ITMI20000718A1 - STITCHING MACHINE FOR SEWING WITH A SINGLE THREAD, ESPECIALLY FOR SEWING THE CLOSURE OF THE TOE OF STOCKINGS - Google Patents

Description

DESCRIPTION

The present invention relates to a sewing machine for the execution of seams with a single thread, particularly for the closing seam of the toe of socks.

Various sewing machines are known which use one or two threads for the execution of the stitches.

Sewing machines that use a single thread generally comprise a hook which is oscillated around an axis, and a needle which is operated with reciprocating motion along a direction perpendicular to the axis of the hook so as to cross the object to be sewn. The hook, with its oscillation, cyclically hooks the thread carried by the needle, forming a buttonhole that is crossed by the needle in a subsequent phase, thus forming the sewing chain.

In the sector of hosiery machines, in recent years, devices have been developed which are capable of transferring the stocking from the circular hosiery machine that produced it to a sewing head which closes the toe of the stocking.

One of these devices is the subject of patent application no. MI99A-001690 by the same Applicant, and substantially consists of a crown member which is positioned above and coaxially to the needle cylinder of a hosiery machine and which is provided with a plurality of radial hooks, which are operated so as to pick up the loops of the last row of stitch, formed by the needles of the needle cylinder, and to be transferred to the sewing head. The crown organ is divided into two halves that are superimposed on each other in such a way as to face the loops of the last rank that must be stitched. In practice, after the overturning, a hook or a pair of hooks of one half of the crown member carries two loops which must be mutually stitched, so as to close the toe of the stocking.

The operation of sewing the pairs of loops carried by the hooks of the crown member, carried out with sewing heads of a known type, has not given fully satisfactory results.

The aim of the present invention is to provide a sewing machine capable of fully satisfying the specific requirements inherent in the sewing operation for closing the toe of socks with the pairs of knitting loops, to be sewn together, carried by the hooks of a crown member used to remove the sock from the machine that produced it.

Within this aim, an object of the invention is to provide a sewing machine capable of closing the toe of socks by means of a seam that uses a single thread.

Another object of the invention is to provide a sewing machine which has high sewing precision and reliability.

This task, as well as these and other purposes which will become clearer hereinafter, are achieved by a sewing machine for the execution of seams with a single thread, particularly for the closing seam of the toe of socks, comprising a hook that can be oscillated around an axis. of the hook and a needle movable with reciprocating motion along an actuation direction oriented substantially perpendicular to said axis of the hook to cross the object being sewn, said hook, which is provided with a tip that can be inserted, in the oscillation of movement, of the hook, between one side of said needle and the branch of thread extending from the eye of the needle along said side for the formation, with said branch of thread, of a loop of thread around the trajectory of said needle, characterized by the fact that said hook has a substantially sickle-shaped conformation arranged in a plane substantially perpendicular to said axis of the hook and defined, in an intermediate area of its development, a passage oriented substantially radially with respect to said axis of the hook and which can be aligned with the trajectory of said needle following the oscillation of the hook around its axis; said passage being traversable by the needle and being able to allow the hook to disengage from the needle, inserted in said passage, in the return oscillation of the hook.

Further characteristics and advantages of the invention will become clearer from the description of a preferred but not exclusive embodiment of the machine according to the invention, illustrated, by way of non-limiting example, in the accompanying drawings, in which:

Figure 1 is a perspective view of the sewing machine according to the invention;

Figure 2 illustrates an enlarged detail of Figure 1;

Figure 3 shows the needle of the sewing machine in lateral elevation, partially sectioned;

Figure 4 schematically shows the machine according to the invention in front elevation, partially sectioned;

Figure 5 shows an enlarged detail of the machine according to the invention seen from the axis of the sewing needle;

Figures 6 to 22 schematically illustrate the sequence of operation of the machine according to the invention in the execution of the seam.

With reference to the aforementioned figures, the machine according to the invention, generally indicated by the reference number 1, comprises a hook 2 which can be oscillated around an axis of the hook 2a, and a needle 3 which is movable with reciprocating motion along a direction of drive 4 oriented substantially perpendicular to the axis of the hook 2a to cross the object being sewn.

The hook 2 is provided with a tip 5 which can be inserted, in the outward swing of the hook 2, between one side of the needle 3 and the branch of thread 6a, which extends from the eye 7 of the needle 3 along this side, to form, with this branch of thread 6a, a loop of thread around the trajectory of the needle 3.

According to the invention, the hook 2 has a substantially sickle-shaped conformation, arranged in a plane substantially perpendicular to the axis of the hook 2a, and with defined, in an intermediate zone of its development, a passage 8, oriented substantially radially with respect to the axis of the hook 2a and can be aligned with the path of the needle 3 following the oscillation of the hook 2, around its axis 2a. The passage B can be crossed by the needle 3 and is adapted to allow the disengagement of the hook 2 from the needle 3, inserted in the passage B, in the return oscillation of the hook 2.

More particularly, the hook 2 is substantially shaped like an arc of a circle centered on the axis 2a, and is fixed, at the opposite end with respect to its tip, to an arm 9 which extends radially and which is hinged to a structure support 10 around the axis 2a.

The passage B is defined between a side of the hook 2 and an elastically flexible sheet 11, which is connected to this side of the hook 2. The sheet 11 also has an arc-shaped conformation, and is superimposed on a side. of the hook 2. The end of the lamina 11 which faces the tip 5 of the hook rests by elasticity against the side of the hook 2, while the other end is fixed, for example by means of screws 12, to the hook 2.

The end of the lamina 11 facing the tip 5 of the hook 2 rests in a recess 13 specifically defined in the side of the hook 2. The lamina 11 is elastically flexible away from the side of the hook 2 to allow the looper 2 to disengage from the needle 3, inserted through passage 8, during the return swing of hook 2, as it will appear better later.

The needle 3 is provided, on its side which is intended to be turned towards the hook 2, with a lowered area 14 to facilitate the passage of the hook 2 between this side of the needle 3 and the branch of thread 6a which extends along that side.

The hook 2 has, in its portion which is comprised between the passage 8 and its tip 5, a shoulder 16 for retaining the loop of thread which is hooked by the hook 2.

This shoulder 16 is defined by a tooth 17 which extends from the side of the hook 2, facing the axis 2a, in the direction of the same axis 2a.

Advantageously, the sewing machine according to the invention is also provided with means for stretching the thread loop, hooked by the hook, 2, in the opposite direction with respect to the tip 5 of the hook 2.

These tensioning means comprise a tensioning member 18 which is arranged on the side of the hook 2 facing away from the axis of the hook 2a and which can be oscillated, with the direction of oscillation opposite to that of the hook 2, around the axis of the hook -2a, to engage with one of its ends with the two branches of the loop of thread, hooked by the hook 2, which come from the two opposite sides of the hook 2.

The tensioning member 18 is substantially constituted by a sheet curved according to an arc of circumference also having a center on the axis 2a and a radius slightly greater than the radius of the side of the hook facing away from the axis 2a, in in such a way that the oscillation, with opposite directions between them, of the hook and of the stretching member 18 around the axis 2a causes the passage of the stretching member 18 on the side of the hook 2 facing away from the axis 2a.

The end of the stretching member 18, which can be engaged with the two branches of the loop of thread hooked by the hook 2, has a pair of receptacles 19a and 19b intended to receive the two branches of the loop of thread.

Furthermore, starting from this end and for a portion of the arched extension of the stretching member 18, a slot 20 is provided to allow the oscillation movement of the stretching member 18 around the axis 2a despite the presence of the needle 3 inside step 8.

The stretching member 18 is fixed to an arm 21 which is hinged to the support structure 10 also around the axis 2a.

The needle 3 is mounted on a needle holder 22, which is supported, in a sliding manner parallel to the direction 4, by a portion of the support structure 10.

The needle holder member 22 is also hinged to the end of a lever 23, which is hinged, with an intermediate portion thereof, to the support structure 10 around an axis 24, parallel to the axis 2a.

The other end of the lever 23 is hinged to a rod 25 which connects the lever 23 to an eccentric pin 26 fixed to the end of a shaft 27.

The shaft 27 is connected, through a belt connection 28, to the output shaft of a motor 29, preferably constituted by an electric stepping motor, supported by the support structure 10.

Also fixed to the shaft 27 is a cam 30 against which a follower roller 31 is engaged, mounted on a slide 32, which is supported, in a sliding manner along a direction perpendicular to the axis 2a, by the support structure 10.

A pair of springs 33 acts on the slide 32 which have the function of maintaining contact between the cam follower roller 31 and the profile of the cam 30. The slide 32 is connected, by means of a first connecting rod 34 and a second connecting rod 35, respectively to the hook 2 and to the tensioning member 18. The two connecting rods 34 and 35 are hinged, with one of their ends, to the slide 32, in correspondence with the same jockeying axis 36. In practice, the translation of the slide 32 in approach or away-

movement to the axis of the hook 2a, deriving from the action of the cam 30 on the cam follower roller 31, causes the oscillation of the hook 2 and of the tensioning member 18 around the axis 2a, with opposite directions of oscillation.

The connection existing between the shaft 27 and the needle holder member 22, and between the shaft 27 itself and the hook 2 and the tensioning member 18, guarantees the synchronization of the movements of the needle 3, of the hook 2 and of the 'stringing organ 18.

The operation of the sewing machine according to the invention is as follows.

The object to be sewn, in particular a sock, is preferably arranged on the half of a crown member 40, for example of the type described in patent application no. MI99A-001690 by the same Applicant, between the needle 3, carried away from the hook 2 and the hook 2 itself. arranged on the same hook or on the same pair of hooks side by side, as already described in the aforementioned patent application.

Initially, the initial end of the thread used for sewing, passing through the eye 7 of the needle 3, is stapled in a per se known manner. At the beginning of the actuation of the needle 3, the hook 2 is with its tip 5 spaced laterally from the axis 4 of the needle 3. While the needle 3 begins its approach to the axis of the hook 2a, the hook 2 is oscillated forward in such a way as to move with the passage 8 in alignment with the axis of the needle 3, so that the needle 3, continuing in its motion in the direction of the axis of the hook 2a, crosses the passage 8 after passing through the two loops 51 to be sewn (figures 6 and 7).

Subsequently, the needle 3 is operated in the opposite direction, while the hook 2 returns to the initial condition (Figure 8). It should be noted that the oscillation in return of the hook 2 to return to the initial position can take place precisely due to the fact that the lamina 11 detaches itself elastically from the side of the hook 2 allowing it to disengage from the needle 3 while the latter is still inserted inside step 8.

Subsequently, the hook 2 is oscillated again outward, while the needle 3 is completing its return motion, so that the tip 5 of the hook 2, passing over the lowered area 14 of the side of the needle 3, hooks the branch 6a of the sewing thread which is on this side (figure 9).

The hook 2 then continues in its forward motion forming a loop of thread 41 which extends around the trajectory of the needle 3 (figures 10 and

It should be noted that, while the hook 2 continues in its forward oscillation, the tensioning member 18, not shown in figures 6 to 22, oscillates in the opposite direction, stretching the slot 41 in the opposite direction with respect to the tip 5 of hook 2. Buttonhole 41 is also hooked to notch 17 of hook 2.

When the needle 3 has finished its return motion, a new pair of loops 52 is positioned in correspondence with the axis of the needle 3 (Figure 12).

The needle 3 then begins again its movement towards the hook 2 by crossing this new pair of loops 52 and arriving in correspondence with the hook 2 while this is positioned with the passage 8 in alignment with the trajectory of the needle 3. In this way, the needle 3 passes through the slot 41 and passes through the passage 8 (figures 13 and 14). The hook 2 is then oscillated in return disengaging from the needle 3 while the excess thread is recovered in a per se known manner (Figure 15).

At this point of operation, the buttonhole 41 is crossed by the needle 3 and by the sewing thread which is carried by the same needle 3 (Figure 16).

The subsequent outward oscillation of the hook 2 causes the tip 5 of the hook 2 to engage the branch 6a of the thread and to form a new slot 42 while the needle 3 is extracted from the passage 8 (Figures 17 to 21).

After the needle 3 has finished its return motion and has moved externally to the slot 41, while the hook 2 has finished its outward oscillation by bringing the passage 8 back into alignment with the trajectory of the needle 3, the sock is moved again relative to the needle 3 in such a way as to bring a new pair of loops 53 to be subjected to sewing in correspondence with the trajectory of the needle 3 (Figure 22). The subsequent advancement motion of the needle 3 in the direction of the hook 2 brings the needle 3 to cross this new pair of loops 53 and to cross the passage 8, as already described.

At this point, the cycle continues as already described, forming a sewing chain that joins the various pairs of loops of the sock.

It should be noted that, thanks to the presence of the stretching member 18, it is possible to vary the direction of sewing, that is to say, to vary the direction of advancement of the object subjected to sewing relative to the needle, obtaining in any case a perfect sewing thanks to the intervention of the stretching member 18 which in any case maintains correctly positioned the loops of thread formed by the hook to be crossed by the needle in the formation of the chain.

This opportunity can be used advantageously at the beginning of the seam, starting the seam, instead of from one end of the object to be sewn, in correspondence with an internal area of the object and performing a seam section in the opposite direction with respect to the seam direction. which is performed only later by reversing the sewing direction again. Thanks to this expedient, the tail of the sewing thread can be trapped inside the sewing chain and therefore is practically invisible, making finishing operations unnecessary to proceed with the removal of the tail of the sewing thread.

In practice it has been found that the sewing machine according to the invention fully achieves the intended aim, since it is capable of sequentially sewing pairs of knitting loops which are carried by a crown or semi-crown member and is therefore particularly suitable to perform the closing seam of the toe of socks.

A further advantage of the sewing machine according to the invention is that of being able to sew indifferently with two opposite sewing directions.

The sewing machine according to the invention, although it has been conceived in particular to be used to perform the closing seam of the toe of stockings worn by a crown or semi-crown member of the type illustrated in the patent application MI99A-001690, can in any case be used. to sew socks mounted on other supports or other objects, as needed.

The sewing machine thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept; moreover, all the details can be replaced by other technically equivalent elements.

In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

Claims (12)

R IV E N D I C A Z I O N I 1. Sewing machine for the execution of seams with a single thread, particularly for the closing seam of the toe of socks, comprising a hook oscillating around an axis of the hook and a movable needle with reciprocating motion along a direction of actuation oriented substantially perpendicular to said axis of the hook to cross the object being sewn, said hook being provided with a tip which can be inserted, in the forward oscillation of the hook, between one side of said needle and the branch of thread extending from the eye of the long needle said side for the formation, with said branch of thread, of a loop of thread around the trajectory of said needle, characterized in that said hook has a substantially sickle-like conformation arranged in a plane substantially perpendicular to said axis of the hook and with , defined, in an intermediate zone of its extension, a passage oriented substantially radially with respect to said axis of the cro chet and can be aligned with the trajectory of said needle following the oscillation of the hook around its axis, - said passage being traversable by the needle and being able to allow the disengagement of the hook from the needle, inserted in said passage, in the oscillation return of the looper. 2. Sewing machine, according to claim 1, characterized in that said passage is defined between a side of the hook and an elastically flexible sheet fixed to said side of the hook, the portion of said sheet extending from said passage towards the tip of the hook being supported by elasticity against the side of the hook and being flexible in distance from the side of the hook to allow disengagement of the hook from the needle, inserted through said passage, in its return oscillation. 3. Sewing machine, according to claims 1 and 2, characterized in that the free end of said lamina, facing the tip of the hook, rests in a recess defined in the side of the hook. 4. Sewing machine, according to one or more of the preceding claims, characterized in that said side of the needle has a lowered area for the passage of the hook. 5. Sewing machine, according to one or more of the preceding claims, characterized in that said hook, in its portion comprised between said passage and the tip, has a shoulder for retaining the loop of thread hooked by the hook. 6. Sewing machine, according to one or more of the preceding claims, characterized in that said retention shoulder comprises a tooth extending on the side of the hook facing the axis of the hook. 7. Sewing machine, according to one or more of the preceding claims, characterized in that it comprises means for stretching the loop of thread, hooked by the hook, in the opposite direction to the tip of the hook. 8. Sewing machine, according to one or more of the preceding claims, characterized in that said stretching means comprise a stretching member arranged on the side of the hook facing the opposite side to the axis of the hook and oscillating, with opposite direction of oscillation with respect to that of the looper, around the axis of the looper to engage with one of its ends with the two branches of the loop of thread coming from the two opposite sides of the looper. 9. Sewing machine, according to one or more of the preceding claims, characterized by the fact that the end of the stringing member 'engaging with' two branches of the loop of thread has receptacles for said two branches of the loop of thread. 10. Sewing machine, according to one or more of the preceding claims, characterized in that said hook and said tensioning member are hinged to a support structure around said axis of the hook and are connected to a common actuation member translating perpendicularly to said axis of the hook for the simultaneous actuation of said tensioning member and of said hook with oscillatory motion around the axis of the hook with opposite directions of oscillation. 11. Sewing machine, according to one or more of the preceding claims, characterized in that said needle, said hook and said stretching member are kinematically connected to each other for the synchronization of their movements. 12. Sewing machine for the execution of seams with a single thread, particularly for the closing seam of the toe of socks, characterized in that it comprises one or more of the characteristics described and / or illustrated.