Patent Publication Number: US-8109220-B2

Title: Device and method to align the edge surrounding an end of a tubular knitted article

Description:
TECHNICAL FIELD 
     The present invention relates to a machine or device for handling tubular knitted articles, such as in particular—but not exclusively—stockings and socks. 
     More specifically, the present invention relates to a device useful for pre-paring tubular knitted articles of the aforesaid type—which are unloaded from the knitting machine in which they are produced with the toe open—for the subsequent operations to sew the toe. 
     STATE OF THE ART 
     WO-A-2005/100664 describes a complex machine, comprising a plurality of stations having the function of picking up the individual socks or other tubular knitted articles from a basket and preparing them for sewing in a sewing machine comprising a guillotine. One of these stations has the function of aligning approximately on a plane the edge or band surrounding one of the ends of the article and more specifically the edge surrounding the open toe thereof. This station comprises an operating head provided with a plurality of contact members, controlled in order to selectively move toward an article inserted on a tubular support and transport member. The relative movement between the tubular member, with the tubular article inserted thereon, and the contact members is such that contact between these members and the tubular article takes place in different times according to the position of the tubular knitted article on the tubular transport member. The tubular knitted article is made to slide on the tubular transport member by the pads which gradually come into contact therewith and press it on the surface or side wall of the tubular transport member. The final result of the operation is to align approximately on a plane orthogonal to the axis of the tubular transport member all the portions of the edge surrounding the open toe of the tubular knitted article, so that the entire band or edge surrounding the toe opening is approximately on the same plane substantially orthogonal to the axis of the tubular member. This facilitates the subsequent operations to pick up and insert the toe of the tubular knitted article in the sewing machine. 
     OBJECT AND SUMMARY OF THE INVENTION 
     According to a particular aspect, an object of the invention is to improve the device described above to make it faster and more reliable. 
     In substance, this and other objects and advantages, which will be clear to those skilled in the art from reading the text below, are obtained with a device of the type mentioned above, wherein the operating head comprises, besides the pads, at least one wheel or preferably a pair of wheels to act on the fabric of the tubular knitted article. These wheels, suitably motorized, perform the movement of the part of the fabric of the tubular knitted article, which at the beginning of the operating cycle is above the front end of the tubular transport member. In this way the step to unload the tubular knitted article from the front portion of the tubular transport member is accelerated, as is the subsequent alignment step through the movement of the pads, which come gradually, and selectively into contact with the textile material of the tubular knitted article inserted on the tubular member. 
     Further features and preferred embodiments of the invention will be described in greater detail below with reference to the drawings and are indicated in the appended claims, which form an integral part of the present description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood by following the description and accompanying drawing, which shows a practical non-limiting embodiment of the invention. More specifically, in the drawing: 
         FIG. 1  shows an overall side view of the device with the operating head and the tubular member with the tubular knitted article inserted thereon; 
         FIG. 1A  shows a section according to  1 A- 1 A in  FIG. 1 ; 
         FIG. 2  shows a view analogous to  FIG. 1  in the first operating step; 
         FIGS. 3A ,  3 B and  3 C shows subsequent operating steps of a possible work cycle; 
         FIGS. 4 and 5  show a further two operating steps of a possible operating cycle. 
     
    
    
     DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION 
     The device comprises an operating head  1432  which cooperates with a tubular member  377 , on which the tubular knitted article is disposed, for example to transport it through subsequent stations of a same machine. In the embodiment shown the arrangement of the tubular transport member  337  is vertical, but it must be understood that the orientation of the entire machinery can be rotated, i.e. placing the tubular transport member  337  with the axis thereof horizontal or even with an intermediate inclination. 
     According to a possible embodiment, the station  1432  comprises a plate  1435  facing a front end of the tubular member  337 . The plate  1435  and the tubular member  337  are movable with respect to each other according to the double arrow f 1435  to move reciprocally toward or away from each other. Advantageously, the operating head  1432  is movable in a direction substantially parallel to the axis of the tubular member  337 , while the tubular member is fixed or is provided with a movement orthogonal to the axis thereof to transfer the tubular knitted article from one station to the other of the machine. According to a possible embodiment an actuator  1437  is provided to impart the movement to said plate  1435 . In the embodiment shown a piston-cylinder  1437  is provided, but other embodiments are possible, including one with a electric stepper motor and a threaded bar engaging in a female screw, or other type of actuators. 
     According to an advantageous embodiment, a bracket  1439  connected rigidly to the plate  1435  supports an oscillating lever  1441 , hinged in  1443  to the bracket  1439 . An actuator  1445  controls the oscillating movement of the lever  1441 . At an end thereof, the lever  1441  supports a first wheel  1447 , the rotation of which is controlled by an electric motor (not shown) or by another suitable source of motion. 
     The oscillating lever  1441  supports an oscillating bracket  1449  hinged to the lever  1441  coaxially to the wheel  1447 . An actuator  1451  controls the oscillating movement of the oscillating bracket  1449  around the axis of oscillation thereof. The oscillating bracket  1449  supports a second wheel  1453 , which is connected to the wheel  1447  through a motion transmission belt  1455 , so that this motor (not shown) will make both the wheels  1447 ,  1453  rotate. It would also be possible to provide a second separate motor for the wheel  1453 , although the arrangement shown is preferred as it requires a more limited number of mechanical parts. 
     According to a possible embodiment the plate  1435  supports an additional actuator  1461  connected to a supporting member  1463  disposed below the plate  1435 . A plurality of brackets  1465  are rigidly connected and extend below the supporting member  1463 . In a possible embodiment three of these brackets  1465  are provided, spaced from one another by 90° (see  FIG. 1A ) about the axis Ax-Ax of the device. In an advantageous embodiment, each bracket  1465  is provided with a movable pad  1467 . Each pad  1467  is movable in a radial direction, i.e. substantially orthogonal to the axis Ax-Ax, and the movement thereof is controlled by actuators  1469 . 
     In an advantageous embodiment, tabs  225  are provided housed inside the tubular member  337 , extractable and retractable through slots provided in the cylindrical side wall of this tubular member. The tabs and the slots extend in a direction substantially parallel to the axis of the tubular member. In a preferred embodiment the tabs  225  are provided with slots or longitudinal slotted openings indicated with  225 X. 
     The wheels  1447 ,  1453  and each pad  1467  are provided with respective sensors which, in a preferred embodiment, comprise an optical emitter and an optical receiver, indicated with  1471  and  1473  and arranged one in front of the other so that a beam of light passes through the slots  225 X at least during a part of the operating cycle, as will be described better in greater detail below. 
     The device  1432  operates as follows: in  FIG. 1  the tubular member  377  and the tubular knitted article M are taken into alignment with the plate  1435  of the device  1432 . The toe of the article M partially covers the upper edge of the tubular member  377  and the plate  1435  is arranged at a distance with respect to the tubular member  377 , so that the pads  1467  and the wheels  1447  and  1453  are not touching the tubular member  377  and the article M disposed thereon. 
     In the subsequent step ( FIG. 2 ), the actuator  1437  lowers the plate  1435  and the oscillating lever  1441  is made to oscillate counter-clockwise until the wheel  1447  is pressing against the upper edge of the tubular member  377 . The oscillating bracket  1449  is also moved to press the wheel  1453  against the side surface of the tubular member  377 . In a preferred embodiment in this step the tabs  225  are retracted inside the tubular member  377 , i.e. they are not projecting from the cylindrical side surface of the tubular member  377 . 
     The wheels  1447 ,  1453  are made to rotate until the fabric of the toe of the article M has been fully removed from the edge of the tubular member  377  and made to slide along the cylindrical side surface thereof for a certain length (see  FIG. 3A ). In a possible operating mode, at this point the tabs  225  are partially extracted and the direction of rotation of the wheels is reversed, so that the portion of fabric engaged by the wheel  1453  is moved slightly toward the upper edge of the tubular member  377 . This movement is halted as soon as the sensor  1471  detects the edge or band F of the toe P of the tubular knitted article M through the slotted hole  225 X produced inside the corresponding tab  225 . The final position is shown in  FIG. 3B . In the absence of slotted holes  225 X the optical sensors can be arranged so that they detect the thickness of the fabric on the longitudinal edge of the tabs  225 . 
     The remaining part of the band or edge F is normally in a lower position not known in advance. The object of the subsequent steps of the operating cycle is to align the entire band F of the toe at approximately the same height, i.e. approximately on a plane substantially orthogonal to the axis of the tubular member  377 . 
     To attain this object, according to a preferred embodiment of the invention, the supporting member  1463  is gradually moved toward the tubular member  377 . Each pad  1467  is thus lowered ( FIG. 3C ). As soon as the corresponding sensor  1473  detects the edge or band F surrounding the toe of the tubular knitted article M, the corresponding actuator  1469  pushes the pad against the tubular member  377  or preferably against the radially projecting longitudinal edge of the respective partially extracted tab  225 . Detection is facilitated by the slots  225 X, as the beam of light of the sensors passes through said slots  225 X and is interrupted as soon as the beam encounters the fabric. The same operating mode is provided for the sensor  1471 . 
     Subsequently, the movement of the supporting member  1463  is preferably continued for a certain length after each pad  1467  has been moved against the tubular member  377  or the tab  225 . Once the pad  1467  has been moved to press against the edge of the corresponding tab  225 , it draws the fabric along the edge of this tab until the supporting member  1463  is halted. Consequently, as all the sensors  1473  are disposed in the same position with respect to the corresponding pad  1467 , at the end of the downward travel of the supporting member  1463  the portions of fabric in contact with the pads  1467  are all at the same height with respect to the upper edge of the tubular member  377 , as shown in  FIG. 4 . 
     According to a preferred embodiment of the invention, the movement of the supporting member  1463  is then reversed until the pads  1467  have taken the fabric to the same height with respect to the portion of fabric engaged by the wheel  1453 . The final result of this operation is shown in  FIG. 5 : the band or edge F of the toe P of the tubular knitted article M is approximately aligned along a plane parallel to the upper edge of the tubular member  377 . 
     It must be understood that slightly different operating sequences from those described can be utilized to obtain the final result of alignment of the edge F of the tubular knitted article M. However, in general the device will perform a first step to unload the pocket of fabric of the toe from the portion or front end of the tubular member  377  through the wheels  1447 ,  1453 , this operation being performed by a reciprocal movement between operating head  1432  and tubular member  1437  along the direction parallel to the axis of this tubular member, in combination with the substantially radial movement of the pads  1467  controlled selectively by means of signals generated by the sensors  1473 . Closing and sliding of the pads on the tubular member  377  ultimately takes the edge F of the toe P to an alignment at the desired height. 
     It is understood that the drawing only shows an embodiment of the invention, which can vary in forms and arrangements without however departing from the scope of the concept underlying the invention. Any reference numerals in the appended claims are provided to facilitate reading of the claims with reference to the description and to the drawing, and do not limit the scope of protection represented by the claims.