The present invention relates to an electromechanical digital torque wrench.

In particular, the present invention relates to a torque wrench equipped with a mechanical snap-release mechanism piloted by an electromagnet, and suitable for being advantageously used for the controlled tightening of blocking devices such as screws, nuts, bolts and the like, with a prefixed tightening torque, digitally set and controlled.

In order to guarantee a correct and accurate homogeneity of the tightening load in blocking devices of mechanical equipment, torque wrenches of the known type are adopted, comprising a substantially tubular body, equipped with a handle, to which a insertion mechanism is applied in correspondence with an end of the same body, whose cavity is suitable for being coupled with the blocking device to be tightened.

An actuator group that is activated when the prefixed tightening torque is reached, is housed inside the tubular body, connected to mechanical lever means.

At present, among the numerous types of known torque wrenches, some of the most widely used are those provided with an actuator group defined by a snap- mechanism, and also those in which there is a digital transformation system of the torque exerted into an electrical signal to be visualized on a specific control display.

In known snap torque wrenches, when the pre- established torque value or target has been reached, the above-mentioned mechanism is suitable for allowing a further limited rotation action of the tubular body in the tightening direction without this supplementary action having any effect on the blocking device, thus emitting a clear acoustic and sensitive signal - a mechanical snap due to the change in state of the internal lever mechanisms facilitated by spring means - which can be easily heard and perceived by the user.

Snap wrenches are therefore extremely easy to use and have a high productivity, they are very robust and reliable but have a limited accuracy, in particular due to the sum of the intrinsic tolerances of the lever mechanisms and spring means.

Furthermore, it is not possible to extend the functionalities of snap wrenches.

In digital torque wrenches, when the pre- established torque value or target is reached, this is optimally visualized on the control display with high precision, also with acoustic signals (buzzers) and/or vibrations and/or luminous Leds that can be perceived by the user.

Digital wrenches are therefore extremely accurate, they also have the possibility of programming and memorizing various tightening data, and there is a high possibility of extending their functionalities.

With these digital wrenches, however, the tightening is restricted to the sensitivity of the user, in the sense that he must always pay attention to the signals on the display so as not to exceed the preset values, thus creating a low productivity.

An objective of the present invention is therefore to solve the problems of the known art indicated above.

In particular, an objective of the present invention is to provide a torque wrench capable of being extremely accurate and effective, easy and rapid to use, and highly practical.

A further objective of the present invention is to provide a torque wrench having a high extension degree of the functionalities, and with the possibility of memorizing and transferring the tightening values effected.

The structural and functional characteristics of the present invention and its advantages with respect to the known art will appear even more evident from the following claims, and in particular from the following description, referring to the enclosed drawings, which show the schematizations of a preferred but non- limiting embodiment, and a variant, of the torque wrench object of the invention, in which:

- figure 1 represents a view of a first embodiment of the torque wrench, object of the invention, in a partially sectional view and with parts that have been removed for the sake of clarity;

- figure 2 is a front view on an enlarged scale of a detail of the wrench of figure 1;

- figure 3 is a partially sectional front view on an enlarged scale of the detail of the wrench of figure 2;

- figures 4A and 4B are respective front views of the detail of figure 2 in two different operative positions ;

- figure 5 represents a partially sectional front view with parts that have been removed for the sake of clarity, of a detail of a variant of the torque wrench, object of the invention;

- figure 6 is a view on an enlarged scale of the detail of the wrench of figure 5.

With reference to the enclosed figures from 1 to 6, a torque wrench suitable for being used for the controlled tightening of blocking devices (known and not illustrated) with a prefixed tightening torque, is indicated as a whole with C.

The wrench C is of the type comprising a tubular body T, which is equipped with a handle (known and not illustrated) and, in correspondence with an end of the body T itself, carries a insertion mechanism (also known and not illustrated) , whose cavity is suitable for being coupled with the blocking device to be tightened.

An actuator group G that can be activated when the prefixed and preset tightening torque is reached, is housed inside the tubular body T, connected to mechanical lever means L suitable for exerting the tightening torque.

According to what is illustrated in figures 1 and

2, the group G comprises a trolley 3 defined by an element substantially having a flat trapezoidal section with rounded edges, whose two opposite side ends K' and K" (with K' connected to the lever means L) support respective rolls 2' and 2" rotatable in neutral around respective fulcra f and f" .

The trolley 3 is suitable for cooperating with a substantially parallelepiped fixed block B, which has a flat edge 1 tilted with respect to the vertical by a certain angle a on which the roll 2" of the same trolley 3 is suitable for rolling m contact.

According to what is illustrated in figures 2 and 3, the block B also carries a pendulum element 4, which has its fulcrum on the block B itself around a pin PB situated in correspondence with a corner of the same block B opposite the edge 1, and is connected to a movable pin or stem 6 of an electromagnet 5, also forming part of the group G positioned inside the body C.

Elastic return spring means 7 are also present.

According to what is illustrated in figure 4A, the group G is normally in a condition of equilibrium, stable also when loaded, defined by the trolley 3 resting by means of the roll 2" on the tilted flat edge 1 of the block B, and by the pendulum element 4 whose end or tooth 4a blocks the end K" of the trolley 3, keeping the same trolley 3 in a substantially fixed horizontal position and with both rolls 2' and 2" in contact with the internal edge of the tubular body T.

In other words, the tilted edge 1 of the block B is suitable for breaking up the thrust force of the roll 2" against the block B into two components, one directed horizontally and parallelly to the longitudinal axis of the body T of the wrench C, whereas the other, having a minimum value, is directed vertically and transversally to the axis of the wrench C and is opposed to the pendulum element 4 which is withholding the trolley 3.

When in use, once the preselected tightening torque has been reached, for example, preferably previously preset on a digital measurement and control display present on the wrench C itself, in a known way and therefore not illustrated, the electromagnet 5 is activated to attract the pendulum element 4 and rotate the same element 4 around the pin PB so as to release - the tooth 4a from contact with the above end K" of the trolley 3, whose roll 2" can therefore slide rapidly along the tilted edge, consequently causing the trolley 3 itself to be released, moving upwards (operative change-of state position of figure 4B) , thus causing the movement of the levers L which definitively blocks the tightening action of the blocking devices.

According to the variant envisaged and illustrated in figures 5 and 6, the trolley 3 is suitable for cooperating with a substantially parallelepiped fixed block Ba having a vertical flat edge la on which the roll 2" of the same trolley 3 is suitable for rolling in contact .

The block Ba also carries a pendulum element 8, which has its fulcrum on the same block Ba around a pin PBa situated in correspondence with a corner of the same block Ba opposite the edge la, and is connected, analogously to the first embodiment described above, to a movable pin or stem 6 of an electromagnet 5, also forming part of the group G positioned inside the body C.

Elastic return spring means are also present (not illustrated) .

The pendulum element 8 comprises a lower end 9 shaped as a tooth or step 10 suitable for cooperating with a lower corner K" ' of the trolley 3.

In this way, when in use, once the preselected tightening torque has been reached, for example, preferably previously preset on a digital display present on the wrench C itself, in a known way and therefore not illustrated, the electromagnet 5 is activated to push the pendulum element 8 and rotate the same element 8 around the pin PBa so as to cause the step 10 to push the trolley 3 upwards, whose roll 2" can therefore slide along the vertical edge la, consequently causing the trolley 3 itself to be released, moving upwards, thus causing the movement of the levers L which definitively blocks the tightening action of the blocking devices.

With the invention described above, a snap torque wrench is therefore obtained, electromechanically piloted, extremely accurate, reliable and effective, and whose functionalities can be digitally programmed.