"Method and device for pneumatically spreading an elongated flexible article, such as a stocking or a sock"

DESCRIPTION Technical Field The present invention relates to improvements to devices for handling flexible and elongated finished or semi-finished articles, for example and in particular, but not exclusively, stockings and socks or other textile articles. State of the Art

In the manufacture of knitted articles such as stockings or socks there is frequently the need to flatten, i.e. spread the article, which by nature is flexible and foldable, in order to prepare it for subsequent handling operations, such as sewing the toe of the article.

Spreading of the article must in general be performed both in a longitudinal and transverse direction, to flatten the semi-finished article and allow easy handling in the subsequent steps. Objects and Summary of the Invention

An object of the present invention is to provide a device that facilitates spreading, i.e. flattening of an article of the aforesaid type, in particular in a longitudinal direction but possibly also at least partly in a transverse direction with respect to the longitudinal extension thereof.

This and other objects and advantages, which shall be apparent to those skilled in the art by reading the text hereunder, are obtained in substance with a device comprising: a suction duct with a first end and a second end; a retaining member to hold a flexible article at least partly inserted in said suction duct; and a suction opening that puts the inside of the suction duct in communication with the outside, disposed in an intermediate position between said retaining member and said second end, a suction source being in fluid connection with said second end.

The intermediate suction opening allows a secondary suction air flow to be created, which generates a flapping or shaking movement of the sock or other article, suitably held at one end or in proximity of one end, with consequent spreading and elimination of wrinkles, folds, creases, twists or the like.

According to an advantageous embodiment of the invention, the suction

opening is provided with an opening and closing valve, so that said opening is intercepted when suitable, for example during the step to insert the article into the suction compartment by suction. The opening can then be opened to start suction therethrough when the article has been fully or partly drawn by suction into the compartment of the device.

In a possible embodiment of the invention, the suction duct can comprise two portions inclined with respect to each other, although it would also be possible to provide the suction duct rectilinear or substantially rectilinear in shape. When the suction duct is provided with two portions inclined with respect to each other, between said two inclined portions there can be disposed a connecting section, and the suction opening can be provided in a first one of said two portions, with which said retaining member is associated; said second end with which the suction source is connected can be positioned in the second of said portions. In a possible embodiment of the device according to the invention, with the first end of the suction duct an element is associated, which modifies the cross section of the suction duct, to facilitate flattening of the article, when it is gradually extracted, i.e. removed from the suction duct. Said element can, e.g. include a block with a shape corresponding to the inner wall of the suction duct, and which can be inserted transversely in said suction duct to reduce the cross section of said duct, forming a transverse passage with a narrow and elongated section. The retaining member can advantageously be controlled and disposed to gradually extract the article from the suction duct, making it pass through said narrow and elongated section and extracting it with a movement in the opposite direction with respect to the suction air flow.

According to a further aspect, the invention relates to a method to spread a flexible and elongated article, wherein said article is inserted at least partly in a suction duct and held in said suction duct in which an air flow is generated, said flow being drawn by suction at least partly through an intermediate suction opening provided in the wall of the suction duct.

According to an advantageous embodiment of the invention, the method comprises the steps of: at least partly introducing said article in said suction duct, in which a suction air flow is generated, said article being held so that it is not drawn

by the air flow; opening said intermediate opening generating an air flow from the outside towards the inside of the suction duct, said flow striking a portion of the article that is free inside the duct. According to an embodiment of the method according to the invention, the article is gradually extracted from the suction duct with a movement in a direction opposite to the direction of the suction air flow.

To facilitate flattening of the article and increase its efficacy, according to an improved embodiment of the method of the present invention, the article can be made to pass through a narrow and elongated cross section, to flatten the article transversely with respect to the extraction movement and to the longitudinal extension thereof. Brief description of the drawings

The present invention will be better understood by following the description and accompanying drawing, which shows a non-limiting practical embodiment of the invention. More specifically, in the drawing Figures 1 to 4 show in a longitudinal section a device according to the invention in different operating steps.

Detailed description of an embodiment of the invention In the example shown, reference number 1 indicates as a whole a device that incorporates the present invention, intended to process articles M formed, for example, by socks having an elastic band B and a toe P. The article M can be semi-finished, for example with an open toe P that has to be sewn in a subsequent processing step. The device 1 has a supporting surface 3, which can be formed by the slat of a conveyor movable in a direction orthogonal to the plane of the figures. Above the surface 3 a belt conveyor 5 is arranged, which is used to insert an article M inside a suction compartment forming part of the device 1 , or to extract it gradually therefrom. Insertion and extraction of the article into and from the suction compartment can also take place using different means, for example by means of a gripper. It would also be possible to insert the article from the opposite end of the suction compartment, making it pass through the entire compartment and collecting it with a gripper or other pick-up member, before reversing suction and proceeding with spreading as described below.

Reference number 7 indicates as a whole a suction duct which, in the example illustrated, has an elbow configuration, i.e. with two sections 7A and

7B inclined with respect to each other, in the example by approximately 90°.

The suction duct 7 has an inner compartment indicated with 9. A first end 11 of the duct 7 is associated with a member 13 having the function of narrowing the cross section of the duct 7 for the purposes indicated hereunder. The member 13 has an element 15 movable according to the double arrow f15 to be inserted into and withdrawn from the suction duct 7.

The movement according to the double arrow f15 of the element 15 is controlled by a piston-cylinder actuator or the like, indicated with 17.

The second end 12 of the suction duct 7 is connected to a suction source, not shown, for example through a pipe 19.

In the wall of the suction duct 7, between the elbow or curve joining the portions 7A, 7B of the duct 7 and the end 11 thereof, a suction port or opening 21 is provided, which can be closed and opened alternately using a valve 23 with an opening and closing actuator.

The device described above operates in the manner illustrated below with reference to the operating sequence in Figures 1 to 4.

In an initial step the element 15 is taken to an upper position leaving a passage with a wide free cross section at the first end 11 of the suction duct 7, so that an article M can easily be gradually inserted inside the suction duct 7. Insertion, according to the arrow F (Figures 1 and 2) takes place through a combination of the movement of the conveyor belt 5 and of suction (arrow A) through the suction pipe 19. The air flow that is generated from the inlet at the end 11 towards the end 12 of the suction duct 7 and the movement of the conveyor 5 allows gradual insertion of the article M.

When a sufficient portion of the article M has entered the inside of the duct 7, with the edge B thereof at the level of the opening 21 or beyond, the valve 23 opens, so that suction through the pipe 19 generates an air flow A1

(Figure 3) mainly drawn through the opening 21 again as a result of the suction source (not shown) connected to the device 1 through the suction pipe 19.

In this step the article M is held, preventing complete insertion thereof inside the suction duct 7, by the conveyor 5 which is stopped. The current of air

drawn through the opening 21 generates a vortical flow inside which the edge B of the article M is positioned, which consequently undergoes to a vigorous shaking and widening action so that it is spread in longitudinal and transverse direction, eliminating any wrinkling, helical twisting, folds or the like. Subsequently, advantageously still continuing the suction through the pipe 19 with air drawn through the opening 21 in communication with outside, the conveyor belt 5 reverses the movement thereof, while the element 15 has been lowered to the position of minimum cross section of the suction duct 7, taking the position in Figures 3 and 4. With reversal of the movement of the conveyor 5, the article M is gradually drawn from the inside of the suction duct 7 towards the outside to be positioned fully on the supporting surface 3 passing under the element 15 and consequently undergoing flattening in a transverse direction by means of the element 15, which has decreased the cross section inside the suction duct 7, through which the article passes. The combination of narrowing the cross section of the passage through the element 15, and of the vortical air flow drawn from the outside environment through the opening 21 due to suction through the pipe 19 and consequent shaking of the article M results in transverse and longitudinal spreading of the article. It is understood that the drawing only shows an example provided by way of a practical embodiment of the invention, which can vary in forms and arrangement without however departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided purely to facilitate reading thereof in the light of the description and accompanying drawing, and do not in any way limit the scope of protection of the claims.