Mechatronic torque wrench with click mechanism

Abstract

Mechatronic torque wrench comprising an elongated body having a handle (11) at one end and a tubular arm (12) at the opposite end, and, in a substantially intermediate position, a block (13) inside which there are electronic control circuits and an electronic processing unit. At the free end of such arm (13), there is a tool head (14) provided with a seat (15), in which a plurality of inserts (16) can be alternatively inserted, suitable for engaging the wrench with a corresponding type and / or size of mechanical part or element on which the wrench itself is intended to act. In such arm (13), there are sensor means for detecting the tightening conditions, such as for example sensors of the torque exerted on the mechanical part, and also a sensor for detecting the tightening angle. The wrench comprises a torque detection mechanism for torque wrenches, called "click", which is triggered when the desired torque value is reached during a joint tightening operation.

Description

[0001] Mechatronic torque wrench with click mechanism

[0002] The present invention relates to a torque wrench of the so-called mechatronic type.

[0003] Such type of wrench is a tightening tool that comprises a mechanical part and an electronic part. The mechanical part is represented by the click mechanism, which ensures that the desired tightening is reached through a “click signal”.

[0004] In particular, such mechanical torque detection mechanism provides the operator with the operation sensation of a force being applied, which is suddenly reduced when the tightening torque has reached a set / desired torque value. The electronic part monitors the tightening torque and / or angle and allows such data to be displayed. In this way, the operator, once the tightening is completed with the activation of the "click", which can be performed without the need to look at the display with the data, can now check the correct tightening from the displayed data. Furthermore, the data detected by the electronic part can be transmitted to an external electronic unit.

[0005] An example of such type of wrench is provided in patent EP3774184, which describes a wrench comprising a mechanism having a spring and releasable inserting means which disengage from a first position to a second disengaged position. Typically, the inserting mechanism disengages a cam element from a cam surface when the torsion of the arm accommodating the cam corresponds to (exceeds) the tightening torque to be exerted. One of the most important features for such types of wrenches is the repeatability of the click mechanism. In particular, the abovedescribed sensation of suddenly reduced force, when the desired tightening torque is reached, must occur substantially always at the same torque value.

[0006] The repeatability performance of the wrench is influenced by the alignment of the lever. In known-art wrenches, balls are used, which are placed between the lateral surface of the lever and the internal surfaces of the tube to centre the lever itself. Due to the process of manufacturing the tube, it is not possible to ensure tight tolerances due to plastic deformations, with resulting lower performance.

[0007] The Applicant has perceived that in order to ensure such repeatability of the tightening conditions, it is necessary to ensure that all elements of the kinematic system of the click mechanism remain aligned along the axis (longitudinal axis of the wrench).

[0008] Furthermore, the disengagement (the "click") in such types of wrenches results in an impact between the cam itself and the internal surface of the tube that constitutes the body or the arm of the wrench, in the area of the arm itself, where the torque (typically "strain gauges") and angle (typically gyroscopes) sensors are located. This can cause interference with the signal emitted by the sensors and with the resulting electronic measurement of torque and angle.

[0009] The present invention provides a solution to the above-mentioned problems by making a precise and balanced click mechanism that does not affect the measurements of the sensors of the electronic part of the torque wrench.

[0010] An aspect of the present invention relates to a torque wrench of the so-called mechatronic type having the features of claim 1.

[0011] Further objects and advantages of the present invention will become apparent from the following description and the attached drawings, provided solely by way of illustrative and non-limiting example, in which:

[0012] Figure 1 is a perspective view of a torque wrench according to the present invention;

[0013] Figure 2 is a longitudinal sectional view of the wrench of Figure 1 with the click mechanism highlighted in the resting or triggering waiting position according to the present invention;

[0014] Figure 3 is a longitudinal sectional view of the wrench of Figure 1 with the click mechanism highlighted in the triggering position according to the present invention;

[0015] Figure 4 is a front view example of the wrench of Figure 1 ;

[0016] Figure 5 is a view along section A-A of Figure 4 of the wrench according to the present invention;

[0017] Figure 6a is a perspective view of a torque wrench with the click mechanism exploded in a first embodiment of the present invention;

[0018] Figure 6b is a perspective view of a torque wrench with the click mechanism exploded in a second embodiment of the present invention;

[0019] Figure 7 shows a perspective view of the first centering pin according to the present invention;

[0020] Figure 8 shows an enlarged portion of the fork according to the present invention.

[0021] The mechatronic torque wrench according to the present invention comprises an elongated body (with respect to the X-axis in the figures) having a handle 11 at one end, a tubular arm 12 at the opposite end, and in a substantially intermediate position, a block 13 inside which there are electronic control circuits and an electronic processing unit.

[0022] Advantageously, the arm is tubular in shape but appears as a flattened tube having a height (along the Y-axis in the figures) greater than its width (Z-axis in the figures)

[0023] On such block, control buttons, electrical connection ports (for example, USB, Ethernet, etc.), possibly a display screen, and visual indicators (for example, LEDs) can be provided to indicate the operating status of the wrench, the progress of tightening, error signals, battery charge status, etc...

[0024] Through such ports or through a wireless connection, the wrench can be connected to external processing units. A wired connection can also be provided to supply external power.

[0025] At the free end of such arm 1 , there is a tool head 14 provided with a seat 15 in which a plurality of inserts 16 can be alternatively inserted. For example, each insert will be suitable for engaging the wrench with a corresponding type and / or size of mechanical part or element (screw, nut, etc.) on which the tool is intended to act.

[0026] Although for simplicity the inserts shown have similar size, elongated inserts or inserts with specially shaped arms can also be provided, as is known in the field.

[0027] The wrench comprises sensor means (for example, made with strain gauges arranged in the arm) for detecting the tightening conditions, such as for example sensors of the torque exerted on the mechanical part, as well as a sensor (for example, a gyroscopic sensor) for detecting the tightening angle.

[0028] The mechatronic wrench comprises therein a torque detection mechanism for torque wrenches, called "click", which is triggered when the desired torque value is reached during the joint tightening operation. The triggering causes, for a predetermined angle of the wrench, a “free” rotation in which no torque is exerted to the joint. Such triggering allows the operator to understand that the tightening has been completed. The electronic part of the wrench (sensors and electronic board of the wrench) confirms that the tightening has been completed with the above-mentioned signalling modes (LED, display, buzzer, etc...).

[0029] Such click mechanism comprises a fork 21, associated with the tool head 14, housed inside the tubular arm. In the embodiment illustrated, such fork is made in a single piece with the tool head. Furthermore, such fork, in the proximity of one of its ends, is hinged through a first transverse pin 22 inside the arm itself, so that it can rotate during tightening due to the force of the tool head on the joint, around such pin inside the arm, within the lateral size of the arm itself.

[0030] At the opposite end, such fork 21 is hinged to a central joint of a lever 24 through a second transverse pin 23.

[0031] One end of such lever is hinged, through a third pin 25, to a longitudinally sliding support 26 in the body of the wrench. Such sliding support 26 is in turn constrained to a spring 27 inserted into the handle of the wrench and fixed therein.

[0032] The spring is inserted preloaded into the handle thanks to a device 28 for adjusting the spring load, also placed in the handle.

[0033] The mechanism operates as follows: the preloaded spring 27 pushes the sliding support 26, which maintains the lever in the resting position (as shown in Figure 2). During tightening, the fork 21 is subjected to torsional stress and consequent rotation around the first pin 22. Such rotation causes the lever 24 to rotate around the second pin 23, which occurs only when the force exceeds the contrast given by the preloaded spring, moving such sliding support 26. When such force exceeds the set contrast value, which corresponds to the desired tightening torque, the lever rotates, releasing the rotation of the fork until the front end 241 of the lever itself strikes the internal surface of the tubular arm (as illustrated in Figure 3).

[0034] Such rotation of the fork 21 produces the sensation of triggering the mechanism and communicates to the operator that the tightening is completed, because the desired tightening torque value has been reached.

[0035] As previously indicated, the repeatability of the click mechanism is reliable to the extent that such movements are precise and balanced, particularly with respect to the longitudinal axis of the wrench.

[0036] According to a feature of the present invention, in order to achieve such balance, the mechanism comprises a first centering pin 3 placed transversely in the tubular arm and housed inside the fork 21. The pin is kept in position by two holes made in the tube; this ensures high positional precision for the pin.

[0037] Such pin comprises a cylindrical portion 31, which ensures that the lever is centered, and preferably also a conical portion 32, which acts as a contact point with the fork 21, ensuring a centered starting position also for the fork itself.

[0038] The coupling between the centering pin and the fork 21 is such as to allow relative movement between the fork and the pin only along the axis of the pin; for example, as illustrated in Figure 5, it allows the fork itself to slide up and down but not to move left or right, thus always maintaining a centered position.

[0039] Furthermore, the conical portion 32, when present, causes a unique resting or starting position for the fork. In this way, it is ensured that the (stable) starting point is always the same, thereby improving the repeatability of the click. For certain models of wrenches having an arm of reduced size (for example, wrenches rated at 25 Nm compared to longer wrenches rated at 85 Nm), in which the fork also has reduced size, a support dowel 33 for the fork, separated from the centering pin 3, has been inserted, placed near the pin itself.

[0040] Furthermore, in order to ensure the linearity of movement of the spring and the sliding support 26, the mechanism of the invention comprises a first centering element 34 of the spring 27, placed between the sliding support and the spring itself, and a second centering element 35 placed between the spring and the load adjustment device 28. Such centering elements 34 and 35 maintain the spring aligned (X axis) with all other elements of the click mechanism, thereby contributing to the repeatability of the click mechanism being ensured.

[0041] The click mechanism of the present invention causes the triggering and consequent impact of the lever on the tube. The click feeling is obtained with the impact of the front end 241 of the lever itself on the internal surface of the tubular arm, in a position close to the handle of the wrench and far from the area where the torque sensor is located, thus without affecting the torque reading. Typically, the torque sensor is placed in proximity to the tool head, or in an intermediate position of the arm.

Claims

CLAIMS1. Mechatronic torque wrench comprising:• an elongated body having a handle (11) at one end and a tubular arm (12) at the opposite end and in a substantially intermediate position, a block (13) inside which there are electronic control circuits and an electronic processing unit,• at the free end of said arm (1 ), a tool head (14) provided with a seat (15) in which a plurality of inserts (16) can be alternatively inserted, suitable for engaging the wrench with a corresponding type and / or size of mechanical part or element on which the wrench itself is intended to act,• in said arm (12) sensor means for detecting the tightening conditions, such as for example sensors of the torque exerted on the mechanical part,• a torque detection mechanism for torque wrenches called “click”, which is triggered when the desired torque value is reached during a joint tightening operation. characterized in that said click mechanism comprises• a fork (21), associated with the tool head (14) housed inside the tubular arm hinged in the arm itself, so that it can rotate during tightening due to the force of the tool head on the joint inside the arm,• said fork (21) being hinged to a central joint of a lever (24) capable of rotating due to the rotation of the fork, which atone end is hinged to a longitudinally sliding support (26) in the body of the wrench in turn constrained to a spring (27) inserted in the handle of the wrench,• said spring being preloaded in the handle thanks to a device (28) for adjusting the spring load also placed in the handle,• said rotation of the lever (24) occurs only when the tightening force on the fork exceeds the contrast given by the preloaded spring and therefore moves the sliding support (26),• a first centering pin (3) placed transversely in the tubular arm and housed inside the fork (21), such pin comprising a cylindrical portion (31) suitable for allowing relative movement between fork and pin only along the axis of the pin.

2. Wrench according to claim 1, wherein such centering pin comprises a conical portion (32), which acts as a contact point with fork (21), ensuring a centered starting position also for the fork itself.

3. Wrench according to claim 1, comprising a support dowel (33) for the fork placed near the centering pin (3).

4. Wrench according to claim 1, comprising a first centering element (34) of the spring (27) placed between the sliding support and the spring itself, and a second centering element (35) of the spring (27) placed between the spring itself and the load adjustment mechanism (28).

5. Wrench according to claim 1, wherein the mechanism is triggered by causing the click by the impact of the front end (241)of the lever (24) on the internal surface of the tubular arm, in a position close to the handle of the wrench and far from where the torque sensor is located.

6. Wrench according to claim 1, wherein the arm is tubular in shape but appears as a flattened tube having a height greater than its width.

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