FR2843062A1 - Gripper sleeve for fastener driver has shaft with movable jaw mounted in end bore and O-ring to retain jaw - Google Patents

Abstract

The gripper sleeve for a fastener driver has a tubular shaft (10) and a jaw (16) partially engaged in an axial bore formed in the end of the shaft. The jaw has an L-shape with the horizontal branch extending radially of the sleeve axis and the vertical branch extending axially. Adjacent to the opening in the shaft is a radially inwardly extending tooth (20). The jaw is retained by an O-ring (22) fixed to the shaft and engaging the vertical branch of the jaw.

Description

The present invention relates to a gripping and screwing tip

  usable on a screwing device such as, for example, a

Motorized screwdriver / unscrewer.

  It applies more particularly, but not exclusively, to screws comprising a head having at its periphery conformations intended to cooperate with a screwing tool to exert on the screw a torque of screwing and a portion under cylindrical head whose diameter is lower than that of the head, but greater than that of the threaded rod of the screw, the connection between this cylindrical portion with the periphery of the head and with the end of the rod

  carried out by means of radial shoulders.

  However, it also applies to conventional type screws comprising a head shaped so as to be able to be driven by a screwing tool, this screw being fitted with a washer placed under the head, at least part of which has a smaller diameter. to that of the head. This washer may be rigid and be shaped so as to prohibit the unscrewing of the screw when the latter is screwed. It may have a stepped profile and / or be made of a deformable material to constitute for example a seal. -2 In patent application FR No. 02 09632, the Applicant has proposed a gripping and screwing bit for screws of the aforementioned type, this bit comprising a socket capable of being rotated and having at one of its ends a coaxial cavity opening to the outside so as to be able to receive the head of the screw. The inner surface of the socket which delimits this cavity has at least one conformation capable of engaging with that of the head of the screw.

  so as to be able to transmit a tightening torque.

  This tip also comprises gripping means designed so as to engage in the space between the two shoulders of the head of the screw (or in the space under the head delimited by the washer) to come into

  taken on the above cylindrical portion (or on said washer).

  Thanks to these provisions, the rotary drive function is ensured

  separately from the gripping function.

  The drive function is directly ensured by the tip socket, which can be shaped like a conventional pipe wrench, and therefore have a minimum thickness, taking into account the torque it must

exercise on the screw.

  The gripping means no longer having a rotary drive function, may consequently have reduced dimensions without, however,

lose efficiency.

  The centering means can be provided both by the sleeve and by the gripping means: this arrangement makes it possible to use screws with relatively flat heads which would risk swiveling slightly in a bit of

classic screwing.

  -3 In this case, the action of the gripping means on the cylindrical part under

  head confirms this centering at the end of insertion of the screw into the socket.

  The invention therefore more particularly aims to improve the characteristics of the structure described above to obtain a gripping and screwing tip of relatively simple design, not bulky (short length, small diameter) and yet very efficient and

inexpensive.

  It proposes, for this purpose, a gripping and screwing tip comprising a socket, of substantially cylindrical shape able to be driven in rotation and having at one of its ends a coaxial cavity opening to the outside so as to being able to receive the head of a screw, the internal surface of the sleeve which delimits this cavity having at least one conformation capable of coming into engagement with a corresponding conformation of the head of the screw,

  so as to be able to provide a tightening torque.

  According to the invention, this endpiece further comprises gripping means involving a jaw partially engaged in an axial slot made in the said end of the sleeve, this jaw having a substantially L-shaped whose horizontal branch extends radially in direction of the axis of the nozzle while the end of the vertical branch of the L which extends axially comprises in the vicinity of the orifice of the nozzle a tooth which extends radially inwards, this jaw being retained by elastically deformable means, integral with the sleeve and engaging on the vertical branch of the L. These elastically deformable means may include means for

  pivoting, radially movable, which engage through the aforesaid slot.

  Advantageously, this axis of rotation may include a rod which engages in a coaxial annular groove formed in the sleeve at the level of the slot and in a notch, preferably semi-cylindrical provided in the branch.

vertical of the jaw.

  Furthermore, the end piece may further comprise a pivot constituted by a cylindrical rod comprising a threaded end intended to be screwed into a coaxial threaded bore, opening into the bottom of the socket cavity opposite its orifice, and a cylindrical head secured to its other end, this head delimiting with said bottom an annular space in which

  engages the horizontal branch of the jaw with a slight axial play.

  Thanks to these arrangements, the head of the screw can come to engage in the socket cavity by pushing back the jaw which swings slightly while elastically deforming the rod. At the end of engagement, the tooth engages under the head of the screw while, under the effect of the elasticity of the rod, the jaw returns to its initial position. Embodiments of the invention will be described below, by way of nonlimiting examples, with reference to the appended drawings, in which: FIG. 1 is a front view of a gripping and screwing end piece in which is engaged the head of a screw; Figure 2 is an axial section along A / A 'of the nozzle shown in Figure 1; Figure 3 is a perspective view of the socket of the screwdriver bit illustrated in Figures 1 and 2, Figure 4 is a perspective view on a larger scale of a jaw of the screwdriver bit; Figure 5 is an enlarged view of the pivot of the nozzle; Figure 6 is an enlarged side view of the screw of the

figure 2.

  In the example shown in these drawings, the screwing tip 1 has been specially designed for a screw 2, the head of which has been shown in FIG. 6, it being understood that, as previously mentioned, the invention is not limited

not a particular type of screw.

  In this example, the screw 2 comprises a head 3 having a domed upper face 4 with, in the center, an injection bowl. Of course, the presence of this bowl only exists in the case where the head is molded. On the other hand, in the case of forging, for example cold forging by rolling, the upper face 4 of the head 3 will be continuously curved. The peripheral edge 5 of the head 3 is serrated and here comprises fifteen teeth 6 separated by

  notches forming an angle of about 1170.

  This head 3 is connected to a coaxial rod 7, via a cylindrical portion under the head 8 whose diameter is substantially equal to the distance between the bottom of the notches and the axis XX 'of the screw. The height of the cylindrical portion 8 is here substantially equal to the height of the head 3. The diameter of the rod 7 of the screw, at its connection to the cylindrical portion 8, is much less than that of the head 3 ( about 50%). The connection between the cylindrical portion 8 with the periphery 5 of the head 3 and with the end of the

  rod 7 effected by radial shoulders RI, R2.

  -6 Of course, this screw 2 can be screwed using a hand tool having a tubular tip whose internal profile corresponds to the external shape.

serrated head 3.

  However, it is particularly suitable for the screwdriver bit illustrated in FIGS. 1 to 5 which essentially comprises a tubular sleeve 10, of cylindrical external shape, closed on one side by a bottom 11, extended coaxially by a rod 12, of hexagonal section, intended to engage in

the chuck of a screwdriver.

  This socket 10 has, on the side opposite to the tigel2, a coaxial cavity 13 open on the side opposite to the bottom II and having a cross section with serrated profile (teeth 14) substantially complementary to that of the head 3 of the

screw 2.

  At the opening of the cavity 13, the sleeve 10 includes an internal chamfer 14 intended to guide and center the head 3 of the screw 2, during its introduction and an external chamfer 15 provided to avoid the presence a protruding edge which could damage the part that is to be screwed, in the case where the axis of the screw is not strictly perpendicular to the face

outside of this room.

  In this example, the sleeve 10 comprises two radial intersecting slots FI, F'1 - F2, F'2, 900 from one another, produced by sawing from the opening of the cavity 13 as far as the bottom 11. These slots FI, F'1 - F2, F'2 produce in the tubular part four portions of slot FI, F'1 - F2, F'2 diametrically

opposite two by two.

  In each of these slot portions FI, F'1 - F2, F'2 engages a jaw 16 more particularly visible in FIG. 4 which consists of a tongue -7 of thickness substantially equal to the width of the slot portions FI, F'1 - F2, F'2 and which is cut so as to have a shape substantially in L. The end of the vertical branch 17 of this jaw 16 has, on the one hand, on the side opposite to the branch horizontal 18 a tooth 19 with an angular profile oriented towards the inside of the cavity 13, the upper face 20 of which extends in the extension of the chamfer 14 from the orifice of the socket 10, and on the other hand, to the opposite of the tooth 19, a protuberance 21 comprising an oblique upper face which extends in the extension of the chamfer 15 of the sleeve 10 and

a radial face.

  The horizontal branch 18 of the jaw 16 has a relatively large height (about 1/3 of the height of the jaw 16, with rounding in the angular regions of its upper part. Its rear face comprises a semi-cylindrical notch 21 into which can come engage an elastic ring 22 disposed in an annular groove 23 formed in the cylindrical outer wall of the sleeve 10, when the jaw 16 is engaged in its

slot portion FI, F'1 - F2, F'2.

  Furthermore, the screwing tip further comprises a pivot 24 constituted by a cylindrical rod having a threaded end 25 intended to be screwed into a coaxial threaded bore opening into the bottom 11 of the cavity 13 of the sleeve 10. This pivot 24 comprises a cylindrical head 27 integral with its other end which delimits with the bottom an annular space in which engages the horizontal branch 18 of the jaw 16, with a slight axial clearance, the end of this branch coming into abutment on the pivot 24 under the effect of the elastic ring 22. The space between the upper face of the head 27 and the base of the teeth 20 of the jaws 16 corresponds substantially to the thickness of the head 3 of

  the screw (between the curved face 4 and the shoulder Ri).

  -8 Thanks to these provisions, in order to carry out the screwing or unscrewing of the screw 2, the head 3 of the screw 2 is engaged in the cavity 13 so that the toothing of the head 3 comes into engagement with the corresponding teeth of the

socket 10.

  During this engagement, the head 3 of the screw 2 comes to bear on the upper face of the tooth 20 and causes a displacement (translation + rotation) of the jaw 16, causing an elastic deformation of the rod 22. Once the head 3 passed between the jaws 16, these close by engaging on the cylindrical portion under head 8 of the screw 2. The convex face 4 of the head 3 of the screw 2 then comes to bear on the head 27 of the pivot 24 and is retained without play thanks to the action of the lower face 20 of the tooth on the lower edge of the

head 3.

  The screw 2 is then correctly maintained and centered relative to the end piece. The screwing can therefore be carried out correctly. During this screwing: - the serrated profile of the socket 10 is engaged with that of the head 3 of the screw 2 so as to be able to transmit a screwing torque to it, - the jaws 16 do not come out of the socket 10 and do not can therefore not damage the workpiece; it is the same for the teeth of the sleeve 10 which end in the chamfer 14 (completed by the upper face of the teeth 20), - the centering of the screw is ensured both by the engagement of the serrated profiles of the socket 10 and head 3 of screw 2 and by the action of the teeth against the cylindrical portion under head 8 of screw 2, - the jaws 16 do not participate in the rotational driving of the screw and therefore do not undergo no significant constraints, owing to the fact that the rotation of the screw is directly ensured by the sleeve 10, the tubular form of this is optimally used

  socket to transmit the tightening torque.

  -9 The disengagement of the screw, out of the socket, is carried out by a process opposite to the previous one by exerting a tensile force between the screw and the socket. Under the effect of this traction, the edge of the head 3 exerts on the teeth 16 a force causing a separation of the jaws 16 which allows the passage of the head 3 of the

screw 2.

  Once the screw 2 is extracted, the jaws 16 return to their initial position

for a new use.

  In the example previously described, the socket 10 is protected by a tubular cover 28, of cylindrical shape, coming to be screwed on a thread provided for

  level of the junction between the bottom l l of the socket 10 and of the rod 12.

  Similarly, the pivot 24 may be provided interchangeable to be able to adapt

  the nature and dimensions of the head 3 of the screw 2.

  Of course, the invention is not limited to the embodiment described above. Thus, the screw 2 could have a head 3 with a smooth edge and with a coaxial concave imprint (for example a cruciform imprint). In this case, the internal (cylindrical) surface of the sleeve 10 could be smooth while the head 27 of the pivot 24 could include a projecting shape, complementary to that

of the concave footprint.

  Similarly, the screw 2 may be of the conventional type. In this case, a washer

  (corresponding to the cylindrical portion under the head) must be provided.

  - 10 In the case where this washer is deformable, which is the case with a sealing washer, an advantage of the solution according to the invention consists in that

  an automatic disengagement of the end piece 1 is obtained at the end of screwing.

  Likewise, the rod 12 of the end piece 1 can be secured to the rod of the pivot 24 so as to constitute a unit mounted to slide in the sleeve 10 with spring return to the normal position of use. Of course, this set

  will be shaped so as to ensure the rotation drive of the sleeve 10.

- he

Claims (13)

claims   1. A gripping and screwing end piece usable on a screwing device, this end piece (1) comprising a socket (10), of substantially cylindrical shape, capable of being driven in rotation and having a coaxial cavity at one of its ends. (13) opening to the outside so as to be able to receive the head (3) of a screw (2), the interior surface of the sleeve which delimits this cavity (13) having at least one conformation capable of coming into taken with a corresponding conformation of the head (3) of the screw (2), so as to be able to transmit a tightening torque, characterized in that it also comprises gripping means involving a jaw (16) partially engaged in an axial slot (FI, F'1 - F2, F'2) produced in the aforementioned end of the sleeve (10), this jaw (16) having a substantially L-shape whose horizontal branch (18) extends radially towards the axis of the nozzle (1) while the end of the vertical branch (17) of the L which extends axially comprises in the vicinity of the orifice of the socket (10) a tooth (20) which extends radially inwards, this jaw (16) being retained by elastically deformable means, integral with the sleeve (10), and engaging on the vertical branch (17) of the L. 2. End piece according to claim 1, characterized in that the above elastically deformable means comprise means for pivoting radially mobiles that engage   through said slot (FI, F'1 - F2, F'2).   3. End piece according to claim 2, characterized in that the aforesaid pivoting means comprise a rod (22) which engages in a coaxial annular groove (23) formed in the bush (10) at the level of the slot (FI, F'1 - F2, F'2) and in a notch (21), preferably semi-cylindrical provided in the vertical branch (17) of the jaw (16).   4. End piece according to one of the preceding claims,   characterized in that it comprises a pivot (24) constituted by a cylindrical rod comprising a threaded end (25) intended to be screwed into a coaxial threaded bore, opening into the bottom (11) of the cavity (13) of the socket (10), opposite its orifice, and a cylindrical head (27), integral with its other end, this head (27) delimiting with said bottom (11) an annular space in which the horizontal branch engages (18) bit (16) with a slight axial play.   5. End piece according to one of the preceding claims,   characterized in that the aforesaid cavity (13) has a cross section with a profile   serrated substantially complementary to that of the head (3) of the screw (2).   6. End piece according to one of claims 1 to 4,   characterized in that the inner surface of the sleeve (10) is smooth, and in that the head (27) of the pivot (24) comprises a projecting shape, complementary   of a concave shape provided in the head (3) of the screw (2).   7. End piece according to one of claims 4 to 6,   characterized in that the pivot (24) is interchangeable so that it can   adapt the end piece (1) to the shape and dimensions of the screw (2).   8. End piece according to one of the preceding claims,   characterized in that the rod (12) of the end piece (1) can be secured to the rod of the pivot (24) so as to constitute an assembly mounted to slide in   the bush (10) with spring return to the normal position of use. - 13   9. End piece according to one of the preceding claims,   characterized in that, at the opening of the aforesaid cavity (13), the sleeve (10) comprises chamfered inner and outer edges, and in that the jaw comprises oblique faces extending in the extension of said edges chamfered.   10. End piece according to one of the preceding claims,   characterized in that the end of the vertical branch of the jaw has, on the one hand, on the side opposite to the horizontal branch, a tooth with an angular profile oriented towards the inside of the cavity, the upper face of which extends in the extension of the chamfer of the orifice of the socket and, on the other hand, opposite the tooth, a protuberance comprising an oblique upper face which   extends in the extension of the chamfer and a radial face.   1 1. End piece according to one of the preceding claims,   characterized in that the horizontal branch of the jaw has a relatively large height (about 1/3 of the height of the jaw), with rounding in the angular regions of its upper part, and in that the rear face of the jaw comprises a notch semi-cylindrical (21) into which an elastic ring (22) can be engaged, disposed in an annular groove (23) produced in the cylindrical external wall of the sleeve (10), when the jaw (16) is   engaged in its slot portion (FI, F'1 - F2, F'2.).   12. End piece according to one of the preceding claims,   characterized in that the aforesaid screw (2) comprises a head (3) having at its periphery conformations intended to cooperate with a screwing tool to exert on the screw a screwing torque and a portion under cylindrical head whose diameter is smaller to that of the head but greater than that of the threaded rod of the screw, the connection between this cylindrical portion with the periphery of the head and with the end of the rod being effected by means of radial shoulders. - 14   13. End piece according to one of claims 1 to 10,   characterized in that the screw (2) is of the conventional type and comprises a head shaped so that it can be driven by a screwing tool, this screw being equipped with a washer placed under the head, at least part of which   has a smaller diameter than that of the head.   14. End piece according to claim 13,   characterized in that the washer has a stepped profile.   15. End piece according to one of claims 13 and 14,   characterized in that the washer is made of a deformable material.