool, that is to say at the level of the drive element, and the switching means of which has an increased service life and reliability. To this end, in a dynamometric tool according to the invention, the switching means has one end

  free of contact placed inside the hollow body.

  According to other advantageous features of the invention - the processing unit is offset axially relative to the switching means, on the side of the tool opposite to the drive element, and is located at least partially at the outside of the hollow body; - The detection device comprises a printed circuit board; - The detection device comprises a display screen; and - the hollow body is made of a conductive material, and the electrical circuit includes a power source, a first terminal of which is connected to the hollow body, and a second terminal of which is connected to the switching means. Thanks to this latter arrangement, the electrical detection circuit is looped over mechanical components of the tool, which provides great simplicity.

  and high reliability of the detection circuit.

  According to yet other advantageous features of the invention: - the second terminal is connected to the switching means by means of an elongated conductor, and the hollow body has a groove in which said conductor is housed on most of its length; - The switching means is a flexible conductive strip; - Said blade is fixed to the hollow body by means of an insulating support, and extends at least partially between the internal surface of said hollow body and the external surface of the drive element, so that it s '' extends, at rest, without contact with the hollow body, the circuit then being open, and deforms under the action of the drive element when the tool is triggered, to a contact configuration on the hollow body, so as to close the electrical circuit; - The detection device comprises a housing fixed on the external periphery of the hollow body, and in which is housed at least partially the processing unit; and - said housing comprises two rigid half-shells assembled and fixed on the external periphery of the hollow body. An 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; - Figure 2 is an exploded perspective view of the key of Figure 1; - Figure 3 is a longitudinal sectional view of the key of Figure 1; - Figure 4 is a detailed perspective view of the flexible switching blade, and of a part of the detection device placed in the housing; - Figure 5 is a sectional view, on a larger scale, of Figure 3 along line 5-5; - Figure 6 is a longitudinal sectional view of the key of Figure 1, in a plane orthogonal to that of Figure 3, the key being in its normal operating configuration; - Figure 7 is an enlarged schematic sectional view in the direction 7-7 shown in Figure 6; Figure 8 is a view similar to Figure 6, the key being in the release configuration; and - Figure 9 is a view similar to Figure 7

  in the configuration of Figure 8.

  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, and a handle 7 for gripping the tool located

toward the back of the key.

  The tube 3 and, preferably, the head 5, are

metal parts.

  The key shown is of the production key type, that is to say of the type used in the production workshop to subsequently tighten a large number of identical bolting elements, to the same predetermined torque. For this type of tool, it is not necessary to readjust the tripping torque frequently. On such a key, the handle 7 is fixedly fitted on the tube 3, the latter being closed at its end, on the side of the handle 7 by a plug 9. As will be described later with reference to FIGS. 2 and 3, the tripping torque adjustment members are accessible by means of a tool

  inside the tube 3, after removing the plug 9.

  It is understood that the invention applies both to a so-called production key, as shown in the Figures, and to a torque wrench whose tripping torque is adjusted by other means, for example by rotation of the handle on the tube. The key shown 1 is provided, on a section adjacent to the handle, towards the front of the latter, with a housing 11, fixed on the periphery of the tube 3, and containing a part of the device for detecting the triggering of

  the tool, which will be detailed later.

  The key 1 further comprises a sheath 13 defined by a cylindrical sleeve, for example of plastic material, fitted in a fitted fashion on the tube 3 on a section

front adjacent to housing 11.

  We now refer to Figures 2 and 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 with play in the tube 3 and mounted with the possibility of pivoting on the tube 3, around a materialized ZZ axis

by a pin 27.

  The pin 27 passes diametrically through the articulation zone 23 and the tube 3 while being integral with the latter. The block 21 is designed to receive, from its front end, an actuating device (not shown). The latter is typically a reversible ratchet head by reversal, provided with a drive square

  on which a screwing sleeve fits.

  Note that in Figure 3, the X-Z section plane is assumed to be vertical and the X-X axis is assumed to be horizontal,

  for convenience of description. Key orientation

  shown in this Figure corresponds to the actuation of a screw or nut (not shown) whose axis is vertical. In the configuration for using the key as shown in FIG. 3, the following elements are arranged coaxially inside the tube 3, from rear to front, up to the rear end of the tail 25: - an externally threaded cylinder 31, provided with a drive form 33 facing the rear end of the tube, and the external thread of which cooperates with a thread

  internal formed on at least one rear section of the tube 3.

  Thus, the threaded cylinder 31 can be screwed or unscrewed inside the tube so as to be moved axially; - A spacer 35 formed, in the example shown, of an externally smooth hollow cylinder and of outside diameter slightly smaller than the inside diameter of the tube 3, so as to be able to slide freely inside the tube; - A compression spring 61 having a high stiffness, arranged coaxially inside the tube 3, and whose rear end bears on the front end of the spacer 35; - A plate 63 with ball 64, this plate being integral with the front end of the spring 61; a pusher 65 in the general form of a cylinder

  solid with a rear face resting on the ball 64.

  The plunger is designed to be able to slide axially while being guided in the tube 3, under the effect of the bias of the spring 61, transmitted by the plate 63 and the ball 64; - A cubic die 67 which is applied, at rest, on the bottoms of two recesses, one formed in the rear face of the tail 25, and the other in the front face of the pusher 65, these faces being faces vertical facing each other. The assembly formed by the pusher 65 and the die 67 defines

  an axial support means on the drive head 5.

  It is understood that the axial position of the threaded cylinder 31 determines the compression of the spring 61, and thus the axial force of support of the pusher 65 on the tail 25, by means of the die 67. When the maximum torque determined by the compression 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 strikes

the inner surface of the tube 3.

  The plug 9 has a threaded packing which engages in the rear end section of the tube 3, correspondingly tapped. The plug is screwed onto the tube so as to close the latter when the tool is in the configuration of use. When the user wants to adjust the key release torque, he must remove the plug 9, insert a screwing / unscrewing tool corresponding to the drive form 33 in the tube 3, and screw or unscrew the threaded cylinder 31 of way to

  adjust the compression of the spring 61.

  The torque wrench which has been shown comprises a trigger detection device, operating

  on the principle of switching an electrical circuit.

  This detection device will now be described in

reference to Figures 3 to 5.

  The detection device comprises an electrical circuit partially disposed on a printed circuit board 71, which is placed inside the housing 11, outside the tube 3. The printed circuit board 71 supports a power supply source 72 of the electrical circuit , this source being for example a battery. One of the terminals of the battery 72, for example the terminal "-", is electrically connected to the tube 3 (see FIG. 4) by means of an elastic conducting tab 73, of which a free end part 73A is made pressure on the outer surface of the tube. The second terminal of the battery 72, in this case the "+" terminal, is electrically connected to a switching means 75, by means of an elongated conductor, such as a wire 76. The flexible conductive blade 75 is secured by its base to an insulating base 77 fixed in a corresponding lumen of the tube 3, so that the blade 75 protrudes towards the inside of the tube. In the normal operating configuration of the key, that is to say before tripping, a free end portion 75A of the blade 75 extends without contact between the tail 25 and the internal surface of the tube 3,

  as shown in Figure 5.

  The electrical circuit of the detection device is further provided with a processing unit 79, such as an electronic component supported by the printed circuit board 71, adapted to take and exploit the electrical information circulating in the circuit, and relative in the state

  open or closed of the switching means 75.

  The processing unit 79 can be equipped with several functions, in addition to detecting the open or closed state of the switching means 75, in particular the increment and storage of a number of trigger cycles, and the preparation of '' an output signal that can be delivered to

  a device, such as a display or an alarm device.

  In the embodiment shown, the detection device comprises such a peripheral in the form of a display screen 81 connected to the processing unit 79 and to the battery 72 by means of a conductive sheet.

flexible 83.

  As shown in Figure 5, the housing 11 consists of two rigid half-shells llA, 11B

  complementary, fitting together by clamping the tube 3.

  The upper half-shell liA supports the screen 81 and presents a window for viewing this screen. The printed circuit board 71 and the elastic tongue 73,

  housed in the housing 11, are supported by the lower half-shell îlB.

  As can also be seen in FIG. 5, the elastic tongue 73 is fixed to the printed circuit board 71 by means of a screw 84, which also performs the rigid fixing of the card 71 in the half-shell.

lower islB.

  Referring again to Figure 3, we see that the outer surface of the tube 3, on an intermediate axial section, is provided with an axial groove 85 in

  which is housed the wire 76, over part of its length.

  This groove 85 and the section of the wire 76 which is housed therein are partly covered by the front section of the housing 11, and partly by the sheath 13. The sheath 13 ensures the fixing of the wire 76 in the groove 85, and protects access, from the outside, to the wire 76 and to the base 77. The sheath has a protuberance 87 facing the tube 3, which ensures the positioning and the fixing of the sheath 13 on the tube 3, by cooperating with a corresponding orifice

practiced in the tube.

  As can be seen, the arrangement of the switching means 75 inside the tube 3 makes it possible not to increase the size of the key in the front section of the key, that is to say over the entire length of the drive head 5. The switching means 75 being electrically connected to the battery 72 and to the processing unit 79 via an elongated conductor 76, the switching means 75 is located at an axial distance from the rest of the electrical circuit and of the housing 11, which define the largest peripheral size. The processing unit 79, housed in the housing 11, is offset axially relative to the switching means 75, towards the rear of the key. As already mentioned, it is important that the parts, such as the housing 11, which define the largest peripheral space on the key, are located as much as possible behind it so as not to interfere the introduction of the head

  5 drive in some mechanical parts.

  With reference to Figures 6 to 9, we will now

  describe the operation of the detection device.

  Figures 6 and 7 show the key in normal operating configuration, that is to say before triggering, the die 67 being engaged in the recesses of the rear face of the tail 25 on the one hand, and of the front face pusher 65 on the other hand. In this configuration, the user has not reached the maximum tightening torque or tripping torque preset by the compression of the spring 61. It can be seen in FIG. 7 that the free end part 75A of the member switching 75 extends without contact between the outer surface of the tail 25 and

the inner surface of the tube 3.

  The branch of the electrical circuit connecting the +/- terminals of the battery 72, passing through the switching means 75, which branch will be designated by the expression

  "the electrical circuit" is then opened.

  As shown in FIGS. 8 and 9, when the tripping torque is reached, the die 67 emerges from the recesses of the tail 25 and of the pusher 65, and the rear part of the tail 25 strikes the internal face of the tube 3. The free end part 75A of the switching means 75, as shown in FIG. 9, is then urged by the rear part of the tail 25 under pressure on the internal face of the tube 3. The electrical circuit of the detection device is then closed on the metallic mass piece constituted by the tube 3, and the processing unit 79 detects the passage of a current in the circuit, or more generally any electrical quantity capable of representing the open or closed state of the way

switching 75.

  When the key then returns to its normal operating configuration, the free end portion 75A of the switching means 75 returns to its rest position

  shown in Figure 7, under the effect of its elasticity.

  It is understood that the electrical information detected by the processing unit 79 is significant of the state of the switching means 75, that is to say of the occurrence of a phenomenon of triggering of the key. This electrical information can be used by the processing unit 79 in different forms so as to supply different indication members intended for the user, such as the display screen 81, an alarm (audible or visual), or other. Information can also be transmitted by various modes of communication to central storage facilities.

of data.

2 0

Claims (10)

  1. Tool, in particular wrench, dynamometric comprising a drive element (5), a hollow body (3) of elongated shape in which the drive element (5) is mounted with the possibility of pivoting, the pivoting occurring for a predetermined tripping torque, and a device for detecting the triggering of the tool, said detection device comprising an electrical circuit provided with a switching means (75) actuated by the drive element (5), so that the state of said switching means (75) is modified by the triggering of the tool, and of a processing unit (79), adapted to exploit the information relating to the state of said switching means (75) , characterized in that said switching means (75) has a free contact end   (75A) placed inside the hollow body (3).   2. Tool according to claim 1, characterized in that the processing unit (79) is offset axially relative to the switching means (75), on the side of the tool opposite to the drive element (5) , and is located at   at least partially outside the hollow body (3).   3. Tool according to claim 1 or 2, characterized in that the detection device comprises a printed circuit board (71).   4. Tool according to any one of the claims   1 to 3, characterized in that the detection device   includes a display screen (81).   5. Tool according to any one of the claims   1 to 4, characterized in that the hollow body (3) is made of a conductive material, and the electrical circuit comprises a power source (72), a first terminal (-) of which is connected to the hollow body (3) , and a second terminal (+) is   connected to the switching means (75).   6. Tool according to claim 5, characterized in that the second terminal (+) is connected to the switching means (75) via an elongated conductor (76), and the hollow body (3) has a groove (85) in which said conductor (76) is housed at least partially.   7. Tool according to any one of the claims   1 to 6, characterized in that the switching means (75) is a flexible conductive strip.   8. Tool according to claims 5 and 7 taken   assembly, characterized in that said blade (75) is fixed to the hollow body (3) by means of an insulating support (77), and extends at least partially between the internal surface of said hollow body (3) and the external surface of the drive element (5), so that it extends, at rest, without contact with the hollow body (3), the circuit then being open, and deforms under the action of the drive element (5) when the tool is triggered, until a configuration of contact on the hollow body (3),   to close the electrical circuit.   9. Tool according to any one of the claims   1 to 8, characterized in that the detection device comprises a housing (11) fixed on the external periphery of the hollow body (3), and in which is housed at least   partially the processing unit (79).   10. Tool according to claim 9, characterized in that said housing (11) comprises two rigid half-shells (liA, l1B) assembled and fixed on the periphery external of the hollow body (3).