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Title:
VICE FOR RETAINING METAL BODIES AND METHOD FOR BLOCKING A METAL BODY BY MEANS OF SAID VICE
Document Type and Number:
WIPO Patent Application WO/2019/030702
Kind Code:
A1
Abstract:
Vice for retaining metal bodies which comprises: two opposite primary jaws (3), each of which provided with a first operating surface (4) susceptible of coming into contact with a metal body to be retained (O), and is actuatable closer to or further away from the opposite primary jaw (3); at least one secondary jaw (6) for each primary jaw (3), which is provided with a second operating surface (7) and is movable closer to or further away from the opposite secondary jaw (6). The first operating surface (4) of the primary jaws (3) defines a step-like seat delimited by a base surface (8), susceptible of receiving the metal body (O) in abutment, and by a lateral surface (9), susceptible of coming into contact with the metal body (O). The second operating surface (7) of the secondary jaws (6) is provided with a clamping tooth (12) adapted to come into abutment against the metal body (O).

Inventors:
CANUTO, Almerino (Via San Michele 13, Casale Sul Sile, I-31032, IT)
Application Number:
IB2018/055999
Publication Date:
February 14, 2019
Filing Date:
August 09, 2018
Export Citation:
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Assignee:
FCS SYSTEM S.R.L. (Via Belvedere 48, Casale Sul Sile, I-31032, IT)
International Classes:
B25B1/24; B25B5/16
Foreign References:
US8336867B12012-12-25
DE1402404A11968-11-28
US0381890A1888-04-24
Attorney, Agent or Firm:
GALLO, Luca (Via Rezzonico 6, Padova, I-35131, IT)
Download PDF:
Claims:
CLAIMS

1. Vice (1) for retaining metal bodies, which comprises:

- at least one support structure (2),

- at least two primary jaws (3) mechanically mounted on said support structure (2) and one placed in front of the other, each of which provided with at least one first operative surface (4) opposite the corresponding first operative surface (4) of the opposite said primary jaw (3); said first operative surface (4) being susceptible of coming into contact with at least one portion of an external surface of a metal body to be retained (O) interposed between the first operative surfaces (4) of said two primary jaws (3);

- at least one primary screw (5), which is extended along a longitudinal axis (X), is mechanically associated with said support structure (2) and with at least one of said primary jaws (3) by means of a screw-nut screw coupling and is actuatable to move, along said longitudinal axis (X), said at least one primary jaw (3) closer to or further away from said opposite primary jaw (3);

- at least one secondary jaw (6) for each of said primary jaws (3), which is mechanically associated with the corresponding said primary jaw (3) at said first operative surface (4) by means of coupling means (13) and provided with a second operative surface (7), opposite the corresponding second operative surface (7) of the opposite secondary jaw (6) associated with the opposite primary jaw (3); each said secondary jaw (6) being movable by means of said coupling means (13) closer to or further away from said opposite secondary jaw (6) along a movement direction (Y) tilted towards said support structure (2) and towards said opposite secondary jaw (6) by an angle (a) with respect to said longitudinal axis (X); said movement direction (Y) of each said secondary jaw (6) being mirrored with respect to the movement direction (Y) of the corresponding said opposite secondary jaw (6) associated with said opposite primary jaw (3);

said vice (1) being characterized in that:

- the first operative surface (4) of said primary jaws (3) defines a first step-like seat delimited by at least:

- a first base surface (8) substantially parallel to said longitudinal axis (X), which is susceptible of receiving said metal body to be retained (O) in abutment, and

- a first lateral surface (9) substantially orthogonal to said base surface (8), which is susceptible of coming into contact with said metal body to be retained (O);

- the second operative surface (7) of said secondary jaws (6) is provided with at least one clamping tooth (12) projecting substantially towards the clamping tooth (12) of said opposite secondary jaw (6) and being adapted to come into abutment against said metal body to be retained (O) in order to exert a clamping force (F2); wherein said coupling means (13) are arranged to be actuated for moving said at least one secondary jaw (6) along said movement direction (Y) so as to bring the clamping tooth (12) of said second operative surface (7) in abutment against said metal body to be retained (O) with said clamping force (F2).

2. Vice (1) for retaining metal bodies according to claim 1, characterized in that the second operative surface (7) of said secondary jaws (6) defines a second step-like seat, such second step-like seat delimited by at least:

- one second base surface (10) substantially parallel to the first base surface (8) of the first operative surface (4) of said primary jaws (3), and

- one second lateral surface (11) connected to said second base surface (10) and substantially opposite the corresponding second lateral surface (11) of said opposite secondary jaw (6).

3. Vice (1) for retaining metal bodies according to claim 1, characterized in that said coupling means (13) comprise:

- at least one guide (14) made in each said primary jaw (3) at said first operative surface (4), extended along said movement direction (Y), and housing one of said secondary jaws (6);

- at least one secondary screw (15), which is extended along said movement direction (Y), is rotatably inserted in a through hole (17) made in said secondary jaw (6) and is mechanically engaged with a nut screw (18) made in said primary jaw (3); said secondary screw (15) being actuatable in order to make said secondary jaw (6) advance within said guide (14) along said movement direction

(Y) closer to or further away from said opposite secondary jaw (6).

4. Vice (1) for retaining metal bodies according to claim 3, characterized in that said coupling means (13), comprise:

- a return spring (16) inserted within said guide (14) coaxially with said secondary screw (15) and interposed between said secondary jaw and a shoulder (19) of said guide (14), said return spring (16) being adapted to exert an elastic force in the direction of said secondary jaw (6) moving away from said opposite secondary jaw (6).

5. Vice (1) for retaining metal bodies according to any one of the preceding claims, characterized in that each said secondary jaw (6) is independent with respect to the remaining said secondary jaws (6).

6. Vice (1) for retaining metal bodies according to claim 1, characterized in that the tilt angle (a) of said movement direction (Y) is comprised between 45° and 85°.

7. Method for blocking a metal body by means of a vice (1) according to one or more of the preceding claims, and such method is characterized in that it comprises:

- a step of moving apart said secondary jaws (6), in which said coupling means (13) are actuated for moving said at least one secondary jaw (6) along said movement direction (Y) until the corresponding said clamping tooth (12) is brought not to protrude into the first step-like seat of the corresponding said primary jaw (3) and not to protrude beyond the first lateral surface (9) of said primary jaw (3);

- a positioning step, in which said primary screw (5) is actuated for positioning said primary jaws (3) at an operating distance for the insertion of said metal body to be retained (O) in the first step-like seats of the first operative surfaces (4) of said primary jaws (3);

- a clamping step, in which said coupling means (13) are actuated for positioning said at least one secondary jaw (6) along said movement direction (Y) so as to bring the clamping tooth (12) of said second operative surface (7) in abutment against said metal body to be retained (O) with said clamping force (F2).

8. Method for blocking a metal body by means of a vice (1), according to claim 7, characterized in that it comprises a retention step provided after said positioning step and before said clamping step, in which said primary screw (5) is actuated for bringing the first lateral surface (9) of the first operative surface (4) of said primary jaws (3) in abutment against said metal body to be retained (O) by exerting a retention force (Fl).

9. Method for blocking a metal body by means of a vice (1), according to claim 7, characterized in that following said positioning step and said clamping step, said metal body to be retained (O) is supported by at least one first base surface (8) of said primary jaws (3) and/or by at least one second base surface (9) of said secondary jaws (6).

10. Method for blocking a metal body by means of a vice (1), according to claim 7, characterized in that said clamping tooth (12) exerts, on said metal body to be retained (O), a clamping force (F2) susceptible of creating a mark.

11. Method for blocking a metal body by means of a vice (1), according to claim 7, wherein the coupling means (13) of said vice (1) comprise at least one guide (14) made in each said primary jaw (3) at said first operative surface (4), extended along said movement direction (Y), and housing one of said secondary jaws (6);

said method being characterized in that, in said step of moving apart said secondary jaws (6), said coupling means (13) are actuated for moving said at least one secondary jaw (6) along said movement direction (Y) until the corresponding said clamping tooth (12) is brought within said guide (14).

Description:
VICE FOR RETAINING METAL BODIES AND METHOD FOR BLOCKING A METAL BODY BY MEANS OF SAID VICE

DESCRIPTION

Field of application

The present invention regards a vice for retaining metal bodies and a method for blocking a metal body by means of said vice, according to the preamble of the respective independent claims.

The present vice is intended to be employed in the metal/mechanical industry, for retaining metal bodies during various steps of the working thereof.

More particularly, the vice, object of the present invention, is advantageously employable for blocking and retaining a metal body in a pre-established position during the working thereof.

Advantageously the vice is intended to be employed for retaining steel molds during their finishing operations, such as turning, milling, drilling etc.

The invention is therefore inserted in the scope of the industrial field of precision metal/mechanical working.

State of the art

In the scope of the field of working metal bodies such as molds through operations of turning, milling, drilling etc. there is the particular need to stably retain the same metal bodies to be worked.

For such purpose, vices are known on the market that are provided with a pair of jaws actuatable by means of a screw to be moved closer to or further away from each other, in order to block or release a metal body to be retained. One example of such vices of known type is described in the patent DE 10117116.

Such vices have in practice shown that they do not lack drawbacks.

The main drawback of these vices of known type is that of subjecting the screw to dynamic friction forces that are progressively increasing as the jaw associated with the screw is first brought in abutment against the metal body to be retained and then is made to further advance against the metal body itself, up to even creating a mark/impression on the metal body in order to more firmly block it.

The dynamic friction forces are particularly damaging for the coupling of screw-nut screw type existing between the screw and the jaws, since they can involve a quick wear of the threads, making it necessary to substitute the screw and/or the jaws with the nut screw associated therewith.

There is therefore the particular need in the reference field to avoid subjecting the primary screw to dynamic friction forces.

In order to overcome such drawback, vices have been proposed that are described in the patents US 2861494 and US 381890, which are provided with a pair of primary jaws, actuatable closer to or further away from each other by means of a primary screw, and with a pair of secondary jaws, each mounted on a corresponding primary jaw, and such secondary jaws are actuatable to be moved closer to or further away from each other by means of corresponding secondary screws.

The aforesaid vices provided with secondary jaws provide that only the latter block the metal body to be retained, while the primary jaws never come into contact with the metal body to be retained.

The vices provided with secondary jaws, of the above-described known type, have the advantage of subjecting only the secondary screws associated with the secondary jaws to the dynamic friction forces deriving from the movement of the secondary jaws against the metal body, thus preserving the primary screw from such dynamic friction forces.

Nevertheless, also such vices have in practice proven that they do not lack drawbacks. One drawback lies in the fact that the secondary jaws of such vices of known type do not have a shape that is suitable for firmly and correctly retaining the metal body for the subsequent work operations (e.g. milling) on the same metal body. In addition with such vices it is not possible to adjust the position of the metal body and hence they do not always allow an optimal positioning thereof.

So-called "lowered grip" vices (termed such in the technical jargon of the field) are also known; these are provided with a pair of jaws actuatable in order to grip only on a lower portion of the metal body. Nevertheless, such vices, able to act only on a limited surface of the metal body, must exert very high clamping forces which involve corresponding high dynamic friction forces and, therefore, a quick wear and/or damage of the vice itself.

A further drawback of the vices of known type considered up to know lies in the fact that the jaws that come into contact with the metal body to be retained are unable to be perfectly adapted to possible irregular surfaces of the latter and, therefore, they do not ensure a secure grip of the metal body itself.

The patent application WO 2015/036981 describes a blocking device for bending presses, which is adapted to retain an instrument for bending metal sheets and is provided with a safety hook provided with a tooth for maintaining the tool suspended when the blocking device is loosened. The configuration described in the latter prior art document is not suitable for resolving the aforesaid problems of the abovementioned vices.

Presentation of the invention

In this situation, the problem underlying the present invention is therefore that of overcoming the drawbacks manifested by the vices of known type, by providing a vice for retaining metal bodies capable of ensuring a secure grip of the metal body itself without exerting friction forces on its components susceptible of producing undesired wear.

A further object of the present invention is to provide a vice which is capable of ensuring a secure grip of the metal body yet without obstructing the working thereof by external machinery, such as machines for milling, drilling or still other working.

A further object of the present invention is to provide a vice which is also capable of being adapted to bodies provided with non-flat surfaces.

A further object of the present invention is to provide a vice that is safe and reliable during use.

A further object of the present invention is to provide a vice that is simple to use.

Brief description of the drawings

The technical characteristics of the invention, according to the aforesaid objects, can be clearly seen in the contents of the below-reported claims and the advantages thereof will be more evident in the following detailed description, made with reference to the enclosed drawings, which represent merely exemplifying and non-limiting embodiments of the invention, in which:

- Figure 1 shows an overall perspective view of the vice for retaining metal bodies, object of the present invention;

- Figure 2 shows a plan view of the vice of figure 1, with - interposed between the jaws - a metal body to be retained and provided with non-flat surfaces; - Figure 3 shows a side view of the vice of figure 1, with the primary jaws indicated closer to a metal body;

- Figure 4 shows a detail of the vice of figure 3 relative to two secondary jaws with the metal body interposed;

- Figure 5 shows a longitudinal section view of the vice of figure 1, made along the trace III-III of figure 2, the metal body having been omitted;

- Figure 6 shows a second embodiment of the vice, object of the present invention, illustrated in a longitudinal section view;

- Figure 7 shows a third embodiment of the vice, object of the present invention, in a side view partly illustrated in longitudinal section view.

Detailed description of a preferred embodiment

With reference to the enclosed drawings, reference number 1 overall indicates a vice for retaining metal bodies, according to the present invention.

It is intended for being employed for retaining metal bodies in a pre-established position advantageously during the possible steps of working the metal body itself, such as turning, milling, drilling steps or still other steps.

In accordance with the embodiments of the enclosed figures, the vice 1 comprises at least one support structure 2 and at least two primary jaws 3, mechanically mounted on the support structure 2 and one placed in front of the other.

Advantageously, the support structure 2 of the vice 1 is intended to be fixed in a suitable position on a work surface 33, by means of clamping means 34 of known type.

Each primary jaw 3 is provided with at least one first operating surface 4 opposite the corresponding first operating surface 4 of the opposite primary jaw 3.

Each first operating surface 4 is susceptible of coming into contact with at least one portion of an external surface of a metal body to be retained O, which is interposed between the first operative surfaces 4 of the two primary jaws 3.

The vice 1 also comprises at least one primary screw 5, which is extended along a longitudinal axis X placed to join the two primary jaws 3 and preferably horizontal. The aforesaid primary screw 5 is mechanically associated with the support structure 2 and with at least one of the two primary jaws 3, by means of a first screw-nut screw coupling, and is actuatable for moving, along the longitudinal axis X, the primary jaw 3 associated therewith closer to or further away from the opposite primary jaw 3. The vice 1, object of the present invention, also comprises at least one secondary jaw 6 for each primary jaw 3 and preferably comprises two secondary jaws 6 for each primary jaw 3.

Each secondary jaw 6 is mechanically associated with the corresponding primary jaw 3 at the first operating surface 4 by means of coupling means 13 and is provided with a second operating surface 7, opposite the corresponding second operating surface 7 of the opposite secondary jaw 6 associated with the opposite primary jaw 3.

Each secondary jaw 6 is movable by means of the coupling means 13 closer to or further away from the opposite secondary jaw 6 along a movement direction Y tilted towards the support structure 2 and towards the opposite secondary jaw 6 by an angle a with respect to the longitudinal axis X.

Advantageously, the tilt angle a of the movement direction Y with respect to the longitudinal axis X is comprised between 45° and 85° and preferably is comprised between 60° and 80° and is preferably about 75°.

In addition, the movement direction Y of each secondary jaw 6 is mirrored with respect to the movement direction Y of the corresponding opposite secondary jaw 6 associated with the opposite primary jaw 3.

In operation, in accordance with the preferred embodiment illustrated in figure 4, the movement of each secondary jaw 6 closer to the opposite secondary jaw 6 also involves a movement of the same secondary jaw 6 towards the support structure 2, i.e. downward.

According to the idea underlying the present invention, the first operating surface 4 of the primary jaws 3 defines a first step-like seat delimited by at least one first base surface 8, which is substantially parallel to the longitudinal axis X and is susceptible of receiving in abutment the metal body to be retained O; and by at least one first lateral surface 9 substantially orthogonal to the base surface 8 and susceptible of coming into contact with the metal body to be retained O.

Advantageously, the primary jaw 3 can be moved, by means of the approaching actuation of the primary screw 5, up to abutting against the metal body to be retained O and exerting a retention force F 1.

In addition, according to the idea underlying the present invention, the second operating surface 7 of the secondary jaws 6 is provided with at least one clamping tooth 12 projecting substantially towards the clamping tooth 12 of the opposite secondary jaw 6 and is adapted to come into abutment against the metal body to be retained O in order to exert a clamping force F2.

Advantageously, the vice according to the invention, as also described more in detail hereinbelow, allows the retention force Fl exerted by the primary jaws on the metal body to be small, or even zero if the first lateral surface 9 of the primary jaw 3 is not in contact with the metal body to be retained O, for example due to an irregularity of the metal body to be retained O, while the clamping force F2 exerted by the secondary jaws 6 is high. Preferably, moreover, the retention force Fl exerted by the primary jaws 3 has a lower intensity than the clamping force F2 exerted by the secondary jaws 6.

In accordance with the preferred embodiment illustrated in all of the enclosed figures, the vice 1 is provided with two secondary jaws 6 for each primary jaw 3, and such secondary jaws 6 are side-by-side and centrally arranged along the first operating surface 4 of the corresponding primary jaw 3.

In addition, each secondary jaw 6 is advantageously separate and independent with respect to the remaining secondary jaws 6. More in detail, with the term "independent" it is intended that the secondary jaws 6 are mechanically uncoupled from each other and the actuation of one of these does not involve the actuation of the others.

Consequently, the vice 1 is overall provided with four independent secondary jaws 6, which are capable of gripping at four separate and independent points of the metal body to be retained O, ensuring a secure grip even of bodies provided with non-flat surfaces, as illustrated in figure 2.

In accordance with the preferred embodiment, each second operating surface 7 of the secondary jaws 6 defines a second step-like seat, delimited by at least one second base surface 10 and by a second lateral surface 11.

More in detail, the second base surface 10 is substantially parallel to the first base surface 8 of the first operating surface 4 of the primary jaws 3 while the second lateral surface 11 is connected to the second base surface 10 and substantially opposite the corresponding second lateral surface 11 of the opposite secondary jaw 6.

In accordance with the preferred embodiment described up to now, the vice 1 is capable of blocking the metal body to be retained O by means of the primary jaws 3 and/or of the secondary jaws 6. In particular, the metal body to be retained O can lie on the first base surface 8 of a primary jaw 3 and/or on the second base surface 10 of a secondary jaw 6. In the same manner, the metal body to be retained O can be blocked by the first lateral surface 9 of a primary jaw 3 and/or by the clamping tooth 12 of a secondary jaw 6. The multiple abutment and blocking possibilities offered by the two types of jaws, primary and secondary, allow attaining a vast array of adjustments of the blocking position of the metal body to be retained O, for example necessary in the case of irregularity of the body itself.

As described more in detail hereinbelow, in operation in order to block a metal body by means of the vice 1 object of the present invention, provision is made for inserting the metal body to be retained O within the first step-like seats of the two opposite primary jaws 3, preferably in abutment against the first base surfaces 8, and subsequently for separately actuating at least one secondary jaw 6 for bringing the corresponding clamping tooth 12 in abutment against the metal body to be retained O. As already mentioned above, the actuation of one of the secondary jaws 6 closer to the corresponding opposite secondary jaw 6 also involves a movement downward thereof and, hence, the movement of its second base surface 10 downward, even up to positioning the latter below the first base surface 8 of the primary jaw 3. In this case, the metal body to be retained O will only be situated in abutment against the first base surface 8 of the primary jaw 3.

However, the actuation of one of the secondary jaws 6 further away from the corresponding opposite secondary jaw 6 also involves an upward movement thereof and, hence the movement of its second base surface 10 upward, even up to positioning the latter above the first base surface 8 of the primary jaw 3. In this case, the metal body to be retained O will be situated in abutment against the second base surface 10 of the secondary jaw 6.

Since the secondary jaws 6 are independent from each other, it is possible that a same metal body to be retained O is simultaneously in abutment, on one side, against the first base surface 8 of a primary jaw 3 and on the other side against the second base surface 10 of the secondary jaw 6 associated with the opposite primary jaw 3. In other words, in accordance with the preferred embodiment in which each primary jaw 3 is associated with two secondary jaws 6, it is also possible that the metal body to be retained O is simultaneously in abutment against none, one or more of the second base surfaces 10 of the secondary jaws 6 and against one or both first base surfaces 8 of the primary jaws 3, depending on the position in which the secondary jaws 6 are moved and depending on the shape of the metal body to be retained O.

Analogously, the actuation of one of the secondary jaws 6 closer to or further away from the corresponding opposite secondary jaw 6 can or cannot lead the clamping tooth 12 to protrude within the first step-like seat, beyond the first lateral surface 9 of the corresponding primary jaw 3. In the first case, therefore, it will be the clamping tooth 12 of the secondary jaw 6 to abut against the metal body to be retained O, in the second case it will be the first lateral surface 9 of the primary jaw 3 to abut against the metal body to be retained O.

It is therefore clear that by independently moving each secondary jaw 6, it is possible not only to block the metal object to be retained O, but also to carry out an adjustment of the position thereof, for example in order to compensate for irregularities of its surfaces.

Advantageously, also the first and the second base surface 8, 10 of the primary and secondary jaws 3, 6 perform the function of retaining the metal body in a pre- established position, being susceptible of receiving in abutment the metal body to be retained O.

In accordance with the preferred embodiment illustrated in the enclosed figures, each secondary jaw 6 is provided with a lower base 21, directed towards the support structure 2 and with an upper base 22, substantially parallel and directed in the direction opposite the lower base 21. The second step-like seat of the secondary jaws 6 is made at a section of the corner defined between the upper base 22 and the lateral face of the secondary jaw 6 directed towards the opposite secondary jaw 6.

Advantageously, moreover, the means 13 for coupling each secondary jaw 6 to the corresponding primary jaw 3 comprise at least one guide 14 made in each primary jaw 3 at the first operating surface 4, and such guide 14 is extended along the movement direction Y and houses one of the secondary jaws 6.

More in detail, the guide 14 is a cavity made in the primary jaw 3 starting from an upper surface 23 thereof. The guide 14 is then provided with an upper opening made at the upper surface 23 of the primary jaw 3. The guide 14 is also provided with a front opening directed towards the opposite primary jaw 3 and made at the first operating surface 4 in order to allow the clamping tooth 12 of the secondary jaws 6 to protrude inside the first step-like seat of the primary jaws 3, i.e. beyond the first lateral surface 9 when the secondary jaw 6 is moved closer to the opposite secondary jaw 6.

Still more in detail, the guide 14 is provided with a bottom surface 26 susceptible of receiving the lower base 21 of the secondary jaw 6 in abutment when this is at the end stop in the same guide 14, or completely moved in the direction approaching towards the opposite secondary jaw 6.

The coupling means 13 also comprise at least one secondary screw 15, which is extended along the movement direction Y, is rotatably inserted in a through hole 17 made in the secondary jaw 6 and is mechanically engaged with a nut screw 18 made in the primary jaw 3. The aforesaid secondary screw 15 is actuatable in order to make the secondary jaw 6 advance within the guide 14, along the movement direction Y, closer to or further away from the opposite secondary jaw 6.

Advantageously, the coupling means 13 also comprise a return spring 16 inserted within the guide 14 coaxially with the secondary screw 15 and interposed between the secondary jaw 6 and a shoulder 19 of the guide 14. More in detail, the return spring 16 is inserted between the lower base 21 of the secondary jaw 6 and the shoulder 19 of the guide 14, made at the bottom surface 26 of the guide 14.

Advantageously, the return spring 16 is susceptible of exerting an elastic force directed in the direction of the secondary jaw 6 moving away from the opposite secondary jaw 6, i.e. from the bottom surface 26 of the guide 14. In other words and more clearly, the elastic force exerted by the spring 16 is opposed to the screwing of the secondary screw 15 and forces the secondary jaw 6 along the movement direction Y towards the guide 14 exterior, i.e. towards its upper opening.

More in detail, when the secondary screw 15 is screwed in the nut screw 18, the head of the secondary screw 15 pushes the secondary jaw 6 closer to the opposite secondary jaw 6 and, simultaneously, towards the bottom surface 26 of the guide 14, compressing the return spring 16. When, however, the secondary screw 15 is loosened in the nut screw 18, the secondary jaw 6 is pushed by the elastic force exerted by the return spring 16 further away from the bottom surface 26 of the guide 14 and, thus, further away from the opposite secondary jaw 6.

In accordance with a first embodiment of the present invention, illustrated in figures 1, 3 and 5, the primary screw 5 of the vice 1 is associated with both primary jaws 3 and is actuatable for simultaneously moving the two primary jaws 3 in a mirrored manner with respect to a substantially median section thereof. The vice 1 thus obtained is of self- centering type.

More in detail, the primary screw 5 of the self-centering vice 1 is extended along the longitudinal axis X between a first and a second end 31, 32. The primary screw 5 is also provided with a first and a second thread, and such first thread is extended starting from the first end 31 up to a section of the primary screw 5 that is substantially median with respect to its extension thereof along the longitudinal axis X, and the second thread is extended starting from the second end 32 up to the median section of the primary screw

5. Advantageously, the first and the second thread are helically wound around the primary screw 5 with opposite rotation senses and each engages one of the two primary jaws 3.

Also provided for is a central support bushing 30, fixed to the support body 2 for example by means of a screw and traversed by said primary screw 5. The support bushing 30 engages the primary screw 5 in its median portion such that it does not translate along the longitudinal axis X thereof, while allowing the free rotation thereof around the same axis X.

In operation, by actuating the primary screw 5 to rotate, the two primary jaws 3 are simultaneously moved, closer to or further away from each other, by an equal distance with respect to the rotation fulcrum 30.

In accordance with a second embodiment of the present invention, illustrated in figure

6, the vice 1 comprises a first primary screw 5', mechanically associated with one of the two primary jaws 3, and a second primary screw 5", mechanically associated with the opposite primary jaw 3; each of such primary screws 5', 5" is actuatable for moving the primary jaw 3 associated therewith independently from the opposite primary jaw 3. The vice 1 thus obtained is of the type termed modular.

Advantageously, the above-described modular vice 1 comprises two support structures 2, one for each primary screw-primary jaw 5 '-3, 5 "-3 coupling, and such support structures 2 are mechanically associable with the work surface 33 by means of the clamping means 34 of known type. More in detail, the two support structures 2 of the modular vice 1 are clamped to the work surface 33 in front of each other, arranged along the longitudinal axis X with the two first operative surfaces 4 of the primary jaws 3 opposite each other.

The above-described modular vice 1 is advantageously employable when the distance that separates the two primary jaws 3 is a very high distance, such that a single primary screw 5 would be subjected to overly high bending stresses.

In accordance with a third embodiment of the present invention, illustrated in figure 7, the vice 1 comprises a double primary jaw 3', i.e. provided with two first operative surfaces 4, opposite each other, which define two first step-like seats opposite each other. The vice 1 thus obtained is of the type termed multi-piece.

Advantageously, the double primary jaw 3' of the multi -piece vice 1 described above is interposed between another two external primary jaws 3", 3" ', e.g. of the type described above in the second embodiment, in order to simultaneously retain two metal bodies O. Advantageously, moreover, the double primary jaw 3' is fixed, i.e. it is not mechanically associated with a primary screw 5; indeed, it remains substantially fixed at the center of the vice 1, while the two external primary jaws 3", 3" ' are actuated for blocking the two metal bodies to be retained O.

The double primary jaw 3' is provided with at least one secondary jaw 6 for each first operating surface 4 thereof, i.e. it is advantageously provided with at least two secondary jaws 6, which are movable along two movement directions Y that are opposite and mirrored with respect to each other, each tilted towards the corresponding secondary jaw 6 associated with the opposite external primary jaw 3', 3" .

Also forming the object of the present invention is a method for blocking a metal body by means of the vice 1 of the above-described type.

Hereinbelow, for simplicity of description, reference will be made to the same nomenclature introduced up to now, even if it must be intended that the present method can also be obtained with devices not provided with all of the above-considered characteristics.

The method, object of the present invention, provides for a step of moving apart the secondary jaws 6, wherein the coupling means 13 are actuated for moving at least one secondary jaw 6 along the movement direction Y until the corresponding clamping tooth 12 is brought such that it does not protrude into the first step-like seat of the corresponding primary jaw 3 and such that it does not protrude beyond the first lateral surface 9 of the first step-like seat of such primary jaw 3.

Advantageously, in the aforesaid step of moving apart the secondary jaws 6, the coupling means 13 are actuated for moving at least one secondary jaw 6 along the movement direction Y until the corresponding clamping tooth 12 is brought within the guide 14. More in detail, the secondary screw 15 associated with the secondary jaw 6 is loosened and the corresponding return spring 16 pushes the secondary jaw 6 further away from the opposite secondary jaw 6, until the clamping tooth 12 is brought such to not protrude into the first step-like seat of the primary jaw 3; in other words, the clamping tooth 12 does not project beyond the first lateral surface 9 of the primary jaw 3.

Subsequently, a positioning step is provided for, in which the primary screw 5 is actuated for positioning the primary jaws 3 at an operating distance for the insertion of the metal body to be retained O in the first step-like seats of the first operative surfaces 4 of the primary jaws 3, for example in abutment against the first base surface 8 of the primary jaws 3.

Preferably, in the moving-apart step, the second base surface 11 of the secondary jaws 6 is maintained within the guide 14, i.e. below the first base surface 8 of the corresponding primary jaw 3. Then, in the positioning step, the metal body to be retained O is preferably in abutment against the first base surface 8 of the primary jaws 3.

The method for blocking a metal body by means of the vice 1 also provides for a clamping step, in which the coupling means 13 are actuated for moving at least one secondary jaw 6 along the movement direction Y, bringing the clamping tooth 12 of the secondary jaws 6 in abutment against the metal body to be retained O by exerting the clamping force F2.

Advantageously, following the positioning step and the clamping step, the metal body to be retained O is supported by at least one first base surface 8 of the primary jaws 3 and/or by at least one second base surface 10 of the secondary jaws 6, in relation to the position of the secondary jaws 6 and of the surface of the metal body itself. In addition, the metal body to be retained O is blocked by at least one clamping tooth 12 of the secondary jaws 6 and/or by at least one first lateral surface 9 of the primary jaws 3. Advantageously, the method for blocking metal bodies by means of the vice 1 comprises a retention step, provided for after the positioning step and before the clamping step, in which the primary screw 5 is actuated for bringing the lateral surface 9 of the first operating surface 4 of the primary jaws 3 in abutment against the metal body to be retained O by exerting the retention force Fl on the metal body itself.

Preferably, the above-described method for blocking a metal body provides that the retention force Fl exerted by the primary jaw 3 has a lower intensity than the clamping force F2 exerted by the secondary jaw 6. This because a retention force Fl of small intensity allows not imparting high dynamic friction forces on the primary screw 5 which moves the primary jaw 3 in abutment against the metal body to be retained, allowing the preservation of the screw-nut screw coupling which associates the primary screw 5 with the primary jaw 3.

In addition, preferably, the clamping tooth 12 is moved in abutment against the metal body to be retained O with a high-intensity clamping force F2, in order to ensure a correct blocking of the metal body to be retained O and advantageously the clamping force F2 is susceptible of creating a mark/impression on the body itself, in order to ensure the blocking thereof.