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The present invention relates to a sewing machine and crochet device thereof.

More specifically, the invention concerns a sewing machine equipped with a set of crochet devices, adapted to cooperate with as many needle devices, in order to realize seams in desired configurations on a textile support.

Sewing machines are known that are constituted, among other thinks, by a pivoting shaft on which a number of crochet members are mounted, in a fixed way, with a portion shaped like a hook that oscillates integral with the shaft.

These machines also comprise needle members, corresponding, in number, to that of the crochet members and bearing the threads needed to carry out the seams desired.

The above mentioned needle members, moving with a vertical reciprocating motion, cooperate with the hooks of the underlying crochet members, so as to form a series of seams on a textile support.

Some of the sewing machines of known type also provide the possibility of deactivating one or more needle members, so that only a part of them interact with the corresponding crochet members, oscillating about their own shaft.

Therefore, also in these "improved" sewing machines, all the crochet members is set in motion, or in oscillation, even if not all of them cooperate for the seam of the working textile support.

Known type sewing machines have, however, several drawbacks and disadvantages.

The continuous movement of the crochet members determines, in fact, wear problems and the appearance of frequent breakdowns and malfunctions, which could lead to long and frequent periods of inactivity, and therefore unproductiveness, of the machine.

Therefore, the known sewing machines have generally fairly high operating costs, due mainly to the need to perform extraordinary maintenance operations with a certain frequency.

In light of the above, it is, therefore, object of the present invention to provide a sewing machine that is reliable in operation and such as to require reduced operating costs.

A further object of the invention is to provide a sewing machine configured so as not to require the disconnection of the thread from the corresponding hook device, when the latter does not contribute to the seam of the textile support in process, so as to reduce the downtimes and to maximize the productivity of the machine itself.

Another object of the invention is to provide a sewing machine which allows obtaining stitched textile supports of pleasant appearance and substantially free of aesthetic imperfections.

Another object of the invention is to provide a sewing machine functioning so as to result in a small number of extraordinary maintenance.

Further object of the present invention is to provide a sewing machine of simple manufacture and which is capable of ensuring high machining speeds.

It is therefore specific object of the present invention a machine for sewing textile products (4), comprising a frame, at least one shaft, rotatably engaged with said frame about a rotating axis, motor means, connected with said at least one shaft to make said at least one shaft oscillate about said rotating axis, at least one crochet device, comprising a support, where a through hole is formed, in which said at least one shaft is idly arranged, a hook, connected with said support, and coupling means, for selectively coupling said support to said at least one shaft, at least one needle device, adapted to cooperate with a crochet device to perform at least one seam in a textile product.

Still according to the invention, said at least one shaft could have an outer surface in which at least one cavity is formed and in that said coupling means comprise a first pin being movable between an operative position, where said first pin interferes with said at least one cavity, and a neutral position, where said first pin does not interfere with said at least one cavity.

Preferably according to the invention, said at least one crochet device could comprise a first guide element for guiding movement of said first pin; said first guide element being provided with a first through hole wherein said fist pin is arranged.

Further according to the invention, said at least one crochet device could comprise a first ring seal arranged in said first guide element for seal between said first pin and said first guide element. Still according to the invention, said at least one crochet device could comprise an enlarged portion connected with said first pin and in that a first variable volume chamber, in communication with said enlarged portion, and a first passage, in communication with said first chamber are defined in said support.

Always according to the invention, a second variable volume chamber, in communication with said enlarged portion and arranged opposite said first chamber with respect to said enlarged portion (16a), and a second passage, in communication with said second chamber, are defined in said support.

Advantageously according to the invention, said at least one crochet device could comprise a second ring seal arranged around said enlarged portion for seal with said support.

Still according to the invention, said sewing machine could comprise an alignment plate fixed to said frame, at least one alignment cavity being formed in said alignment plate, and in that said at least one crochet device comprises a second pin connected to said enlarged portion and directed in a direction opposite to said first pin, such that, when said first pin is in said operative position, said second pin does not interfere with said alignment cavity, instead, when said first pin is in said neutral position, said second pin interferes with said alignment cavity, causing block of said at least one crochet device.

Preferably according to the invention, said at least one crochet device could comprise a second guide element for guiding movement of said second pin; said second guide element being provided with a second through hole wherein said second pin is arranged.

Further according to the invention, said at least one crochet device could comprise a third ring seal arranged in said second guide element for seal between said second pin and said second guide element.

Still according to the invention, said sewing machine could comprise at least one bearing arranged between said at least one shaft and said at least one crochet device.

Advantageously according to the invention, said machine could comprise a cutting device for each of said at least one crochet device, said cutting device being configured to cut a thread which is connected with said at least one crochet device, when in use, substantially next to said textile product. It is object of the present invention also a crochet device comprising a support, where a through hole is formed, a hook, connected with said support, and an activation member, comprising an enlarged portion, a first pin and a second pin; said first pin and said second pin being directed in substantially opposite directions with respect to said enlarged portion, wherein a first variable volume chamber in communication with said enlarged portion, a second variable volume chamber which is in communication with said enlarged portion and arranged opposite said first chamber with respect to said enlarged portion, a first passage which is in communication with said first chamber, and a second passage which is in communication with said second chamber.

The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiments, with particular reference to the figures of the enclosed drawings, wherein:

figure 1 shows an overall view of a sewing machine according to the present invention, with a zoom on a portion of said machine;

figure 2 is a perspective view of a plurality of functional groups of the sewing machine shown in figure 1 ;

figure 3 is a further view of the functional groups shown in figure 2, in which also another component of the machine interacting with said functional groups appears;

figure 4 is a perspective view of a crochet device according to the present invention;

figure 5 is a sectional view of the crochet device shown in figure 4; figure 6 is a perspective view of a crochet device, mounted on a respective shaft, and an auxiliary cutting device to cut the thread used by this device crochet device; and

figure 7 is a side view of the crochet device and of the auxiliary cutting device shown in figure 6.

In the various figures, similar parts will be indicated by the same reference numbers.

Referring to the enclosed figures, by the reference number 1 it is indicated a sewing machine, comprising a frame 2 conformed to be placed on the ground.

An opening 3 is obtained on the frame 2 for the passage of a textile support, i.e. a textile product 4 to be worked.

The textile product 4 is advanced through the action operated by a rotating roller 2' arranged in correspondence with said opening 3.

Below said opening 3 a crochet operating unit 5 is arranged, made by three functional groups 6 equal to each other.

Each functional group 6 comprises a shaft 7, which is arranged substantially horizontally, rotatably constrained to the frame 2, and a plurality crochet devices 8 mounted on said shaft 7.

The shaft 7 is connected to motor means (not shown in the figures), capable to set it into oscillation around its symmetry axis 7', as indicated with the double arrows F in figures 1 and 2.

On the outer surface of the shaft 7 a plurality of connecting cavities arranged aligned in the longitudinal direction of said shaft 7 is formed, in correspondence of said crochet devices 8.

Each crochet device 8 comprises a support 9 on which is fixed above a hook 10 for seam operations.

In the support 9 is moreover obtained a through hole 11 , through which said shaft 7 passes.

The shaft 7 and each crochet device 8 are mutually connected by two bearings 12 (only one of which can be seen in the enclosed figures), arranged at two opposite edges of the through hole 11 of said support 9.

In support 9 a cavity 13 is internally defined communicating with the through hole 11 and in which two guide elements 14a, 14b are arranged, fixed and opposing.

Said guide elements 14a, 14b have, respectively, two through holes mutually coaxial and just as many O-rings, or ring gaskets 15a, 15b arranged in correspondence with said two through holes.

Each crochet device 8 also comprises an activation member 16, arranged in the cavity 13 and movable in translation between an operating position, in which said crochet device 8 is rigidly engaged to said shaft 7, and a neutral position, in which said crochet device 8 and said shaft 7 can move relative to one another, being mutually decoupled.

Said activation member 16 is formed by a central enlarged portion 16a, from which extend, in opposite direction, a first upper pin 16b, and a second lower pin 16c, mutually coaxial.

On the outer edge of said enlarged portion 16a a circumferential groove is formed, which is suitable to house an O-ring, i.e. a sealing ring 17, for sealing with the support 9.

The first pin 16b and the second pin 16c are, respectively, enabled to slide within the two through holes formed in the two guide elements 14a, 14b, in conditions of sealing, due to the action of the two sealing ring gaskets 15a, 15b.

The enlarged portion 16a of the activation member 16 is arranged between the two guide elements 14a, 14b, so as to define with them a first upper chamber 18a and a second lower chamber 18b, both of variable volume and of annular shape.

On an outer wall of the support 9 two passages are provided, namely two fluid communication ways 19a, 19b, respectively, communicating with the two chambers 18a, 18b and with a pneumatic system (not shown in the figures) by means of two connectors 20a, 20b and further connecting means of the known type.

The sewing machine 1 also comprises an alignment plate 21 fixed to the frame 2 and arranged below the crochet operating unit 5.

The upper surface of said alignment plate 21 has a plurality of alignment cavities 22 each arranged in correspondence of a crochet device 8, and precisely directly below the second pin 16c of the activation member 16, when said crochet device 8 is arranged in the vertical position shown in figure 3.

Above said opening 3 a needle operating unit is arranged, made by a plurality of needle members, connected to actuating means capable of making them move in a vertical alternative motion, so that said needle member can interact and cooperate with the underlying crochet devices 8 for sewing the textile support 4.

The sewing machine 1 also comprises a plurality of auxiliary cutting devices 23 (one of which is shown in figures 6 and 7) to cut the thread sections protruding from the textile supports at the end of the sewing operations, so that said stitched textile supports have a smooth overall appearance, and thus aesthetically pleasing.

In particular, downstream of each of the crochet devices 8 and of the above mentioned needle members, an auxiliary cutting device 23 is arranged, to cut both the threads connected to the needle members, and those used by crochet devices 8.

Each auxiliary cutting device 23 essentially comprises a support 24 with a linear guide 25, which is enabled to move a cutting member 26 provided, at one of its ends, with a blade 27 and actuated by a pneumatic cylinder-piston 28. The operation of the sewing machine 1 described above is as follows.

For simplicity of exposition, and considering that the crochet devices 8 operate all in the same way, though independently of each other, hereinafter it will be proceeded describing the operation of a single crochet device 8.

When air is channeled into the second chamber 18b of a device crochet 8, by means of the above mentioned pneumatic system, the corresponding activation member 16 moves upward due to the expansion of the air in said second chamber 18b, thus determining the insertion of the first pin 16b in a corresponding cavity of the upper connection of the shaft 7 and, consequently, the rigid connection of the crochet device 8 to the shaft 7.

This crochet device 8 moves, therefore, integrally with the shaft 7 on which is mounted, also this oscillating about the respective axis T.

In this case, the bearings 12 interposed between the crochet device 8 and the shaft 7 do not operate, they remain substantially stationary.

When, instead, air is channeled into the first chamber 18a of said crochet device 8, always by said pneumatic system, the activation member 16 moves downward due to the expansion of the air within said first chamber 18a, thus determining the disengagement of the first upper pin 16b from the corresponding connection cavity of the shaft 7 and, simultaneously, the insertion of the second lower pin 16c in the underlying alignment cavity 22.

In this way, said crochet device 8 remains stationary, while the shaft 7 that passes through it continues to move, by oscillating about its symmetry axis T and making, then, "operate", i.e. moving, the two bearings 12.

At the end of sewing operations come into operation the auxiliary cutting devices 23 which, nearing the corresponding blade 27 to each one of the above needle members and crochet devices 8, provide a clipped cutting of the seam thread to the textile support 4.

The present invention therefore allows to activate and to deactivate the individual crochet devices 8 independently of one another, so that only those activated, i.e. those whose respective activation member 16 interferes with the shaft 7, interact with the corresponding needle members of said needle operating unit. Therefore, by suitably varying the configuration of the active crochet devices 8 and the inactive ones, i.e. motionless, in the crochet operating unit 5, realizing seams in different areas of the textile support 4 is possible, while said textile support 4 passes through the opening 3 of the sewing machine 1.

According to further variants of the invention, not shown in the enclosed figures, the sewing machine 1 may include any number of functional groups 6.

The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that modifications and/or changes can be introduced by those skilled in the art without departing from the relevant scope as defined in the enclosed claims.