EP2265411A1

EP2265411A1 - Gripping and screwing bit intended to equip a screwing device

Info

Publication number: EP2265411A1
Application number: EP09728518A
Authority: EP
Inventors: Alain Leroy
Original assignee: Ateliers LR Etanco SAS
Current assignee: Ateliers LR Etanco SAS
Priority date: 2008-03-13
Filing date: 2009-02-26
Publication date: 2010-12-29
Anticipated expiration: 2029-02-26
Also published as: ATE514529T1; EP2265411B1; WO2009122025A1; FR2928574A1; FR2928574B1; ES2369067T3; PL2265411T3

Abstract

The gripping and screwing bit according to the invention comprises a sleeve (10), a gripping mechanism (14) which can move inside said sleeve (10), this mechanism comprising two jaws (15, 16) which can move translationally with respect to one another in a radial plane, conversion means designed to translate the two jaws (15, 16) radially following an axial movement of the gripping mechanism (14) so as to change from an open position, in which the two jaws (15, 16) are separated from one another and extend outside the sleeve (10), to a closed position in which the two jaws (15, 16) are retracted and are returned inside the sleeve (10). Structures formed at the end of the jaws (15, 16) allow the head (1) of the screw to be gripped by its peripheral edge, with said head (1) and said jaws (15, 16) being secured against relative rotation, by means of shape complementarity.

Description

PRETENSION AND SCREWING BIT FOR EQUIPPING A SCREWDRIVER.

The present invention relates to a gripping and screwing end for fitting a screwing device such as, for example, a motorized screwdriver / unscrewer.

It applies in particular, but not exclusively, to screws whose head has at its periphery conformations intended to cooperate with a screwing tool, on the one hand, to ensure an axial connection between the tool and the screw and, on the other hand, to allow the tool to exert on the screw a screwing torque.

By the patent application EP No. 03 291 794.0, the Applicant has already proposed a screw socket having, at one of its ends, a coaxial cavity opening to the outside, so as to receive the head of the opinion. The inner surface of the bushing which delimits this cavity, has conformations capable of coming into engagement with that of the head of the screw, so as to ensure the transmission of the tightening torque. This tip is provided with gripping means which engage in a space provided under the head of the screw during the introduction of the head of the screw inside the tip.

This solution has the advantage of separating the rotational drive function from the gripping function. As a result, the gripping means, which no longer have a rotational drive function, may have reduced dimensions. The effectiveness of the screwing remains guaranteed by the fact that the screwing bush behaves like a conventional socket wrench of indeformable section.

However, this solution has a drawback due to the fact that, given the indeformability of the sleeve, it is only suitable for screws whose heads have a relatively high accuracy.

If the outer section of the head does not exactly correspond to the inner section of the socket, we observe:

- it is impossible to engage the head in the socket,

- Or a game between the head and the bushing, this game proving harmful because it leads to a ball head effect inside the bushing.

It is clear that a reinforcement of the gripping means to reduce this effect of kneecap would be counter to the goal sought in this solution, which aims on the contrary to take advantage of the separation of the gripping and driving functions to reduce the dimensions gripping means.

However, it turns out that high-speed production techniques do not always make it possible to guarantee sufficient precision of the screw heads to avoid the disadvantages mentioned above. This is particularly the case when, at the end of the manufacturing cycle, the screw heads undergo a surface treatment resulting in a deposit of material of poorly controlled thickness (deposition of metal, metal oxide, paint, etc. .).

In addition, the previously described solution provides a cooperation of a conformation of the jaws with an appropriate conformation of the sleeve to cause a tilting of the jaws around articulation means, when the jaws move from a forward end position where they are open to a rear end position in which the jaws are retracted into the socket in the closed position. In fact, these conformations involve ramps that extend obliquely with respect to the longitudinal axis of the bushing.

The presence of these ramps and tilting of the jaws imply the presence of a large annular space between the sleeve and the jaws and therefore an increase in the diameter of the sleeve.

This increase in volume is amplified because of the presence, inside the sleeve, of a coaxial central core for ensuring the axial sliding of the jaws (the presence of the ramps prevents this sliding can be ensured by the outer surface of the socket).

The object of the invention is therefore more particularly to eliminate these disadvantages.

For this purpose, it proposes a gripping and screwing tip comprising:

a sleeve having, on one side, means for driving in rotation and, on the other side, a coaxial cavity opening outwards through a circular orifice,

- A gripping mechanism movable axially inside said cavity, this mechanism comprising two jaws movable in translation, with respect to one another, in a radial plane,

- Conversion means adapted to control the radial translation of the two jaws following an axial displacement of the gripping mechanism, so as to pass from an open position, in which the two jaws are spaced one of the other and stand outside the socket, at a closed position in which the two jaws are retracted and retracted into the socket,

conformations provided at the ends of the jaws to allow engagement of the head of the screw, in the separated position of the jaws, then gripping said head by its peripheral edge with rotationally fastening of said head and said jaws, by complementarity of shapes, when said jaws are in the retracted position, retracted inside said sleeve.

Advantageously, the two jaws may have an elongated body terminated, on one side, by a circular collar portion having the aforesaid conformations.

One of the two jaws, female type, may include a cylindrical body with an axial cavity of rectangular section.

The other jaw, of male type, may then comprise a body of parallelepipedal shape of section substantially complementary to that of the axial cavity in which it engages and can slide radially. This body also has a circular flange fraction which extends in line with that of the female-type jaw when the two jaws are in the retracted position.

The aforementioned conversion means may in turn involve:

on the one hand, two axially offset parallel radial pins passing through the cavity of the socket and engaging respectively in two pairs of coaxial bores provided in the socket, - On the other hand, at least two oblong holes radially through, respectively provided in each jaw, these oblong holes being arranged to be two by two in coincidence and to define two radial passages through which engage respectively the two pins.

Each of these oblong holes comprises an axial portion followed by an oblique portion, the oblique portions of two oblong holes in coincidence (through which the same pin passes) being oriented opposite to each other.

Furthermore, the two jaws may also comprise at least two coaxial radial bores oriented perpendicular to said pins and in which engages a guide axis allowing a radial displacement in translation of the two jaws.

A spring may also be provided, coaxially with this axis to generate on the two jaws a force tending to separate them from one another.

Advantageously, the outer diameter of the collar portions of the jaws may be equal to the inside diameter of the sleeve so that in the retracted position of the jaws, the flange portions are at least partially tightly engaged in the sleeve.

Embodiments of the invention will be described below, by way of non-limiting examples, with reference to the accompanying drawings in which:

Figures 1 and 2 are two views in elevation, 90 ° to one another, a gripping and screwing tip according to the invention wherein the jaws are in the deployed position;

Figure 3 is a section along AA 'of Figure 2; Figures 4 to 6 are views similar to those of Figures 1 to 3, but wherein the jaws are in the retracted position;

Figure 7 is a perspective view of a female jaw;

Figure 8 is a side view of the jaw shown in Figure 7;

Figure 9 is an end view on the flange side of the female jaw;

Figures 10 to 12 show a male jaw respectively in perspective (Figure 10), in elevation (Figure 11) and side end view flange (Figure 12);

FIGS. 13 and 14 are views respectively in elevation (FIG. 13) and in axial section along BB 'of FIG. 13 (FIG. 14) of an alternative embodiment of a gripping and screwing bit according to the invention .

Figures 15 and 16 show in perspective (Figure 15) and in end view (Figure 16) a male-type jaw of the nozzle shown in Figures 13 and 14;

Figures 17 and 18 show in perspective (Figure 17) and in end view (Figure 18) a female-type jaw of the nozzle shown in Figures 13 and 14;

Fig. 19 is a schematic representation showing the position of the polygonal section of the screw head in the fingerprints of the jaw of the tip shown in Figs. 13-18. In the example shown in FIGS. 1 to 12, the gripping and screwing tip is intended for screws comprising a head 1, having a convex upper face 2 comprising in the center an injection bowl. The presence of this bowl exists only in the case where the head is overmolded. By cons, in the case of a cold forging (rolling), the upper face of the head 1 will be continuously curved. The peripheral edge 3 of the head 1 is serrated and here comprises fifteen teeth separated by notches forming an angle of about 120 °.

This head 1 is connected to a coaxial rod 7 via a cylindrical portion under head 8 whose diameter is substantially equal to the distance between the bottom of the notches and the axis XX 'of the screw.

In this example, the height of the cylindrical portion 8 is substantially equal to the height of the peripheral edge 3 of the head 1. The diameter of the rod 7 of the screw at its connection to the cylindrical portion 8 is much smaller than that of the head 1 (about 50%), the connection between the cylindrical portion 8 with the peripheral edge 3 of the head 1 and with the end of the rod 7 being effected by means of radial shoulders.

In this example, the rod 7 of the screw has a self-tapping thread 4 terminated by a self-piercing tip 5.

Of course, the invention is not limited to a particular type of net or tip.

This screw can be screwed using a hand tool having a tubular nozzle whose inner profile corresponds to the outer serrated shape of the head 1. Nevertheless, it is particularly suitable for the screwdriver tip illustrated in Figures 1 to 12 which essentially comprises a tubular sleeve 10 closed on one side by a circular base 11 secured to a coaxial rod 12 partially hexagonal section, intended to engage in the mandrel of a screwdriver.

This socket 10 delimits a coaxial cylindrical cavity 13 opening outwardly opposite the bottom 11. The cylindrical wall of this cavity 13 is smooth and does not include any projecting element such as for example, a ramp.

Inside this sleeve 10 is disposed an axially movable gripping mechanism 14 which comprises two jaws 15, 16 one of which is of the male type, while the other 16 is of the female type.

The male-type jaw 15 has an axially elongated parallelepipedal body 17 comprising a cylindrical lateral side 18.

This body 17 is extended, at one of its ends, by a flange fraction 19 which extends coaxially with the lateral side 18 projecting relative thereto and which has an outside diameter substantially equal to the inside diameter of the sleeve 10.

The inner surface of this flange fraction 19 comprises successively, starting from the body 17, in the axial direction:

a toothed portion 20 in the shape of a crown sector, this serrated portion being substantially complementary to the serrated peripheral edge of the head 1 of the screw, and

- A smooth cylindrical portion of smaller diameter than that of the toothed portion 20 and preferably equal to the diameter of the cylindrical portion 7 under the head of the screw. The face of the body 17 adjacent to the collar 19 has a step 22 forming a recess with a circular profile.

The female-type jaw 16 (FIGS. 7 to 9) comprises a substantially cylindrical body 23 of the same length as the body 17 of the male-type jaw 15.

This body 23 is provided with a parallelepipedal axial cavity 24 substantially complementary to the body 17 of the jaw 15 of the male type which is intended to be housed therein.

The body 23 is extended, on one side by a flare 25 in the form of fillet, itself axially extended over a part of its periphery by a flange fraction 26 similar to that of the jaw 15 of the male type and comprising a analogously a toothed portion 20 'and a cylindrical smooth portion 21'. This flange fraction 26 is centered opposite the axial opening of the cavity 24 so that when the body 17 of the male-type jaw 15 is engaged in the cavity 24 of the body 23 of the jaw 16 of the female type, the two flange fractions 19, 26 face each other and are inscribed in the same outer circle.

The internal volume of the bushing 10 is traversed by two axially offset radial pins 30, 31, the ends of which engage in corresponding bores provided in the bushing 10.

These two pins are intended to pass through oblong through holes 32, 33 - 34, 35 - 34 ', 35' made in the body of the jaws 15, 16 of the male and female type.

For this purpose, the male-type jaw 15 comprises two oblong through-holes 32, 33 made between the two main faces of the body 17. On the other hand, the jaw 16 of the female type comprises two pairs of coaxial oblong holes 34, 34 '- 35, 35' radially through which open into the two opposite faces of the axial cavity 24.

These two pairs of oblong holes 34, 34 '- 35, 35' are arranged so that, when the body 17 of the male-type jaw 15 is engaged in the axial cavity 24 of the body 23 of the jaw 16 of the female type, the oblong coaxial bores of each pair 34, 34 '- 35, 35' are locally aligned with an oblong bore 32, 33 of the body 17 of the male jaw 15 delimiting a passage in which engages one of said pins 30, 31.

The oblong holes 32 to 35 and 34 ', 35' each comprise a portion P ₁ which extends axially and a portion P ₂ which extends obliquely with respect to the longitudinal axis of the sleeve 10.

The oblique portions P ₂ oblong holes of the same jaw extend parallel to each other.

On the other hand, the oblique portions P ₂ of the oblong holes 32, 33 of the jaw 15 of the male type are oriented opposite the oblique portions P ₂ of the oblong holes 34, 35 - 34 ', 35' of the jaw 16 of the female type.

Furthermore, the bodies 17, 23 of the jaws 15, 16 of the male and female type have two radial through holes 40, 41 oriented perpendicularly to the pins and in which an axis is engaged for axially securing the two jaws 15, 16 while allowing their radial translation.

A spring 42 disposed coaxially with the axis then exerts on the jaws a force tending to open them. With these arrangements, axial displacement of the male and female jaws 16 from the deployed position of the jaws (Figures 4 to 6) to their retracted position within the sleeve 10 (Figures 1 to 3) will allow to obtain successively:

a progressive retraction of the two jaws caused by the action of the two pins 30, 31 on the oblique portions P ₂ of the oblong holes 32 to 35 - 34 ', 35'; this retraction is effected by a double axial and radial translation without there being any rotation or tilting (the geometry of the device does not allow it);

- Once the two jaws 15, 16 are fully engaged one in the other, the flange is still outside the cavity of the sleeve, an axial translation of the jaws 15, 16 until the flange fractions 19, 26 are at least partially engaged in the cavity of the sleeve 10; in this position, the flange fractions 19, 26 are radially locked by the sleeve 10.

Thanks to these arrangements, from the arrangement of the tip illustrated in Figures 4 to 6, provision in which the jaws 15, 16 are in the deployed state and the flange portions 19, 26 stand out from the outside. the sleeve 10, the head 1 of the screw is engaged between the flange fractions 19, 26 and then exerts an axial thrust on the screw.

This thrust causes a translational movement of the jaws 15, 16 which pass to the retracted state, while the flange fractions 19, 26 encircle the edge of the head 1 of the screw in two diametrically opposite zones. At the same time, the teeth of the flange fractions 19, 26 engage between the teeth of the head 1 of the screw, ensuring rotationally fastening by complementarity of shape. At the end of axial translation, the collar portions 19, 26 engage tightly within the sleeve 10 and are therefore radially locked.

The operator can then proceed to screw the screw. At the end of screwing, the operator exerts an axial traction on the tip, which causes a displacement of the jaws 15, 16 in opposite direction and their passage in the deployed position with disengagement of the head 1 of the screw.

This solution is particularly effective and allows for gripping tips with a high compactness.

In addition, in the locked position, the pins cooperate only with the axial portions of the oblong holes, so that a process of inadvertent deployment of the jaws (due to the reversibility of a ramp assembly) can not occur.

Furthermore, the transmission of the torque between the sleeve 10 and the jaws 15, 16, which is provided by the two pins (30,31), is carried out under optimum conditions.

FIGS. 13 to 19 illustrate a variant of the gripping and screwing bit according to the invention that can be used for screws 50, the head 51 of which has a cap 52 possibly curved, terminated by a conical crown and, under this cap, a portion under head 53 of polygonal section, preferably six or eight sides, which extends coaxially with the screw.

In this example, the elements of the nozzle 54 are strictly identical to those of the nozzle described above, with the exception of the collar portions 55, 56 which, in this case, extend over nearly 180 ° (approximately 170 °) and which each comprise, successively, from the body 57, 58 of the jaws: an annular cavity 59 (FIG. 17) which extends over a fraction of circumference with a diameter substantially equal to the diameter of the cap 52 of the head 51 of the screw 50; this annular cavity may comprise a conical shape substantially complementary to the conical crown of the cap 52 of the head 51 of the screw 50, and

an imprint 60 comprising two facets 61, 62 extending at 90 ° from each other and arranged symmetrically with respect to a bisecting plane passing through the axis of the endpiece, this bisecting plane constituting a plane of symmetry also for the annular cavity 59.

The operation of this socket is similar to that of the sleeve described above.

Thus, from the extended position illustrated in FIG. 14, the head 51 of the screw 50 is engaged between the collar portions 55, 56 of the jaws, and then an axial pressure is exerted on the latter. This pressure causes a displacement in translation of the jaws inwardly of the sleeve 63 of the nozzle with passage in the retracted position. At the end of this passage in the retracted position, the two facets 61, 62 of each recess 60 are applied to a pair of corresponding flaps of the under-head portion 53 of the screw 50, thus performing a self-centering of the head 51. of the screw 50 relative to the socket.

Once in the retracted position, the flange fractions 55, 56 engage at least partially inside the sleeve 62 and are then locked radially.

The advantage of this solution (as in the previous one) is that it allows slight dimensional variations of the screw heads without affecting the proper operation of the socket. Indeed, according to these dimensional variations, the head 51 of the screw 50 will engage more or less deeply in the cavities 60 and the annular cavity 59 of the jaws, while being properly centered. Of course, it will be necessary for this purpose to provide a slight clearance between the outer surface of the collar portions 55, 56 and the inner surface of the sleeve 63.

This slight clearance will have no effect on the operation of the tip since, during the rotation of the tip, the resistant torque exerted by the screw will cause the collet fractions of the jaws, a force tending to apply firmly on the inner surface of the socket thus ensuring an automatic adjustment of play.

Claims

claims

1. End of gripping and screwing a screw whose head (1) has at its periphery conformations intended to cooperate with a screwing tool, on the one hand, to ensure an axial connection between the tool and the screw and, on the other hand, to allow the tool to exert on the screw a tightening torque, comprising

- a sleeve (10) having, on one side, rotary drive means (12) and, on the other side, a coaxial cavity (13) opening outwards through a circular orifice,

- A gripping mechanism (14) axially movable inside said cavity (13), this mechanism comprising two jaws (15, 16) axially, relative to each other, in a radial plane, remaining

- conformations (20, 20 ') provided at the end of the jaws (15, 16) to allow engagement of the head (1) of the screw, in the spaced apart position of the jaws (15, 16), and then gripping of said head (1) by its peripheral edge with rotationally fastening of said head (1) and said jaws (15, 16), by complementarity of shapes, when said jaws (15, 16) are in the retracted position, at least partially retracted inside said bushing (10), characterized in that it comprises: conversion means able to control the radial translation of the two jaws (15, 16) as a result of an axial displacement of the gripping mechanism ( 14), so as to pass from an open position, in which the two jaws (15, 16) are spaced apart from each other and protrude outside the sleeve (10), to a closed position in which two jaws (15, 16) are retracted and are tucked inside the sleeve (10), The aforementioned conversion means involve:

on the one hand, two axially offset parallel radial pins (30, 31) passing through the cavity of the bushing (10) and engaging respectively in two pairs of coaxial bores provided in the bushing (10),

- on the other hand, at least two radially through oblong holes (32, 33 - 34, 35 - 34 ', 35'), respectively provided in each jaw (15, 16), these oblong holes (32, 33 - 34, 35 - 34 ',

35 ') being arranged in pairs to coincide and defining two radial passages through which the two pins (30, 31) engage respectively.

Each of the oblong holes (32, 33-34, 35-34 ', 35') comprises an axial portion (P ₁ ) followed by an oblique portion (P ₂ ), the oblique portions (P ₂ ) of two oblong holes in coincidence (through which the same pin passes) being oriented opposite each other,

• the transmission of torque between the sleeve (10) and the jaws (15, 16) is provided by the two pins (30,31).

2. End piece according to claim 1, characterized in that the two jaws (15, 16) each have an elongate body terminated, on one side, by a circular flange fraction (19, 26) having the aforesaid conformations (20, 20 ').

3. End piece according to claim 2, characterized in that one of the jaws (16) is of the female type, and in that the other jaw (15) is of the male type and engages sliding in the jaw ( 16) of the female type.

4. End piece according to claim 3, characterized in that the jaw (16) of the female type comprises a body (23) of cylindrical shape provided with an axial cavity (24) of rectangular section, and in that the jaw (15) ) of the male type comprises a body (17) of parallelepipedal shape of section substantially complementary to that of the axial cavity (24) in which it engages and can slide radially.

5. Tip according to claim 2, characterized in that in the retracted position of the jaws (15, 16), the aforesaid circular collar portions (19, 26) extend in the extension of one another.

6. End piece according to one of the preceding claims, characterized in that the two jaws (15, 16) comprise at least two coaxial radial holes (40, 41) oriented perpendicularly to said pins (30, 31) and in which engages a guide axis permitting a radial displacement in translation of the two jaws (15, 16).

7. End piece according to claim 6, characterized in that it comprises a spring (42) generating on the two jaws, a force tending to separate them from each other.

8. Tip according to claim 2, characterized in that, in the retracted position of the jaws (15, 16), the flange portions (19, 26) are at least partially engaged in the sleeve (10).

9. End piece according to claim 1, characterized in that the collar portions (19, 26) of the male and female jaws (15, 16) successively comprise, starting from the body (17, 23), a toothed portion ( 20, 20 ') in the form of a crown sector, this portion toothed being substantially complementary to the serrated peripheral edge of the head (1) of the screw and a smooth cylindrical portion of smaller diameter than that of the toothed portion (20) and preferably equal to the diameter of the cylindrical portion (7) under the head of the opinion.

10. End piece according to claim 2, for a screw (50) whose head has a cap followed by a portion under head (53) of polygonal section which extends coaxially with the screw, characterized in that the fractions of flange (55, 56) each comprise, successively from the body of said jaws:

an annular cavity (59) which extends over a fraction of circumference of diameter substantially equal to the diameter of the cap (52) of the head (51) of the screw (50) and, - an impression (60) comprising two facets (61, 62) extending 90 ° from each other and arranged symmetrically with respect to a bisecting plane passing through the axis of the mouthpiece.

11. Tip according to claim 10, characterized in that the cap (52) of the head (51) of the screw (50) is terminated by a conical ring, and in that the said annular cavity comprises a substantially complementary conical shape the conical crown of the cap (52) of the head (51) of the screw (50).