GRASSI, Nerino (Via Solferino 55, Castiglione Stiviere, I-46043, IT)
MAGNI, Antonio (Viale Gagny 58, Tavarnelle Val di Pesa, I-50028, IT)
GRASSI, Nerino (Via Solferino 55, Castiglione Stiviere, I-46043, IT)
Claims
1. A device for handling elongated foldable articles, such as tubular knitted articles, comprising: an elongated hollow member with a first end and a second end, said first end being connectable to a pneumatic feed duct of said articles and said second end being connectable to a suction duct; at said second end, a retention member of said articles; and a side opening, from which said articles are delivered in the spread position; characterized in that at least one movable element, which modifies the cross section of said hollow member during the various operating steps, is disposed inside said hollow member.
2. Device as claimed in claim 1 , characterized in that it includes a plurality of movable elements aligned according to the longitudinal extension of said hollow member, said movable elements being actuatable separately from one another. 3. Device as claimed in claim 1 or 2, characterized in that said movable element or elements are equipped with actuators which can take said movable elements to at least two positions, respectively at a maximum distance from an inner wall of the hollow member and pressing against said inner wall 4. Device as claimed in claim 2 or 3, characterized in that said movable elements are controlled to take: a first idle position, withdrawn with respect to the inner compartment of said hollow member during a step to insert the article into the hollow member; a second position to reduce said cross section during a step to spread the article; and a third position to hold the article against an inner wall of said hollow member.
5. Device as claimed in one or more of the previous claims, characterized in that said hollow member has a conveyor which removes said articles from inside the hollow member.
6. Device as claimed in claim 5, characterized by a side closing member extending longitudinally along said hollow member above said conveyor.
7. Device as claimed in claim 5 or 6, characterized in that said conveyor defines at least in part the base wall of the hollow member.
8. Device as claimed in one or more of claims 5, 6 or 7, characterized in that said conveyor is a belt conveyor, defining at least in part the base of the hollow member.
9. Device as claimed in one or more of the previous claims, characterized in that said hollow member is axially movable in a direction parallel to its longitudinal extension. |
Device for longitudinally spreading a flexible article, such as a tubular knitted article
Description Technical field The present invention relates to devices for handling soft and flexible articles, such as tubular knitted articles, like socks and stockings. In particular, the present invention relates to a device used to longitudinally spread an article of this type, for example to prepare it for subsequent processes, or to arrange it in a predetermined position or with a predetermined orientation. State of the art
In many industrial applications there is the need to handle flexible products, that is soft and foldable products, with forms that are unstable and non geometrically defined. The automation of handling processes of this type of article is particularly difficult, due to their deformability and to the undetermined nature of their shape.
These problems are particularly relevant in the field of hosiery manufacturing, where textile articles such as socks, stockings and pantyhose must be subjected to various types of handling operations. Typically, tubular knitted articles of this type must be unloaded from the production machine (normally a circular knitting machine), the toe sewn, optionally cut and sewn in pairs to form the pantyhose, pressed and so on.
One of the critical aspects in the machining processes of tubular knitted articles is represented by the need to spread the articles according to their longitudinal extension. An example of a device to perform this operation is described in the patent USA n. 5,769,286. Objects and summary of the invention
The object of the present invention is to produce a particularly efficient and reliable device for handling tubular knitted articles or other foldable articles which can have similar handling problems. More specifically, the object of the present invention is to produce a device which allows foldable articles of this type to be extended and spread efficiently. Hereunder the term spreading device is intended as a device which performs the operation to spread the articles, i.e. which spreads them in the direction of their
longitudinal extension, in order, for example, to lay them spread out and, if possible, flat on a supporting surface to facilitate the subsequent handling operations.
In substance, the invention relates to a device for handling elongated foldable articles, such as tubular knitted articles, comprising: an elongated hollow member with a first end and a second end, said first end being connectable to a pneumatic feed duct of said articles and said second end being connectable to a suction duct; at said second end, a retention member of said articles; and a side opening, from which said articles are delivered in the spread position; characterized in that at least one movable element, which modifies the cross section of said hollow member during the various operating steps, is disposed inside said hollow member.
Preferably, the device has a plurality of movable elements aligned according to the longitudinal extension of said hollow member, said movable elements being actuatable separately from one another.
The movable elements, produced for example as pressers actuated by respective actuators of pneumatic, hydraulic or other type, can take at least two positions, respectively at a maximum distance from an inner wall of the hollow member and pressing against said inner wall. According to a preferred embodiment of the invention, the movable elements are controlled to take: a first idle position, withdrawn with respect to the inner compartment of said hollow member during a step to insert the article into the hollow member; a second position to reduce said cross section during a step to spread the article; and a third position to hold the article against an inner wall of said hollow member.
To allow the foldable article to be removed from inside the hollow member remaining correctly in a spread and possibly flat position, according to a particularly advantageous embodiment of the invention, the hollow member has a conveyor which removes said articles from inside the hollow member. This conveyor forms, preferably at least in part, the base wall of the hollow member. A side opening, extending according to the longitudinal direction of the hollow member, can be positioned above it for delivery of the articles. This opening can be closed by a sliding or oscillating door, or by other suitable means, controlled according to the operating sequence of the
device.
According to a possible and preferred embodiment, the conveyor is a conveyor belt, defining at least in part the base of the hollow member.
Further advantageous embodiments of the method and of the device according to the invention are indicated in the appended dependent claims and will be described in greater detail with reference to an example of embodiment. Brief description of the drawings
The invention will now be better understood following the description and accompanying drawing, which shows a non-limiting practical embodiment of the invention. More specifically, in the drawing:
Figure 1 shows a perspective view of the spreading device of the tubular articles;
Figure 2 shows a longitudinal section of the spreading member; Figure 3 shows an enlargement of a detail in Figure 2;
Figures 4 to 7 show an operating sequence of the spreading device. Detailed description of the preferred embodiment of the invention
Figures 1 to 3 show in greater detail the configuration of a spreading device according to the invention, while Figures 4 to 7 show an operating sequence of said device.
The spreading device is indicated as a whole with 27. It includes an elongated hollow member composed of a box structure 150 with a rectangular section (in the example), connected to which are the end of a pneumatic transport duct 7 and a suction mouth 151. The box structure 150 has a side panel 153 attached to a piston-cylinder actuator 155 supported by the upper horizontal wall of the box structure 150. The actuator 155 can control a lifting and lowering movement of the side panel 153 to open and close the box structure 150. In the example shown a conveyor belt 29 runs along the bottom of the box structure 150, in substance defining the lower surface of the compartment or inner volume with rectangular section of the spreading device 27. The lifting movement of the side panel 153 allows a tubular article inside the spreading device 27 to be delivered from the side and transferred out of the spreading device by the conveyor belt 29. Alternatively, the base of the inner compartment of the spreading device can
also be formed of a rigid wall, optionally movable.
In the central zone of the box structure 150 the spreading device has movable elements comprising movable pressers 161 actuated by actuators 163 (five in number in the example shown) which have the dual function, described in greater detail below with reference to an operating sequence, of reducing the cross section of the compartment or inner volume of the spreading device 27, reducing the vertical dimension, during the spreading step of the tubular article, and of allowing complete and correct spreading of said article also at its end which is inserted into the spreading device 27 first. As can be seen in particular in Figures 2 and 3, a screen 165 is arranged between the inside of the spreading device 27 and the suction mouth 151 to prevent the tubular articles penetrating the spreading device 27 from being sucked inside the suction mouth 151. In the example shown the screen 165 is arranged inclined to define a substantially cuneiform volume, arranged at the narrow end of which is a retention member 167, controlled by a piston-cylinder actuator 169 (Figure 3), provided to retain the end of the tubular article orientated forward with respect to the direction of insertion of the tubular article in the spreading device 27. Due to the configuration of the device, the retention member 167 engages one article at a time. If two tubular articles are accidentally fed into the box structure 150 one of them is engaged by the retention member and the other is carried back by suction and returned to the duct 7, thanks to the operating sequence performed by the device, as described below. Consequently, the device 27 also functions as a separator and not just as a spreading device. Alternatively, the screen 165 can be arranged on a surface approximately orthogonal to the direction from which the tubular articles are fed and the retention member can, for example, be composed of a gripper.
The box structure 150 is supported slidingly in the direction of the double arrow f150 to perform a transverse movement with respect to the direction of movement f29 of the conveyor belt 29. This transverse movement according to f150 of the box structure 150 of the spreading device 27 is imparted by a piston-cylinder actuator 171 and its purpose will be described with reference to an operating sequence of the machine.
Operation of the device 27 described above is illustrated with specific
reference to Figures 4 to 7. The various actuators of the device are controlled, to perform the operations described below, by a microprocessor or by a programmable unit, not shown.
An individual tubular article M is sucked inside the pneumatic transport tube 7, which leads to in the inner compartment of the spreading device 27.
The suction that transports the tubular article from the inlet of the pneumatic duct 7 inside the spreading device 27 is applied through the suction mouth
151.
In Figure 4 the tubular article M is entering, sucked through the mouth 151 , the compartment of the spreading device 27 and reaching with one of its ends (which can either be the elastic band or the toe without distinction and randomly) the inclined end screen 165. Travel of the tubular article M terminates according to the arrow F against said screen and is clamped (Figure 5) by the retention member 167 actuated by the actuator 169. At this point the individual pressers 161 associated with the spreading device 27 can be lowered to halfway through their travel by the actuators 163 to take the position shown in Figure 5. In substance, this reduces, at least in the central zone, the cross section (more specifically the height) of the inner compartment of the spreading device 27. By inverting suction inside the duct 7, the tubular article M is pulled and spread with a force applied by the current of air in the direction of the arrow F1 in Figure 5, while the end of the tubular article M engaged against the screen 165 remains fastened there.
At this point, the tubular article M is in the spread position inside the volume of the spreading device 27. If two tubular articles are fed inside the spreading device 27 by error, the second tubular article will not be engaged by the retention member 167, thanks to the particularly narrow configuration of the end zone of the cuneiform volume defined by the screen 165 and will therefore be returned to the duct 7 through inversion of suction and from said duct unloaded, for example, into a container from which the articles M are picked up and inserted in said duct 7.
After the tubular article M has reached the spread position inside the volume 150 of the spreading device 27, the box structure of the spreading device is translated to the left (in the figure) by means of the piston-cylinder
actuator 171 to take the position in Figure 6. In this way the tubular article M is practically positioned entirely over the conveyor belt 29 which defines the base of the inner compartment of the spreading device 27. In the subsequent operating step (Figure 7) the presser 161 which is closest to the end of the article M that entered the inner compartment of the spreading device 27 last is lowered to press the article M against the conveyor belt 29 below. As the tubular articles M which are fed in sequence into the spreading device 27 are all substantially of the same dimension, i.e. of the same size, it is known a priori which of the five pressers 161 is positioned closest to this end of the tubular article M. This allows the correct presser to be actuated by the control unit. Alternatively, optical sensors could be provided inside the spreading device 27 to identify the position of the end of the tubular article M that entered the inner compartment of the spreading device 27 last. The other pressers 161 , positioned to the left of the lowered presser 161 (i.e. on the opposite side with respect to the end in which the screen 165 is positioned), can also be moved downwards, to prevent any portion of the article M projecting slightly from the presser in question from being folded over itself when suction through the screen 151 is actuated again.
With the tubular article M engaged in this way against the upper surface of the conveyor belt 29, the box structure 150 of the spreading device 27 can be translated again from left to right (in the figure) by the actuator 171 to be returned to the position in Figure 7. In this step suction can also be actuated again through the suction mouth 151 to correctly spread the end of the tubular article M which was previously engaged by the retention member 167 and which may not be perfectly aligned with respect to the longitudinal extension of the article M.
At the end of these operations the side panel 153 of the box structure 150 of the spreading device 27 is lifted by the actuator 155 and the conveyor belt 29 is actuated to transfer the spread tubular article out of the inner compartment of the spreading device 27.
It is understood that the drawing only shows an example provided as a practical embodiment of the invention, which may vary in forms and arrangements without however departing from the scope of the concept on which the invention is based. Any reference numbers in the appended
claimed 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.
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