EP0448666B1 - Assembly for movably mounting a tool on a driving device - Google Patents

Abstract

The assembly comprises a tool holder (3) for a tool (1) such as a punch, a drill or a sewing-machine needle, and a clamping head (4) mounted on the end of a spindle (2), in particular a needle bar. The tool holder comprises an insert which rests on a seat (4a) of the head and is movably supported by it by means of the operation of two jaws (6a and 7a), one of which is provided at one end with two toggle levers (6 and 7) located on the body of the clamping head (4) and subject, at their other end, to a spring which acts to keep the jaws in a clamped position. An accurate positioning of the tool holder on the seat is obtained by the engagement of the upper edge of the tool holder in the bottom of a groove provided in the upper portion of the wall of the seat, and by maintaining this engagement by means of the thrust from tabs (10a and 10b) of a leaf spring (10) fixed to the head (4), against dog points (3f and 3g) of the tool holder (3).

Description

The attachment of very small tools, for example drills, punches, needles or all other types of elongated parts, with a diameter of the order of 1 mm, or even less, on a driving member, for example a spindle or a needle bar, in the case of sewing or embroidery machines, and in a particularly precise predetermined position, represents, for many people, a significant difficulty.

This difficulty is due in particular to awkward handling due to the small size of such objects and, very often, to their generally very pointed shape, therefore to the potential risk of unpleasant or even dangerous injuries if these objects are rusty, which users may incur.

Added to this is that not all people are able to perform such fixing repeatedly with the desired precision and speed.

The above remarks also apply to the replacement of one tool by another, in particular during its breakage or the subsequent execution of other types of work making such replacement essential.

Finally, in view of the often very small dimensions of the tools considered, as is the case with sewing needles, for example, it is obviously difficult to characterize their nature by inscriptions, signs or ideograms which are sufficiently visible, even complete.

With regard to the field of the sewing machine and that of the embroidery machine, it should be added that the housing provided for the insertion of a needle in the flange with which the bar is very often occupies a position whose access is relatively difficult so that it is not uncommon to see users either place the needle in this housing in an incorrect angular position, or not introduce it completely.

As for the risk of injury, mentioned above, this is particularly increased in the case of machines comprising a plurality of needle bars arranged side by side, as is the case. case in embroidery machines as well as in some sewing machines, industrial type or not.

We have already tried to obviate the aforementioned drawbacks, in particular in the field of the sewing machine, by implementing numerous and varied constructions concerning both the fixing of needles on the needle bar of the machine and that cloth presses on their support. Such constructions are notably the subject of patent CH 362,301 and patents of the United States of America 4,359,955; 3,587,498; 3,344,761; 2,985,127; 2,878,765; 2,300,499 and 1,899,303.

The present invention relates more particularly to an assembly for removably mounting a tool on a driving member of the type described in this latter document, that is to say an assembly comprising a tool holder, a fixing head of the tool holder intended for be associated with said member and comprising at least one seat for a corresponding part of this tool holder, a device for holding the tool holder in contact with the seat by said part and means fixing, unequivocally, the relative position of the head fixing and the tool holder when the latter is subject to the holding device, assembly in which said unequivocal positioning means comprise at least one stop member preventing any movement of the tool holder on the seat at least in a determined direction , stop members preventing any movement of this tool holder on said seat according to any one of the trajectories transverse to said determined direction , and at least one thrust member acting on the tool holder in the direction of maintaining it in permanent contact with said stop member, that is to say in said unequivocal position relative to the fixing head.

In addition to the fact that it makes it possible to obviate the various drawbacks mentioned, the assembly according to the invention lends itself particularly well to a miniaturized execution of the fixing head, and especially of the tool holder, which is hardly the case with the device which is the subject of US patent 1,899,303. In particular, such a tool holder may have dimensions of comparable size to that of the tool, in particular a needle sew, therefore very weak, while being sufficient to allow easy gripping by the fingers of the user.

The essential characteristics of the assembly according to the invention are the subject of claims 1 to 14.

• la figure 1 en est une élévation de face;
• la figure 2 une vue de côté;
• la figure 3 est une vue similaire à celle de la figure 2 avec coupe partielle selon III - III de la figure 1;
• la figure 4 est une vue en coupe selon l'axe IV - IV de la figure 6;
• la figure 5 est une coupe de détail, selon V - V de la figure 3;
• la figure 6 est une coupe selon VI - VI de la figure 2;
• la figure 7 est une vue de dessous, selon VII - VII de la figure 1;
• la figure 8 est une vue de face d'un élément de la fig. 4;
• la figure 9 est une coupe selon IX - IX de cette figure 4;
• les figures 10, 11A et 11B illustrent des variantes d'exécution d'une partie essentielle de l'ensemble selon l'invention;
• la figure 12 est une vue de face d'une autre variante d'exécution d'une telle partie;
• la figure 13 est une élévation latérale montrant une autre utilisation possible de l'ensemble selon l'invention.

The attached drawings show, by way of example, an embodiment and variants of such an assembly applied to the field of the sewing or embroidery machine:

• Figure 1 is a front elevation;
• Figure 2 a side view;
• Figure 3 is a view similar to that of Figure 2 with partial section along III - III of Figure 1;
• Figure 4 is a sectional view along the axis IV - IV of Figure 6;
• Figure 5 is a detail section, along V - V of Figure 3;
• Figure 6 is a section on VI - VI of Figure 2;
• Figure 7 is a bottom view, along VII - VII of Figure 1;
• Figure 8 is a front view of an element of FIG. 4;
• Figure 9 is a section on IX - IX of this Figure 4;
• Figures 10, 11A and 11B illustrate alternative embodiments of an essential part of the assembly according to the invention;
• Figure 12 is a front view of another alternative embodiment of such a part;
• Figure 13 is a side elevation showing another possible use of the assembly according to the invention.

The assembly shown in the drawings is intended to ensure the removable fixing of a elongated piece, for example a sewing needle, of which only the upper section 1 is visible in the drawing, at the lower end of a needle bar 2 of sewing or embroidery machine, partially illustrated.

The functional elements that such an assembly comprises are however such that it is perfectly adapted to support all types of "tools", even of small size, and can therefore be the object of applications as diverse as numerous, in particular all those in which a tool must be able be fixed to a support by simple manual action, quickly and removably, in a predetermined position, with particularly high precision.

Thus, although the description which follows will relate to an application of the principle of the invention to a sewing or embroidery machine, it will be understood that the structural elements which will be described may be adapted, as to their shape, their dimensions or still the materials which constitute them, to any other practical application which would be, by nature, likely to give rise to the disadvantages noted previously.

In essence, the assembly shown comprises a tool holder and a fixing head indicated generically by the references 3 and 4, respectively (Figures 1 and 2).

The tool holder 3 is constituted here by a generally elongated plate, partially rectangular, in synthetic material for example, the front face of which, in the drawing, has, on the one hand, a boss 3a, arranged in a slightly off-centered position on the right relative to the longitudinal axis of symmetry of the plate (Figure 1) and, on the other hand, two rectangular notches 3b and 3c formed along the left and right edge, respectively, of the plate. The usefulness of the notches 3b and 3c will appear later.

As for the boss 3a, it is crossed by a threaded passage 3d, communicating with a straight blind opening 3e (Figures 1 and 5) in which is inserted the punch 1 that a screw 5, engaged in the passage 3d, allows axially block at its end. As a result, the punch is removably fixed in the tool holder 3 and can therefore be easily replaced by simply unscrewing the screw 5 and screwing it back subsequent to the insertion of another punch, for example in the opening 3rd.

Below the boss 3a, the tool holder has two cylindrical pins 3f and 3g projecting symmetrically, on either side of the plate 3 and whose usefulness will appear later.

On the upper part of its rear face, the tool holder has, on the one hand, a 3-hour recess in the form of a bowl, and, on the other hand, a cutout 3i.

It will also be noted that the upper edge 3k of the tool holder 3 has a semi-circular section profile over its entire length.

In the fixing position on the head 4, the tool holder 3 is engaged by its rectangular part in a seat of homologous shape, 4a, cut out on the front face of the head (FIGS. 1 and 4), seat in which the holder tool is blocked by the action of two jaws 6a and 7a which are inserted into the notches 3b and 3c already mentioned, under the action of a spring 8 stretched between the rear ends of two levers 6 and 7 of which these jaws constitute the ends earlier (Figures 1 and 6).

As can be seen in the drawing (FIGS. 2 and 6), the levers 6 and 7 are partially engaged in corresponding cutouts 4b and 4c, formed on the lateral faces of the head 4 and communicating, at the rear of the latter, by a window 4d delivering passage to the spring 8.

These levers are articulated on vertical axes 9a and 9b (Figures 2, 3, 6 and 7) driven into corresponding housings formed in the body of the head 4 and passing respectively through the cutout 4b, for the first axis, and the cutout 4c , for the second (Figures 3 and 6).

It should be noted at this point that the front part of the jaws 6a and 7a is cut in the form of a bevel with a slightly rounded profile; correspondingly, the rear part of the lateral faces of the tool holder 3 also has a bevel profile of similar inclination (FIG. 6).

This particular configuration, both of the jaws 6a and 7a and of the tool holder, is essentially intended to allow, if necessary, to control the spacing of these jaws during the introduction of the tool holder into the seat 4a of the head 4 : Indeed, when the tool holder is brought into contact with the jaws 6a and 7a by its bevelled parts, it will suffice to exert a slight pressure on the tool holder so that these jaws move apart against the action of the spring 8 already mentioned and let the tool holder engage in the seat 4a of the head 4.

It will also be noted that the height of the jaws 6a and 7a (FIG. 1) is less than the length of the two rectangular notches (3b, 3c) with which the tool holder 3 is provided.

This is because, in the embodiment shown, these jaws ensure in fact only the maintenance of the tool holder on the head but not its positioning: the latter is the result of the cooperation of various organs which will now be described.

The cutouts 4b and 4c already mentioned delimit, in fact, two spoilers 4e and 4f (Figure 1) whose underside has a partially rounded profile and which delimit, in cooperation each with one of the two legs 10a and 10b that has a leaf spring 10, a recess in which the cylindrical pin 3f of the tool holder 3 takes place, between the spoiler 4e and the tab 10a, and the pin 3g, between the spoiler 4f and the tab 10b of the leaf spring 10 ( Figures 1 to 3, 8 and 9).

This blade 10 is fixed to the bottom of the seat 4a of the head 4 by a screw 11 engaged in a threaded passage 4g made in the head and communicating with a vertical housing 4h in which the lower end of the spindle 2 is introduced. note that the screw 11 is also used for fixing this pin in the housing 4h of the head 4.

At its upper part, the blade 10 also has a curved tongue 10c which engages in the cutout 3i of the tool holder 3 when the latter is positioned as illustrated in FIG. 4.

It will also be noted that the upper edge of the recess constituting the seat 4a of the head 4 is constituted by the bottom of a groove 4i, with semi-cylindrical profile, of radius corresponding to that of the upper edge 3k of the tool holder 3 .

Furthermore, and as this appears clearly in FIG. 4, the difference in level between the upper part of the edge 3k and the upper part of one or the other cylindrical stud (3f and 3g) of the plate 3, corresponds substantially to the difference in level between the portion of the bottom of the groove 4i occupying the highest position and the horizontal portion of the underside of the spoilers 4e and 4f.

Therefore, the introduction of the tool holder 3 in the seat 4a of the head 4 can be carried out in a safe and easy manner: it suffices, in fact, to start by placing this tool holder in the inclined position sketched in broken lines in FIG. 4 by inserting its rounded upper edge in the groove 4i of the head 4.

The tool holder is then tilted in direction F (fig. 4) while spreading the jaws 6a and 7a, either by proceeding in the manner already described, or by tightening the levers 6 and 7 against the action of the spring 8, then release these as soon as the tool holder reaches the vertical position visible in the drawing, in which the pins 3f and 3g are placed between the spoilers 4e and 4f and the legs 10a and 10b of the leaf spring 10 It should be noted that these are profiled in such a way that they are then slightly bent in a clockwise direction so that they exert a slight vertical pressure on the tool holder and thus ensure that it is held in a perfectly defined axial position, pressing against the bottom of the groove 4i.

Furthermore, precisely because, once the tool holder 3 fixed to the head 4 in the manner described above, the tabs 10a and 10b of the leaf spring 10 are bent elastically, as soon as the jaws 6a and 7a are open by action on the levers 6 and 7, these tabs relax and provide for the lateral ejection of the tool holder 3 and of the tool 1 associated therewith.

Although in the preceding description, only the case where the jaws of the head 4 have only the function of ensuring that the tool holder is kept in a position which is fixed by the engagement of the upper edge 3k of this tool holder in the groove 4i of the head, on the one hand, and the elastic action exerted by the tabs 10a and 10b on the pins 3f and 3g, on the other hand, it would be possible, in a variant not shown, to entrust this positioning function exclusively to the jaws 6a and 7a: for this purpose, it would suffice to size these jaws so that they engage in the notches 3b and 3c without any play, the height of the first corresponding substantially to the length of the others.

In another alternative embodiment of the present invention (FIG. 10), the tool holder and the tool could form a non-removable whole, the punch 1 being driven into the passage 3e of the tool holder, or even being fixed in this by overmolding, especially if the tool holder is made of injected plastic.

At this point, it should be noted that, with an embodiment of this type, it is important to prevent the user from being able to mount the tool holder upside down, that is to say with its front face. turned backwards, in particular because, in such a case, the fixing of the tool holder in the seat of the head 4, particularly by the action of the jaws 6a and 7a, could only be imperfect.

This possibility is made impossible thanks to the presence of a "polarizing device" formed by the tongue 10c of the leaf spring 10 and by the cutout 3i with which the upper part of the tool holder 3 is provided: if the tool holder is engaged in the seat of the head 4 with its cutout 3i facing the head, the tongue 10c will penetrate this cutout without opposing this engagement. If, on the other hand, we try to do the same by presenting the tool holder upside down, that is to say in a position such that the cutout 3i is located at the front, the tool holder will come up against against the tongue 10c and cannot be engaged in the groove 4i of the head 4.

As a variant, the keying device could consist exclusively of the screw 11 projecting into the recess 3h of the plate.

More generally, the polarization may be formed by any element, projecting into the bottom of the seat 4a, and by a corresponding recess provided on the back of the plate 3, recess in which this element will be placed if the plate is inserted. correctly: this element will, on the contrary, constitute an obstacle to such insertion if the user tries to insert this plate upside down.

It should also be noted that, in addition, the user will be able to realize visually that he will mount the tool holder upside down or upside down: indeed, the front side this will generally be covered with inscriptions, signs or ideograms corresponding for example to a trademark and / or a codification characteristic of the tool considered.

The positioning of the tool holder 3 in the seat 4a of the head 4, in particular by prior engagement of the upper edge 3k in a groove 4i made in the head, can be obtained, in a completely similar manner, by conformations of the head 4 structurally quite different from that described with reference to FIG. 4, in particular.

Thus, in the alternative embodiment of FIG. 11A, the seat intended for the tool holder 3 is formed by a simple vertical surface formed on the front part of the head 4 and that the positioning of this tool holder is ensured by contact of its upper edge with a horizontal rod 4i ′ secured to the head 4, fixed on the latter at a distance from the seat less than the thickness of the tool holder.

As can be seen in the drawing, this very simple architecture makes it possible to mount the tool holder 3 on the head 4 in the same way as described above, that is to say by first placing the tool holder in the position illustrated in phantom and by tilting it clockwise while keeping it in permanent contact with the rod 4i '.

In the variant of FIG. 11B, the upper edge of the tool holder 3 is cut in a bevel and is intended to be engaged in a groove 4i '', of substantially triangular cross section, formed in the head 4, at the upper end of the seat intended to receive the tool holder. This groove has an angular amplitude of value greater than that of the inclination of the bevel that forms the upper edge of the tool holder so as to allow, first, an easy insertion of this edge (as in the representation in phantom) of the tool holder) in the groove 4i '' without having to move the jaws 6a and 7a beforehand, then an easy engagement of the tool holder 3 between these jaws (position illustrated in solid lines).

It will be noted that, thanks to this particular type of construction, the tool holder can in no case be disposed at upside down with respect to the arrangement illustrated in FIG. 11B, the back of the beveled portion of the tool holder abutting against the extreme right edge of the groove 4i ''.

Of course, other arrangements and shapes of the upper edge of the tool holder 3 and of the blocking member (4i, 4i ', 4i' ') thereof on the head 4 are possible without, however, leaving the part of the present invention.

Furthermore, it is obvious that the maintenance of the tool holder on the seat of the head could be ensured by any removable locking device, structurally even very different from that constituted by the levers 6 and 7, the jaws associated with them and the clamping spring 8, as described with reference to the accompanying drawings.

Finally, it should be noted that, although in the above description and in the drawings to which it refers, only the case of fixing a needle of the conventional type for a sewing or embroidery machine has been envisaged, it is obvious that the invention is not limited to such a particular use and that it can also allow the attachment of other types of tools, in particular "multiple" needles or "presser" needles of the kind represented in FIG. 12 (whose functional features are well known to those skilled in the art, in particular by the patents of the FRG 72,170 and Swiss 298,848) and even the fixing of the stuffing box of the machine on an appropriate support (FIG. 13).

In FIG. 12, the fabric presser p is formed by a sleeve, for example made of synthetic material, mounted to slide on the body of the needle 1 and subjected to the action of a spring r stretched between the fabric presser itself. - same and the lower part of the needle holder 3.

In FIG. 13, we see a stuffing press comprising a sole 31 articulated at 32 on a support 23, the upper part of which is shaped identically to the tool holder 3 described above, and which is fixed to a fixing head 24 whose the structural elements correspond, at all points, to those of the fixing head 4, also already described.

Therefore, the homologous elements appearing on the FIG. 13 of the drawing have been indicated by references corresponding to those visible in FIG. 2, increased by the value 20.

The fixing head 24 is fixed to the lower end of a vertical bar 22, partially shown and extending parallel to the needle bar 2 * of the sewing machine, bar traditionally provided with a flange 4 * to which a 1 * needle is removably attached.

It is however obvious that a fixing head of this type could very well be mounted on a support other than a bar such as bar 22: it could, for example, be fixed to the free end of the lever 70, respectively 170 , appearing in FIG. 1, respectively in FIG. 7, of the drawings of the application EP 0 378 965 concerning a "press-stuffing device for a sewing machine", published on July 25, 1990 and to which reference will be made for more details. .

It is advisable, at this point, to note a particularly important advantage which can be obtained thanks to the tool holder shown in FIGS. 1 to 9, especially when the tool must be placed on the tool holder in an axial position and / or very precise angular which must be determined prior to its implementation, which is for example the case for a sewing or embroidery machine needle. Indeed, this determination can be made while the tool holder is not yet attached to the spindle, which is particularly advantageous whenever such a spindle is naturally difficult to access. In addition, the user can build up a reserve of the same tools adapted in the same way on tool holders specific to each tool in the reserve and usable as spare parts without significant interruption of the operation to be carried out thanks to the type of the tool in question.

In general, the assembly described and shown lends itself particularly well to fixing, on a driving member, for example a needle bar, of any other type of part, whether it itself constitutes a tool or, more simply , a fixing rod of any device to be associated, at least momentarily, with the driving member.

Claims (15)

1. An assembly for detachably mounting a tool (1) on a driving member (2), comprising a tool holder (3), a mounting head (4) for the tool holder intended to be connected to the said driving member and comprising at least one seat (4a) for a corresponding part of the said tool holder, a device (6, 7) for retaining contact of the said part of the tool holder (3) with the seat, and means locating at a unique position the mounting head (4) relative to the tool holder (3) when the latter is secured to the retaining device (6, 7), an assembly in which the said means for unique location comprise at least one stop member (4i) preventing any displacement of the tool holder (3) on the seat (4a), at least in one specific direction, abutment members preventing any displacement of the said tool holder (3) on the said seat (4a) in any path transverse to the said specific direction, and at least one thrust member (10a, 10b) acting on the tool holder (3) so as to keep it in permanent contact with the said stop member, thus at the said unique location in relation to the mounting head, the assembly characterised firstly in that the mounting head is formed by a body, at least part of the external surface of which is hollowed out by a recess which has a substantially parallelepipedal general shape and which is open at one end, at least part of the base of the recess forming the said seat (4a), at least part of the longitudinal walls of the recess forming the said abutment members, and at least part of the wall of the recess, delimiting the other end of the said recess, forming the said stop member (4i), and secondly in that the tool holder (3) has the general shape of a parallelepipedal plate of a width substantially corresponding to the width of the recess provided in the mounting head (4), a first end of this plate being intended to be brought into contact with the said stop member (4i).
2. An assembly according to claim 1, characterised in that the plate (3) has a recess (3e) intended to receive the tool (1) and opening onto a portion of the plate opposite the said first end thereof, and means (3a, 3d, 5) enabling the tool to be fixed detachably to the plate.
3. An assembly according to claim 1, characterised in that the plate has a recess in which the tool is engaged, the latter being rendered integral with the plate by moulding the material forming the plate onto at least one portion of the tool.
4. An assembly according to claim 2 or 3, characterised in that the said thrust member is formed by at least one resilient element (10) inserted between the body (4) and a portion of the plate (3) located opposite its first end, this element being arranged and disposed so as to be brought into a stressed state by the action of the tool holder when the latter is placed on its seat at the said unique location.
5. An assembly according to claim 4, characterised in that the plate (3) has at least one stud (3f, 3g) projecting from at least one of the surfaces of the said plate, and in that the said resilient element (10) engages on this stud.
6. An assembly according to claim 5, characterised in that the said element (10) is formed by a distal portion of a resilient blade covering at least part of the base of the recess of the body of the mounting head and integral with the said body.
7. An assembly according to claim 6, characterised in that the plate (3) has two studs (3f, 3g) projecting from the side surfaces of the plate, and in that the blade (10) comprises two resilient elements (10a, 10b) intended to co-operate with the first (3f) and the second (3g) studs respectively.
8. An assembly according to claim 1, characterised in that it comprises at least one fool-proof device (3i, 10c) intended to prevent the plate (3) from being arranged in the recess (4a) of the body of the mounting head in a different position from that enabling the plate to be placed at the said unique location.
9. An assembly according to claim 8, characterised in that the fool-proof device is formed by at least one projecting element (10c) provided on the base of the recess (4a) of the body of the mounting head (4), and by a cavity (3i) which is provided in a portion of the plate (3) and has a position corresponding to that of the projecting element, the latter being capable of entering the cavity when the plate is introduced into the said recess in a position corresponding to that enabling it to be placed at the said unique location.
10. An assembly according to claim 9, characterised in that the blade (10) has a tongue (10c) projecting from the base of the recess (4a) of the body of the mounting head (4), and in that the surface of the plate intended to co-operate with the said seat has an indentation (3i) arranged so as to allow the said tongue to penetrate into the interior of the said indentation freely, at least when the plate occupies the said unique location.
11. An assembly according to claim 1, characterised in that the end of the plate (3) intended to be brought into contact with the part of the wall of the recess (4a) of the body (4) of the mounting head forming the said stop member has a semi-cylindrical section, the said part of the wall having a groove of a shape corresponding to that of the said section.
12. An assembly according to claim 1, characterised in that the retaining device comprises at least one gripper, which consists of two jaws (6a, 7a) and is integral with one of the said elements, tool holder (3) or mounting head (4), for securing the said element to at least one portion of the other element, at least one first resilient means (8) causing the gripper to tighten with sufficient force to ensure the said securing action, and members (6, 7) which enable the gripper to be opened in opposition to the said resilient means in order to separate the tool holder from the mounting head by countering the securing action.
13. An assembly according to claims 2 and 12, characterised in that the gripper (6a, 7a) is integral with the body of the mounting head (4), in that the said gripper is arranged in such a manner that when the gripper is in the tightened position, at least one end portion of its jaws projects from the interior of the recess (4a) of the mounting head along the two longitudinal walls of the recess, and in that the longitudinal edges of the tool holder each have a slot (3b, 3c), one of which is intended to receive the projecting portion of the first jaw (6a), and the other the corresponding portion of the second jaw (6b) of the gripper.
14. An assembly according to any one of the preceding claims, characterised in that the surface of the plate opposite that intended to be brought into contact with the seat of the mounting head is covered with inscriptions and/or signs and/or ideograms characteristic of the nature and/or the characteristics of the tool with which it is integral.
15. A sewing machine or an embroidering machine comprising at least one assembly according to any one of claims 1 to 14, connected to the needle bar (2, 2*) and/or the presser-foot device (22) of the machine.

Images