STRAIGHT LINKING MACHINE FOR KNITTED ARTICLES, WITH HIGHLY VERSATILE USE Technical Field

The present invention relates to a straight linking machine for knitted articles, with highly versatile use. Background Art

As is known, linking allows to join knitted articles with extreme precision, leading to a result which is fully satisfactory from an aesthetic standpoint, since the seam is practically invisible. Joining knitted articles by linking in fact consists in joining together two portions of knitting by means of a linking chain-stitch, which connects one another each loop of knitting of one portion of knitting to a corresponding loop of knitting of the other portion of knitting.

To perform this operation, circular linking machines and straight linking machines are currently commercially available.

Circular linking machines are composed substantially of a supporting structure which supports an annular comb provided with a plurality of radial prongs, which are regularly mutually spaced around the axis of the comb with a preset pitch and are adapted to support the knitted articles to be linked. At a region of the annular comb, the supporting structure supports a linking head, which is provided with linking elements constituted generally by a needle with an eye and by a looper or by a hook-shaped needle and a thread loading tube, which can be actuated so as to cooperate with each other to form the linking chain-stitch. This type of machine is actuated by a single motor, which is kinematically connected both to the annular comb and to the linking elements so as to produce a rotation of the annular comb about its own axis in order to position in each instance a prong at the linking elements and activate the linking elements so as to cyclically cause the insertion of the needle within a prong and its extraction, as well as the actuation of the looper or thread loading tube in order to allow, in

combination with the movement of the needle, to form the linking chain- stitch. Generally, in such machines, the needle and the looper or thread loading tube can move rigidly with the comb, while the needle engages a prong, so as to allow actuation with a continuous rotary motion of the comb. Straight linking machines are composed substantially of a supporting structure, which supports a linking head provided with linking elements in a manner similar to circular linking machines, and a straight comb which can move on command along an advancement direction with respect to the linking head. The comb is provided with a plurality of prongs, which are arranged mutually side-by-side along an advancement direction, are mutually spaced according to a preset pitch, and are adapted to support the knitted articles to be linked. Conventional straight linking machines also are actuated by means of a single main motor, which is connected kinematically both to the comb and to the linking elements so as to produce, in a synchronized manner, the advancement of the comb along the advancement direction in order to position, in each instance, a prong at the needle and actuate the needle so that it enters the prong arranged thereat and the looper or thread loading tube to form the linking chain-stitch.

The knitted articles to be linked are loaded, generally by hand, onto the comb by fitting, loop by loop, the two flaps to be joined of the knitted articles on the prongs of the comb.

The spacing pitch of the prongs of the comb corresponds to the gauge of the knitted articles to be linked.

Owing to the fact that currently commercially available linking machines cannot work with combs with different prong spacing pitches unless an economically inconvenient replacement is performed of most of the elements that compose the kinematic chains for connecting the linking elements and the comb to the main motor, a linking machine can be used exclusively to link knitted articles having a given gauge. As a consequence of this fact, companies that manufacture knitted

articles, in order to link articles with different gauges, must have a number of linking machines, one for each gauge. This need requires investments which can be excessive if production is fragmented and highly diversified in terms of gauge. For this reason, the need is particularly felt in the field to be able to have a linking machine which can be used for a plurality of gauges. Disclosure of the Invention

The aim of the present invention is to meet this need by providing a straight linking machine which can link knitted articles of different gauges. Within this aim, an object of the invention is to provide a structurally simple machine which can be manufactured at competitive costs.

Another object of the invention is to provide a straight linking machine which ensures high reliability in operation.

This aim and these and other objects, which will become better apparent hereinafter, are achieved by a straight linking machine for knitted articles, comprising a supporting structure which supports a linking head provided with linking elements and a comb which can move on command along an advancement direction with respect to said linking head, said comb being provided with a plurality of prongs, which are arranged side-by-side along said advancement direction, are mutually spaced according to a preset pitch and are adapted to support the knitted articles to be linked, said comb being movable along said advancement direction in order to position in each instance a prong at said linking elements which can be actuated according to a linking cycle in order to engage in each instance one of said prongs and disengage from said prongs in order to allow the movement of said comb along said advancement direction with respect to said linking elements, characterized in that it comprises first means for actuating said linking elements and second means for actuating said comb for its movement along said advancement direction, said first actuation means being functionally connected to said second actuation means to coordinate the advancement of

said comb along said advancement direction with the actuation of said linking elements, said first actuation means and/or said second actuation means being adapted to vary the extent of the advancement of said comb with respect to said linking elements during the period of disengagement of said linking elements from said prongs, as a function of the spacing pitch of said prongs of the comb. Brief Description of the Drawings

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

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

Figure 2 is a schematic front elevation view of the machine according to the invention;

Figure 3 is a schematic rear elevation view of the machine according to the invention;

Figure 4 is a top plan view of the machine according to the invention;

Figure 5 is an enlarged-scale sectional view of Figure 4, taken along the line V-V;

Figure 6 is a perspective view of the linking elements and of the corresponding actuation means. Ways of carrying out the Invention

With reference to the figures, the machine according to the invention, generally designated by the reference numeral 1, comprises a supporting structure 2 which supports a linking head 3 provided with linking elements

4 and a comb 5 which can move on command along an advancement direction, indicated by the arrow 6, with respect to the linking head 3.

The comb 5 is provided with a plurality of prongs 7, which are arranged mutually side-by-side along the advancement direction 6, are

mutually spaced according to a preset pitch, and are adapted to support the knitted articles to be linked.

The comb 5 can move along the advancement direction 6 in order to position, in each instance, a prong 7 at the linking elements 4, which can be actuated according to a linking cycle so as to engage, in each instance, the prong 7 that is arranged at them and disengage from the prongs 7 in order to allow the movement of the comb 5 along the advancement direction 6.

According to the invention, the machine comprises first means 8 for actuating the linking elements 4 and second means 9 for actuating the comb 5 in order to move it along the advancement direction 6. The first actuation means 8 are functionally connected to the second actuation means 9 to coordinate the advancement of the comb 5 along the advancement direction 6 with the actuation of the linking elements 4. The first actuation means 8 and/or the second actuation means 9 are adapted to vary the extent of the advancement of the comb 5 with respect to the linking elements 4 during the period of disengagement of the linking elements 4 from the prongs 7, as a function of the spacing pitch of the prongs 7 of the comb 5.

Preferably, the linking elements 4 are arranged in a fixed position with respect to the supporting structure 2 and the comb 5 is actuated with an intermittent motion along the advancement direction 6 so as to position in each instance a prong 7 at the linking elements 4.

More particularly, in the illustrated embodiment, the linking elements 4 comprise a needle 10 with an eye which is connected to a corresponding needle bar 1 1 which is supported, so that it can slide along a direction which is substantially parallel to the axis of the needle 10, by a supporting block 12, which is fixed to the supporting structure 2. The linking elements 4 comprise a looper or crochet hook 13, connected to a corresponding looper bar 14, which is supported, so that it can rotate about its own axis and slide along said axis, by an arm 15 which is also fixed to the supporting structure 2 and protrudes above the supporting block 12 so as to support the looper 13

in a position which faces the needle 10.

As an alternative, the linking elements can be constituted by a hook- shaped needle as a replacement of the needle 10 with an eye and a thread loading tube as a replacement of the looper 13. The first actuation means 8 comprise a first electric motor 20, the output shaft whereof is connected, by means of a toothed belt 21 , to a main shaft 22, which is connected kinematically, by way of corresponding toothed belts 23, 24, respectively to a lower shaft 25, which is supported so that it can rotate about its own axis by the supporting block 12, and to a first upper shaft 26, which is supported, so that it can rotate about its own axis, by the arm 15. The lower shaft 25 is connected, by way of known types of kinematic systems, such as for example an eccentric element 27 and a linkage 28, to the needle bar 11, so as to cause, as a consequence of the rotation of the lower shaft 25, the actuation of the needle 10 with a reciprocating motion along its own axis.

The first upper shaft 26 is connected, by means of an additional toothed belt 29, to a second upper shaft 30, which also is supported, so that it can rotate about its own axis, which is parallel to the axis of the first upper shaft 26, by the arm 15. The second upper shaft 30 is connected, by way of known types of kinematic systems, such as for example an eccentric element 31 with a corresponding linkage 32 and a cam 33, to the looper bar 14 so as to cause, as a consequence of the rotation of the second upper shaft 30, the translational motion of the looper 13 along the axis of the looper bar 14 and its oscillation about the axis of the looper bar 14. In practice, the actuation of the first electric motor 20 produces the actuation of the needle 10 with a reciprocating motion along its own axis and the oscillation and lifting and lowering of the looper 13 to form the linking chain-stitch.

The second actuation means 9 comprise a second electric motor 34, the output shaft of which is connected, by means of a toothed belt 35, to a

first pulley 36, which is supported, so that it can rotate about its own axis, which is oriented at right angles to the advancement direction 6, by the supporting structure 2.

The first pulley 36 is connected, by means of a toothed belt 38, to a second pulley 37, which is supported, so that it can rotate about its own axis, which is oriented parallel to the axis of the first pulley 36, by the supporting structure 2.

The upper arm of the toothed belt 38, which passes through the region occupied by the linking head 3, is fixed, by means of a block 39, to a slider 40, which can slide along a guide 41 which is fixed to the supporting structure 2 and is oriented parallel to the advancement direction 6. Two blocks 42a, 42b are provided on the slider 40 and the comb 5 can engage them detachably.

In practice, the actuation of the second electric motor 34, with an intermittent rotary motion about its own axis, causes the intermittent advancement of the slider 40, and consequently of the comb 5 mounted thereon, along the advancement direction 6. The comb 5 is arranged on the slider 40 so that during the advancement of said slider along the advancement direction 6 the comb 5 passes between the needle 10 and the looper 13, arranging cyclically one prong in alignment with the needle 10.

The prongs 7 can be constituted by known types of prongs which are contoured so as to support loops of knitting and be partially crossed by the needle 10 in a manner similar to the prongs of linking machines of a traditional type. At least one of the electric motors 20 and 34 is constituted by a variable-speed motor so as to allow to vary the extent of the advancement of the comb 5 along the advancement direction 6, while the needle 10 is disengaged from the prongs 7, as a function of the spacing pitch of the prongs 7. This possibility allows to use combs 5 with different spacing pitches of the prongs 7 and therefore to link knitted articles of different

gauges.

Preferably, the variable-speed electric motor is constituted by the second electric motor 34.

Preferably, said variable-speed electric motor is constituted by an electric step motor.

At least the variable-speed electric motor is connected to an actuation and control element 50 of the programmable electronic type, which is adapted to drive said electric motor according to programs which are preset as a function of the spacing pitch of the prongs 7 of the comb 5, i.e., of the gauge of the knitted articles to be linked.

Moreover, the first electric motor 20 and the second electric motor 34 are conveniently connected to the same actuation and control element 50, as shown, or to another actuation and control element of the electronic type, by means of which the actuation of the two electric motors 20 and 34 is coordinated so that the insertion of the needle 10 within a prong 7 of the comb 5 occurs when said prong 7 is arranged at the needle 10 and the advancement of the comb 5 along the advancement direction 6 is produced when the needle 10 is disengaged from the prongs 7 of the comb 5.

Operation of the linking machine according to the invention is as follows.

With the comb 5 arranged laterally to the linking head 3, as shown for example in Figure 1 , the flaps of the knitted articles to be linked are fitted, loop by loop, on the prongs 7 of the comb 5.

The first electric motor 20 and the second electric motor 34 are then actuated so as to actuate the linking elements 4 in order to form the linking chain-stitch and produce the advancement, with an intermittent motion, of the comb 5 along the advancement direction 6.

By way of this intermittent motion, the comb 5 is positioned in each instance with a prong 7 aligned with the needle 10, which by following its operating cycle partially enters said prong 7, passing through the loops of

knitting fitted thereon.

Subsequently, the needle 10 is extracted from the prong 7 and the comb 5 is made to advance by one pitch so as to place the following prong 7 at the needle 10, which by following its actuation cycle penetrates through said prong 7, passing through the loops of knitting supported thereby.

During the cycle for actuation of the needle 10 with a reciprocating motion along its own axis, the looper 13 cooperates with the needle 10 in forming the linking chain-stitch.

The machine according to the invention is capable of working with combs 5 of different gauges, i.e., with combs in which the spacing pitch between the prongs 7 is different.

The extent of the advancement of the comb 5 along the advancement direction 6 with respect to the linking elements 4, while the needle 10 is disengaged from the prongs 7, can in fact be changed so as to adapt it to the spacing pitch of the prongs 7.

This is preferably achieved by varying the advancement speed of the comb 5 by varying the actuation speed of the second electric motor 34 and keeping constant the actuation speed of the first electric motor 20 and thus keeping constant the actuation frequency of the needle 10 and of the looper 13. Substantially, by using combs with a high gauge, the advancement speed of the comb 5 along the advancement direction 6 is reduced, whereas with lower-gauge combs the advancement speed of the comb 5 along the advancement direction 6 is increased.

As an alternative, it is possible to keep constant the advancement speed of the comb 5 along the advancement direction 6 and vary, by varying the actuation speed of the first electric motor 20, the extent of the time interval during which the needle 10 is disengaged from the prongs 7.

In this manner, simply by replacing the comb 5, the linking machine according to the invention is capable of linking knitted articles of different gauges.

At the end of the linking process, the slider 40 is returned to the initial position by actuating in the opposite direction the second electric motor 34, while the needle 10 is kept disengaged from the prongs 7.

In practice it has been found that the linking machine according to the invention fully achieves the intended aim, since by being able to work with combs with different gauges it can link knitted articles of different gauges.

The machine thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

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

The disclosures in Italian Patent Application no. MI2007A001743, from which this application claims priority, are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.